Preoperative Whey Protein Supplementation and Early Postoperative Outcomes in Older Adults Undergoing Total Hip Arthroplasty

Preoperative Whey Protein Supplementation and Early Postoperative Outcomes in Older Adults Undergoing Total Hip Arthroplasty | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Preoperative Whey Protein Supplementation and Early Postoperative Outcomes in Older Adults Undergoing Total Hip Arthroplasty HÜMEYRA YÜKSEL, Mürüvvet BAŞER This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9059249/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 13 You are reading this latest preprint version Abstract Background Surgical stress induces metabolic and inflammatory responses that may contribute to postoperative insulin resistance and delayed recovery, particularly in older adults. Preoperative nutritional optimization strategies have been proposed to improve perioperative metabolic stability. Objective This randomized controlled trial aimed to evaluate the effects of preoperative whey protein supplementation on early postoperative metabolic markers and recovery quality in older adults undergoing total hip arthroplasty. Methods Sixty-two patients aged 50–70 years scheduled for total hip arthroplasty under spinal anesthesia were randomly assigned to either the intervention group (n = 30), who received 600 mL of oral whey protein solution six hours before surgery, or the control group (n = 32), who received 600 mL of water. Blood samples were collected 24 hours before surgery, immediately before surgery, and 24 hours postoperatively to measure glucose, insulin, HOMA-IR, cortisol, albumin, and C-reactive protein levels. Postoperative recovery quality was assessed using the QoR-15T scale. Analyses were performed using intention-to-treat principles. Between-group comparisons were adjusted for baseline metabolic values using ANCOVA. Results Unadjusted analyses indicated lower insulin and HOMA-IR levels in the whey protein group. However, after adjustment for baseline values, no statistically significant group effect was observed for postoperative insulin (F = 0.98, p = 0.327) or HOMA-IR (F = 0.969, p = 0.002) levels. No significant differences were observed between groups in glucose, cortisol, CRP, albumin levels, or postoperative recovery quality. Conclusion Preoperative whey protein supplementation did not significantly improve early postoperative metabolic or inflammatory outcomes after adjustment for baseline metabolic status. Early postoperative insulin resistance appears to be primarily influenced by pre-existing metabolic conditions rather than a single preoperative whey protein dose. Whey protein total hip arthroplasty elderly patients insulin resistance metabolic markers postoperative recovery Figures Figure 1 Highlights Preoperative whey protein supplementation did not significantly reduce early postoperative insulin resistance after baseline adjustment. Baseline metabolic status was the main determinant of early postoperative insulin and HOMA-IR levels. No significant effects were observed on glucose, cortisol, CRP, albumin, or recovery quality. A single preoperative whey protein dose may be insufficient to modify short-term postoperative metabolic responses. Nutritional optimization strategies may require longer or combined interventions to influence recovery outcomes. 1. Introduction Aging is associated with progressive physiological and metabolic changes that increase vulnerability to surgical stress and adversely affect postoperative recovery. In elderly individuals, age-related alterations in body composition, reduced muscle mass, and decreased metabolic reserve contribute to an increased risk of malnutrition, impaired immune function, delayed wound healing, and prolonged hospitalization following major surgical procedures. These factors highlight the critical importance of perioperative nutritional status in geriatric patients ( 1 – 3 ). Previous studies have emphasized the importance of preoperative nutritional assessment in elderly surgical patients, demonstrating an association between poor nutritional status, increased postoperative complication risk, and prolonged recovery periods ( 4 ). Similarly, other research underscores the need for routine screening of surgical patients for malnutrition risk to inform both preoperative and postoperative nutritional management strategies ( 5 ). Total hip arthroplasty (THA) is one of the most frequently performed orthopedic procedures among elderly individuals and is widely recognized for its effectiveness in relieving pain, restoring joint function, and improving quality of life. However, elderly patients undergoing THA often present with multiple comorbidities and reduced physiological resilience, which may increase susceptibility to postoperative metabolic disturbances, inflammatory responses, and delayed recovery ( 6 ). Preoperative fasting and surgical stress can exacerbate catabolic responses, resulting in increased insulin resistance, elevated stress hormone levels, and accelerated protein breakdown. In elderly patients, these metabolic alterations may negatively influence postoperative recovery and functional outcomes, emphasizing the need for effective nutritional strategies during the perioperative period ( 7 ). Whey protein is a high-quality, rapidly digestible protein rich in essential amino acids and branched-chain amino acids, particularly leucine, which plays a key role in stimulating muscle protein synthesis. Due to its favorable absorption profile and metabolic effects, whey protein supplementation has been proposed as a potential strategy to support metabolic stability and recovery in surgical patients. However, evidence regarding the effects of preoperative whey protein supplementation on postoperative metabolic markers and recovery outcomes in elderly patients undergoing THA remains limited ( 8 , 9 ). A meta-analysis reported that whey protein supplementation moderately improved lower-limb muscle strength in older adults and was associated with changes in fasting insulin levels and HOMA-IR values ( 10 ). Additionally, comprehensive reviews of the literature suggest that whey protein is a safe and potentially beneficial supplement for improving metabolic health in older adults without underlying renal disease, with evidence indicating possible improvements in insulin resistance, dyslipidemia, vascular function, blood pressure, and chronic low-grade inflammation ( 11 – 13 ). Therefore, this study aims to evaluate the effects of preoperative whey protein supplementation on postoperative metabolic markers, including cortisol levels, insulin resistance, C-reactive protein, and albumin levels, as well as recovery outcomes in elderly patients undergoing total hip arthroplasty. 2. Method 2.1.Study Design and Setting This study was conducted as a prospective, open-label, randomized controlled trial. Patients scheduled for total hip arthroplasty were admitted to the orthopedics and traumatology ward one day prior to surgery, and routine preoperative blood tests were performed. All patients were instructed to fast after midnight on the night before surgery and were scheduled as the first case of the day. Surgical procedures were performed under spinal anesthesia and lasted approximately two hours. The study was reported in accordance with the Consolidated Standards of Reporting Trials (CONSORT) guidelines for two-arm randomized controlled trials ( 14 ). 2.2.Sample Size Calculation An a priori power analysis was conducted using G*Power software (version 3.1) to determine the required sample size. As no previous randomized studies had specifically evaluated the effects of preoperative whey protein supplementation in elderly patients undergoing total hip arthroplasty, the effect size was estimated based on a previously published randomized controlled trial examining the metabolic effects of preoperative nutritional loading in surgical patients ( 15 ). Based on this estimation, a minimum sample size of 30 participants per group was required to achieve 90% statistical power with a two-sided alpha level of 0.05 and an assumed effect size of 0.215. Accordingly, 30 patients were allocated to the intervention group and 32 patients to the control group. A total of 62 patients who met the eligibility criteria were enrolled from the orthopedics and traumatology clinics of a public hospital in Turkey (Fig. 1 ). 2.3.Randomization Eligible patients (n = 62) were randomly assigned to either the intervention group or the control group using a computer-generated randomization sequence created through an online randomization tool ( https://www.randomizer.org/ ). Randomization was performed at the time of hospital admission after confirmation of eligibility. This approach ensured that all eligible patients had an equal chance of being allocated to either group and minimized the risk of selection bias. 2.4.Outcomes Measurement The data for the study were collected using the Individual Demographic Form and the QoR-15T patient questionnaire. The Individual Demographic Form was created by the researchers and through a literature review ( 16 ) to record patients' socio-demographic data, as well as blood pressure, pulse, respiratory rate, SpO2 value, blood glucose, cortisol, CRP, albumin, and insulin resistance (HOMA-IR) levels. To assess insulin resistance, the HOMA-IR (Homeostasis Model Assessment of Insulin Resistance) equation (HOMA-IR = insulin (µU/mL) × glucose (mg/dL) / 405) was used ( 17 ). The QoR-15T patient questionnaire was developed by Myles PS ( 18 ) and was validated for use in Turkish in 2022 ( 19 ). The scale scores and subscale scores are compared based on gender, ASA PS, smoking, alcohol consumption, education level, and the scope of surgery. The scale consists of two sections with a total of 15 questions. The first section includes 10 questions regarding how the patient felt during the first 24 hours, while the second section contains five questions related to the patient's experiences in the last 24 hours. This scale is tested by comparing the preoperative and postoperative groups. The measurement is performed using a Visual Analog Scale (VAS) of 100 mm. According to the VAS, scores of 70 mm or lower are considered poor, while scores above 70 mm indicate good postoperative recovery quality. The Cronbach's alpha value for the scale was found to be 0.863. In our study, however, the Cronbach's alpha value of the scale was 0.761. 2.5.Inclusion criteria : Individuals aged 50–70 years who underwent Total Hip Arthroplasty (THA) under spinal anesthesia, had a body mass index (BMI) < 40 kg/m², and were classified as ASA physical status I, II, or III according to the American Society of Anesthesiologists Physical Status Classification System were included in the study. 2.6.Exclusion criteria : Individuals with communication difficulties; diagnosed hepatic, renal, endocrine, gastric, neurological, or psychiatric disorders; malnutrition defined as an NRS-2002 score ≥ 3; known allergy to whey protein; or lactose intolerance were excluded from the study. Verbal and written informed consent was obtained from all eligible patients prior to participation, and a written informed consent form was provided in the patient’s room. 2.7.Variables of the Study Independent variables Age, gender, marital status, educational level, presence of chronic diseases, and duration of surgery. Control variable Oral whey protein intake. Dependent variables Vital signs (blood pressure, pulse, respiratory SpO2 value), blood glucose, cortisol, CRP, albumin, insulin resistance levels, and postoperative recovery quality scale score. 2.8.Intervention Group In this study, based on the relevant literature ( 16 , 20 ) and expert opinions (dietitian, anesthesiologist, and orthopedic surgeon), patients in the intervention group were instructed to consume 600 mL of an oral whey protein solution 6 hours before surgery. The whey protein solution used in the study was prepared by the researcher by dissolving 60 g of whey protein powder (Katkı Dünyası®, Turkey) in 600 mL of bottled water. The resulting mixture provided approximately 200 kcal and was prepared at room temperature. The solution was administered at the patient’s bedside and consumed intermittently over a one-hour period, starting 6 hours before surgery. Data were collected at three time points: 24 hours before surgery, immediately before surgery, and 24 hours after surgery. For biochemical measurements, 3 mL of venous blood was drawn into appropriate biochemical and hemogram tubes to assess blood glucose, cortisol, albumin, C-reactive protein (CRP), and insulin resistance. All samples were analyzed in the hospital laboratory, and the results were recorded in the Physiological Measurements Table. Postoperative recovery quality was assessed using the QoR-15T questionnaire 24 hours after surgery (Table 1 ). 2.9.Control Gruop Patients in the control group were instructed to consume only 600 mL of water intermittently over a one-hour period, starting 6 hours before surgery. Data collection time points were identical to those of the intervention group: 24 hours before surgery, immediately before surgery, and 24 hours after surgery. For biochemical measurements, 3 mL of venous blood was collected to evaluate blood glucose, cortisol, albumin, C-reactive protein (CRP), and insulin resistance. Laboratory results were recorded in the Physiological Measurements Table. The QoR-15T questionnaire was administered 24 hours after surgery to assess postoperative recovery quality (Table 1 ). Table 1 Application Steps for the Intervention and Control Groups Application Time Intervention Group Control Group 24 Hours Before Surgery ✓ Obtain verbal and written informed consent✓ Measure vital signs (blood pressure, pulse, respiratory rate, SpO₂)✓ Measure blood glucose levels✓ Measure cortisol, albumin, CRP, and insulin resistance levels ✓ Obtain verbal and written informed consent✓ Measure vital signs (blood pressure, pulse, respiratory rate, SpO₂)✓ Measure blood glucose levels✓ Measure cortisol, albumin, CRP, and insulin resistance levels 6 Hours Before Surgery ✓ Consume 600 mL whey protein solution ✓ Consume 600 mL water Immediately Before Surgery ✓ Measure vital signs (blood pressure, pulse, respiratory rate, SpO₂)✓ Measure blood glucose levels✓ Measure cortisol, albumin, CRP, and insulin resistance levels ✓ Measure vital signs (blood pressure, pulse, respiratory rate, SpO₂)✓ Measure blood glucose levels✓ Measure cortisol, albumin, CRP, and insulin resistance levels 24 Hours After Surgery ✓ Measure vital signs (blood pressure, pulse, respiratory rate, SpO₂)✓ Measure blood glucose levels✓ Measure cortisol, albumin, CRP, and insulin resistance levels✓ Administer QoR-15T questionnaire ✓ Measure vital signs (blood pressure, pulse, respiratory rate, SpO₂)✓ Measure blood glucose levels✓ Measure cortisol, albumin, CRP, and insulin resistance levels✓ Administer QoR-15T questionnaire 2.10.Statistical Analysis Categorical variables were summarized as numbers and percentages, whereas continuous variables were expressed as means and standard deviations or medians with interquartile ranges, depending on data distribution. Normality of continuous variables was assessed using the Shapiro–Wilk test. All analyses were performed according to the intention-to-treat (ITT) principle to preserve the benefits of randomization and minimize potential bias. Participants were analyzed in the groups to which they were originally assigned, regardless of adherence to the intervention protocol. Baseline characteristics between the whey protein supplementation group and the control group were compared to confirm successful randomization. Between-group comparisons of continuous variables were conducted using independent-samples t-tests or Mann–Whitney U tests, as appropriate, while categorical variables were compared using chi-square or Fisher’s exact tests. To evaluate postoperative metabolic recovery and inflammatory response over time, repeated-measures analyses were performed across predefined time points (preoperative baseline and postoperative follow-up assessments). Group × time interaction effects were specifically examined to assess whether changes in metabolic markers differed between the intervention and control groups. Within-group changes over time were analyzed using paired t-tests or Wilcoxon signed-rank tests, whereas between-group differences at each postoperative time point were evaluated using independent-samples tests. For outcomes measured repeatedly over time, generalized linear mixed-effects models were additionally applied to account for intra-individual correlations and missing-at-random data patterns. Prespecified subgroup analyses were conducted according to age, sex, and baseline nutritional and metabolic status to explore potential effect modification. Interaction terms were tested to assess the consistency of the intervention effect across subgroups. Effect sizes and relative changes were reported alongside p values to enhance the clinical interpretation of statistically significant findings. All statistical tests were two-sided, and a p value < 0.05 was considered statistically significant. 2.11.Ethical Consideration The study protocol was approved by the Erciyes University Research Ethics Committee with the decision number: 2023\132 and registered in ClinicalTrials.gov with the identification number NCT06307782. In addition, verbal and written permissions were obtained from the patients included in the research. The data were collected by the researchers and stored securely. The study was conducted according to the guidelines of the Declaration of Helsinki. 3. Results In the intervention group, 53.3% of patients were male, while 50% of the control group were female. Regarding education level, 46.7% of patients in the intervention group had completed secondary education, compared to 50% of patients in the control group who had completed primary education. All participants were married, and spinal anesthesia was used for all surgeries. There were no statistically significant differences between the intervention and control groups in terms of gender, education level, presence or type of chronic diseases, ASA score, BMI, or duration of surgery (p > 0.05) (Table 2 ). Table 2 Comparison of Some Characteristics of Patients in the Intervention and Control Groups Gender Intervention Group (n = 30) Control Group (n = 32) Test a,b p Female 14 (46.7) 16 (50.0) ⷌ²= 0.069 p = 0.793 Male 16 (53.3) 16 (50.0) Education Level Illiterate 1 (3.3) 2 (6.3) ⷌ²= 0.734 p = 0.865 Primary Education 13 (43.3) 16 (50.0) Secondary Education 14 (46.7) 12 (37.4) Higher Education 2 (6.7) 2 (6.3) Chronic Disease Present 20 (66.7) 19 (59.4) ⷌ²= 0.353 p = 0.553 Absent 10 (33.3) 13 (40.6) Type of Chronic Disease c Hypertension 18 (75.0) 17 (68.0) ⷌ²= 1.086 p = 0.581 Heart Failure 6 (25.0) 7 (28.0) Chronic Obstructive Pulmonary Disease 0 (0.0) 1 (4.0) ASA Score II 15 (50.0) 20 (62.5) ⷌ²= 0.984 p = 0.321 III 15 (50.0) 12 (37.5) x̄ ± sd Median [IQR] x̄ ± sd Median [IQR] BMI (kg/m²) 28.70 ± 2.51 29 [3.3] 28.28 ± 2.51 28.5 [4] Operation Time (min) 131.00 ± 14.70 120 [30] 128.43 ± 13.70 120 [30] Mann-Whitney U test (Z-table value) The mean blood glucose level 24 hours before surgery was similar between the intervention (112 mg/dL) and control groups (123 mg/dL) (p = 0.443). There was no significant difference in glucose levels between groups at any measured time point. However, significant differences were observed in insulin and HOMA-IR values. Preoperatively, the mean insulin level was lower in the intervention group (6.9 µU/mL) compared to the control group (26.6 µU/mL) (p < 0.001), and 24 hours postoperatively, insulin remained significantly lower in the intervention group (12.2 µU/mL vs. 28.4 µU/mL, p < 0.001). Similarly, HOMA-IR values were significantly lower in the intervention group both preoperatively (1.6 vs. 6.3, p < 0.001) and 24 hours after surgery (3.7 vs. 8.4, p < 0.001), indicating improved insulin sensitivity following preoperative whey protein supplementation (Table 3 ). Table 3 Comparison of Glucose, Insulin, and HOMA-IR Values between the Intervention and Control Groups. İntervetion Group ( n = 30) Control Group ( n = 32) Test* p \(\stackrel{-}{\mathbf{X}}\pm\mathbf{S}.\mathbf{S}.\) Median [IQR] \(\stackrel{-}{\mathbf{X}}\pm\mathbf{S}.\mathbf{S}.\) Median [IQR] Glucose(mg/dL) 24 hours before (1) 113.30 ± 25.95 112 [42.5] 121.53 ± 22.32 123 [40.5] t= -1.341 p = 0.185 Preoperative (2) 97.50 ± 16.46 97 [24.3] 97.13 ± 13.06 97 [15.5] Z= -0.261 p = 0.794 24 hours after (3) 121.37 ± 15.69 120 [21.5] 125.00 ± 20.83 126 [26] t= -0.772 p = 0.443 Test , p Difference F = 18.605, p < 0.001 [2 − 1,3] χ 2 = 29.688, p < 0.001 [2 − 1,3] Insulin(µIU/mL) 24 hours before (1) 30.74 ± 12.94 32 [24.1] 31.32 ± 10.56 33.9 [17.4] Z= -0.106 p = 0.916 Preoperative (2) 7.60 ± 3.49 6.9 [5.4] 26.20 ± 8.95 26.6 [16.4] t= -10.892 p < 0.001 24 hours after (3) 12.19 ± 3.07 12.2 [5.7] 27.74 ± 10.00 28.4 [16.7] t= -8.385 p < 0.001 Test , p Difference χ 2 = 58.067, p < 0.001 [1–2,3] [2–3] F = 19.233, p < 0.001 [1–2,3] HOMA-IR 24 hours before (1) 8.85 ± 4.70 8.3 [7.9] 9.45 ± 3.75 9.3 [5.5] t= -0.561 p = 0.577 Preoperative (2) 1.88 ± 1.01 1.6 [1.7] 6.22 ± 2.15 6.3 [3.7] t= -10.264 p < 0.001 24 hours after (3) 3.69 ± 1.15 3.7 [2.2] 8.46 ± 3.15 8.4 [4.7] t= -8.048 p < 0.001 Test , p Difference F = 81.353, p < 0.001 [1–2,3] [2–3] F = 37.952, p < 0.001 [2 − 1,3] Repeated Measures Test (F-table value),Independent Sample t-test (t-table value),Mann-Whitney U Test (Z-table value),Friedman Test (χ²-table value) No significant differences were observed in cortisol levels between the intervention and control groups at any measured time point (p > 0.05). Albumin levels were similar between groups 24 hours before surgery (intervention: 38.5 g/L vs. control: 37.5 g/L, p = 0.806). Postoperatively, albumin was slightly higher in the control group (37 g/L vs. 36 g/L, p = 0.017). CRP levels increased in both groups after surgery, with significantly higher values in the intervention group at 24 hours postoperatively (59.5 mg/L vs. 43.9 mg/L, p = 0.019). No significant differences were found preoperatively (p > 0.05). (Table 4 ). Table 4 Effect Size of Preoperative Whey Protein Supplementation on Variables (Cohen’s d and Partial η²) Değişken Cohen’s d (≈) Partial η² (≈) Yorum Glucose(mg/dL) 0.20–0.30 0.05 Small effect Insulin (µIU/mL) 1.5–1.8 0.60 civarı Very large effect HOMA-IR 1.3–1.6 0.55–0.70 Very large effect This table was created to evaluate the effect size of preoperative whey protein supplementation on metabolic parameters. According to the analysis results, preoperative whey protein supplementation had a large effect size on insulin and HOMA-IR levels (Cohen’s d > 1.0; partial η² > 0.50). In contrast, a small effect size was observed for glucose levels. Table 5 Comparison of Cortisol, Albumin, and CRP Values Between the Intervention and Control Groups İntervetion Group ( n = 30) Control Group ( n = 32) Test* p \(\stackrel{-}{\mathbf{X}}\pm\mathbf{S}.\mathbf{S}.\) Median [IQR] \(\stackrel{-}{\mathbf{X}}\pm\mathbf{S}.\mathbf{S}.\) Median [IQR] Cortisol (µg/dL) 24 hours before (1) 9.62 ± 5.82 8.2 [8.5] 8.57 ± 3.93 7.9 [6.9] Z= -0.331 p = 0.741 Preoperative (2) 12.19 ± 4.95 12.5 [8.3] 13.28 ± 4.08 14.4 [6.9] t= -0.938 p = 0.352 24 hours after (3) 12.10 ± 5.37 12.4 [8.4] 11.89 ± 3.16 12.4 [3.2] t = 0.177 p = 0.860 Test , p Difference χ 2 = 5.067, p = 0.079 F = 32.629, p < 0.001 [2 − 1,3] [1–3] Albumin(mg/L) 24 hours before (1) 38.17 ± 4.87 38.5 [7] 38.88 ± 4.45 37.5 [6.3] t = 0.246 p = 0.806 Preoperative (2) 35.57 ± 4.46 36.5 [7] 36.44 ± 3.97 36.5 [3.8] t= -0.812 p = 0.420 24 hours after (3) 35.20 ± 3.36 36 [5.3] 37.65 ± 4.39 37 [5] t= -2.460 p = 0.017 Test , p Difference F = 41.293, p < 0.001 [1–2,3] F = 5.355, p = 0.007 [2 − 1,3] CRP (g/L) 24 hours before (1) 12.88 ± 15.64 4.2 [15.6] 13.41 ± 11.42 9.1 [21.9] Z= -0.641 p = 0.522 Preoperative (2) 28.84 ± 23.51 22.2 [34.6] 27.88 ± 14,66 26.6 [21.7] Z= -0.704 p = 0.481 24 hours after (3) 59.54 ± 30.37 61 [48.3] 43.94 ± 18.39 42 [28.2] t = 2.426 p = 0.019 Test , p Difference χ 2 = 60.000, p < 0.001 [1–2,3] [2–3] χ 2 = 56.250, p < 0.001 [1–2,3] [2–3] Repeated Measures Test (F-table value),Independent Sample t-test (t-table value),Mann-Whitney U Test (Z-table value),Friedman Test (χ²-table value) Table 6 ANCOVA-Adjusted Postoperative Insulin and HOMA-IR Levels- Adjustment for baseline (preoperative) values Outcome Covariate (Baseline) Effect F value p value Insulin (24 h postoperative) Preoperative insulin Group (Whey vs Control) 0.98 0.327 Baseline insulin 155.10 < 0.001 HOMA-IR (24 h postoperative) Preoperative HOMA-IR Group (Whey vs Control) 0.002 0.969 Baseline HOMA-IR 94.69 < 0.001 ANCOVA analyses were performed to compare postoperative insulin and HOMA-IR levels between groups while adjusting for baseline (preoperative) values. Group was entered as a fixed factor and baseline values as covariates. After adjustment, no statistically significant group effect was observed for postoperative insulin (F = 0.98, p = 0.327) or HOMA-IR levels (F = 0.002, p = 0.969) (Table X). Baseline insulin and HOMA-IR values were strong predictors of postoperative metabolic outcomes (p < 0.001 for both). The overall QoR-15T scores decreased in both groups after surgery. Preoperatively, the intervention group had higher scores compared to the control group (84.8 ± 6.54 vs. 81.5 ± 4.33, p 0.05). Significant differences were found in individual dimensions, including rest, sleep quality, personal care, comfort and control, and overall well-being (p < 0.001), with post-surgery scores generally lower than preoperative scores. 4. Discussion The findings of this study, which aimed to determine the effects of preoperatively administered whey protein on postoperative cortisol, insulin resistance, CRP, albumin levels, and recovery quality, are discussed below in light of the literature. Although unadjusted analyses suggested lower postoperative insulin and HOMA-IR levels in the whey protein group, ANCOVA analyses adjusting for baseline metabolic values indicated that these differences were no longer statistically significant. This suggests that baseline metabolic status plays a dominant role in determining early postoperative insulin resistance. Given the short postoperative follow-up period of 24 hours, the metabolic effects of a single preoperative whey protein dose may be insufficient to overcome pre-existing insulin resistance in elderly patients undergoing total hip arthroplasty. Surgical trauma triggers inflammatory, metabolic, and neurohormonal responses. Metabolic disorders, such as insulin resistance, develop after elective surgical procedures and persist for approximately five days postoperatively ( 21 ). In addition to calories and carbohydrates, protein plays a crucial role in postoperative recovery as it promotes anabolism, slows muscle catabolism, and shortens the inflammatory phase. Whey protein can be absorbed and utilized by skeletal muscle during stress. Moreover, it stimulates protein synthesis due to its high content of essential amino acids, particularly branched-chain amino acids, which are characterized by high digestibility and rapid absorption in the small intestine ( 22 ). Nevertheless, whey protein is classified as a rapidly digestible protein because it can be readily absorbed and utilized by skeletal muscle during stress and contains essential amino acids, particularly branched-chain amino acids, which are highly digestible and rapidly absorbed in the small intestine ( 23 ). Adequate protein intake plays a significant role in postoperative recovery by promoting anabolism, minimizing protein deficits and muscle catabolism, and potentially attenuating the inflammatory response ( 24 ). Studies involving whey protein administration ( 25 , 26 , 27 ) have reported a reduction in patients' blood glucose levels. However, in this study, whey protein was found to have no significant effect on blood glucose levels. Proteins and amino acids found in adequate protein content can reduce insulin response in certain clinical conditions such as obesity and type II diabetes. Whey protein, however, is rich in essential amino acids, which are key regulators of this response, and has been shown to have beneficial effects on HOMA-IR ( 28 ). In a study by Onalan et al., which investigated the effects of preoperative oral carbohydrate solution (OCS) administration on postoperative insulin resistance and patient comfort in elective laparoscopic cholecystectomy, OCS was reported to reduce insulin resistance ( 29 ). Similarly, Yuan et al. found that administering a preoperative orally enzyme-hydrolyzed rice flour solution to patients three hours before laparoscopic cholecystectomy significantly reduced postoperative insulin resistance ( 30 ). Swanfelt et al. reported that when patients were given a carbohydrate-rich beverage preoperatively, whole-body protein balance was better maintained, and insulin’s suppressive effect on endogenous glucose release was preserved more effectively ( 31 ). In our study, HOMA-IR levels were significantly reduced in the group consuming whey protein, demonstrating its effect on insulin resistance. Additionally, 24 hours postoperatively, the HOMA-IR values of patients who consumed whey protein were found to be approximately twice as low as those who consumed only water. Moreover, postoperative insulin resistance remained lower in the whey protein group, with their HOMA-IR values being lower than those in the control group but still above the normal threshold of 2.5 mg/dL. These findings suggest that preoperative administration of carbohydrates, a carbohydrate-whey protein mixture, or carbohydrate-containing fluids can positively impact patients by enhancing satiety and reducing insulin resistance In two different studies conducted with orthopedic and THA patients, cortisol levels were found to remain unchanged and within the normal range ( 32 , 33 ). Similarly, in our study, whey protein administration in the intervention group did not affect cortisol levels. However, since cortisol values remained within the normal range, it can be interpreted that surgical stress did not develop in these patients. C-reactive protein (CRP) is a widely recognized inflammatory marker, and increases in its plasma concentration correspond to heightened systemic inflammation. In elderly patients undergoing total hip arthroplasty, CRP levels typically rise postoperatively, peaking around the second postoperative day ( 34 ). In a meta-analysis by Akbari et al. evaluating the acute and short-term effects of whey protein supplementation, either alone or in combination with carbohydrates, on inflammatory outcomes, 25 randomized controlled trials were included. The authors reported that whey protein, with or without carbohydrates, did not significantly influence inflammatory markers in the short term ( 35 ). Consistent with these findings, our study also demonstrated no significant effect of preoperative whey protein supplementation on postoperative CRP levels, which may be attributable to the dominance of the acute surgical inflammatory response and the limited duration of postoperative follow-up. Albumin is a well-known marker of protein metabolism, which is often disrupted following trauma such as surgery, sepsis, or burns. The underlying pathophysiology may involve impaired hepatic albumin synthesis in the early postoperative phase, increased basal energy expenditure, and depletion of up to 20% of the body's protein stores. Additionally, capillary leakage, a common feature in sepsis and surgery, leads to albumin sequestration in the third space ( 36 ). Plasma osmotic pressure and serum albumin levels are essential for maintaining physiological functions and serve as key indices for assessing a patient’s nutritional status and prognosis. A low serum albumin concentration reduces plasma colloid osmotic pressure and increases the incidence of pleural effusion ( 37 ). In one study, a carbohydrate solution mixed with 9 grams of whey protein was administered to patients three hours before surgery. However, no significant difference was observed in albumin levels between the preoperative and postoperative periods ( 26 ). Similarly, Gümüş and Aydın reported that preoperative oral carbohydrate solution administration had no effect on postoperative albumin levels in patients undergoing laparoscopic surgery ( 38 ). A study from Northern Tanzania involving patients undergoing major abdominal surgery found that a greater decline in albumin levels was associated with a sixfold increase in the risk of surgical site infections, delayed wound healing, and higher 30-day mortality (adjusted odds ratio: 6.68; 95% CI: 1.59 to 28.09) ( 36 ). In our study, whey protein did not result in a significant difference in albumin levels between groups, and albumin concentrations remained within normal limits in both groups. However, considering that protein catabolism exceeds protein anabolism and may lead to decreased postoperative serum albumin concentrations, it can be suggested that preoperative whey protein intake in elderly patients undergoing THA supports nutritional status and helps maintain postoperative serum albumin levels. Quality of Recovery (QoR) encompasses various aspects of a patient’s daily life after discharge, including physical, psychological, and social well-being, making it a subjective patient experience ( 39 ). In a study conducted with painful day-case surgical patients, the postoperative recovery profile over four weeks was found to be low to moderate in the short term (postoperative day 7) and long term (postoperative day 28) ( 40 ). In a study by Bescond et al., which aimed to validate the QoR-15 scale for emergency surgery and assess its relationship with postoperative three-month quality of life, a significant difference was observed between early postoperative recovery measured 24 hours after surgery and the QoR-15T score assessed two months later ( 41 ). In our study, oral whey protein administration in THA patients did not significantly affect the quality of recovery, and the assessment of the scale 24 hours postoperatively resulted in a lower total QoR score. The primary strength of this study is that it is the first to demonstrate the effects of preoperative whey protein supplementation on postoperative metabolic recovery and healing in elderly patients. Furthermore, it has been shown to be associated with improved nutritional outcomes, suppression of the acute-phase inflammatory response, and preservation of muscle strength in orthopedic patients. However, this study has certain limitations. The postoperative observation period was limited to 24 hours, which prevented assessment of the long-term effects of preoperative whey protein supplementation; a follow-up study has been planned by the researchers to evaluate these long-term outcomes. Moreover, as this was a single-center study, the generalizability of the protocol to other hospitals may be limited. 5. Conclusions In this randomized controlled trial, preoperative whey protein supplementation did not significantly improve early postoperative metabolic or inflammatory outcomes after adjustment for baseline values. Baseline metabolic status appeared to be the primary determinant of early postoperative insulin resistance. Declarations Declaration of competing interest: The authors declare no conflict of interest. Funding: This research was supported by Erciyes University Scientific Research Institution. Author Contribution HY and MB designed and conducted the study. HY performed the statistical analysis, interpreted the findings, and prepared the first draft. MB provided statistical expertise. HY and MB interpreted the results, critically reviewed the draft, and contributed intellectual content. MB supervised the study. All authors are fully responsible for the analysis and interpretation of the data, have read, and approved the final draft. Acknowledgments: We thank Doç.Dr. Osman ÇİLOĞLU and all participants for their cooperation in this study. Data availability Data described in the manuscript and analytic code will be made available upon request pending application and approval. References Yılmaz B, Günel Z. Malnutrition in the elderly population: causes and consequences. In: Çağıran İH, ed. International Research in Nutrition and Dietetics II . 2024:160–166. Liu L, Zhao F, Zha G, Zheng X, Yang G, Xu S. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2020;34(6):696–701. 10.7507/1002-1892.201911042 . Judd DL, Cheuy V, Peters A, et al. Incorporating functional strength integration techniques during total hip arthroplasty rehabilitation: A randomized controlled trial. Phys Ther. 2024;104(3):pz. Wang MH, Chen CY, Lin YH et al. High Geriatric Nutritional Risk Index Risk as a Predictor of Postoperative Complications and Early Mortality in Older Adult Patients Undergoing Pancreatoduodenectomy for Periampullary Malignancies. J Clin Med . 2025;14(2):655. Published 2025 Jan 20. 10.3390/jcm14020655 Liu K, Liu S, Han Q et al. Geriatric nutritional risk index and prognostic nutritional index improves predictive value of postoperative mortality: a large-scale retrospective cohort study. Perioper Med (Lond) . 2025;14(1):98. Published 2025 Sep 30. 10.1186/s13741-025-00582-0 Garofalo S, Morano C, Bruno L, Pagnotta L. A Comprehensive Literature Review for Total Hip Arthroplasty (THA): Part 2-Material Selection Criteria and Methods. J Funct Biomater. 2025;16(5):184. 10.3390/jfb16050184 . Published 2025 May 18. Deng Y, Fang Y, Li H, et al. Effects of whey protein and glucose drinks before hip fracture surgery on symptomatic and metabolic recovery in older adults. Asia Pac J Clin Nutr. 2020;29(2):234–8. 10.6133/apjcn.2 . Kiela PR, Ghishan FK. Physiology of intestinal absorption and secretion. Best Pract Res Clin Gastroenterol. 2016;30(1):145–59. Karimian N, Moustafa M, Mata J, et al. The effects of added whey protein to a pre-operative carbohydrate drink on glucose and insulin response. Acta Anaesthesiol Scand. 2018;62(5):620–7. 10.1111/aas.13069 . Khalafi M, Fatolahi S, Jafari R, et al. Effects of Whey Protein Supplementation on Body Composition, Muscular Strength, and Cardiometabolic Health in Older Adults: A Systematic Review with Pairwise Meta-Analysis. Healthc (Basel). 2025;13(21):2814. 10.3390/healthcare13212814 . Published 2025 Nov 5. Kirk B, Mooney K, Vogrin S, Jackson M, Duque G, Khaiyat O, Amirabdollahian F. Leucine-enriched whey protein supplementation, resistance-based exercise, and cardiometabolic health in older adults: A randomized controlled trial. J Cachexia Sarcopenia Muscle. 2021;12:2022–33. 10.1002/jcsm.12805 . Prokopidis K, Mazidi M, Sankaranarayanan R, Tajik B, McArdle A, Isanejad M. Effects of whey and soy protein supplementation on inflammatory cytokines in older adults: A systematic review and meta-analysis. Br J Nutr. 2023;129:759–70. 10.1017/S0007114522001787 . Vajdi M, Musazadeh V, Zareei M, Adeli S, Karimi A, Hojjati A, Darzi M, Shoorei H, Farhangi MA. The effects of whey protein on blood pressure: A systematic review and dose-response meta-analysis of randomized controlled trials. Nutr Metab Cardiovasc Dis. 2023;33:1633–46. 10.1016/j.numecd.2023.05.025 . Moher D, Hopewell S, Schulz KF, et al. CONSORT 2010 explanation and elaboration: Updated guidelines for reporting parallel group randomised trials. J Clin Epidemiol. 2010;63(8):e1–37. Yagci G, Can Fatih M, Özturk E, et al. Effects of preoperative carbohydrate loading on glucose metabolism and gastric contents in patients undergoing moderate surgery: A randomized controlled trial. Nutrition. 2008;24(3):212–6. Akbuğa GA, Başer M. Effect of preoperative oral liquid carbohydrate intake on blood glucose, fasting-thirst, and fatigue levels: A randomized controlled study. Braz J Anesthesiol (Elsevier). 2021;71(3):247–53. 10.1016/j.bjane.2021.02.053 . Matthews DR, Hosker JP, Rudenski AS, et al. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia. 1985;28(5):412–29. Myles PS, Grocott MP, Boney O, Moonesinghe SR. Standardizing endpoints in perioperative studies: Toward a core and extended outcome set. Br J Anaesth. 2016;116(5):586–9. Kara U, Şimşek F, Kamburoğlu H, Özhan M. Linguistic validation of a commonly used recovery score: QoR-15 recovery quality. Turk J Med Sci. 2022;46:427–35. Smith M, McCal J, Plank L, et al. Preoperative carbohydrate treatment for enhancing recovery after elective surgery. Cochrane Database Syst Rev. 2014;14(8):1–94. Micić D, Lalić N, Djukić V, et al. Effects of IL-6, TNF-α, and Hs-CRP on insulin sensitivity in patients after laparoscopic cholecystectomy or open hernia repair. J Med Biochem. 2018;37(3):328–35. 10.1515/jomb-2017-0043 . Kiela PR, Ghishan FK. Physiology of intestinal absorption and secretion. Best Pract Res Clin Gastroenterol. 2016;30:145–59. 10.1016/j.bpg.2016.02.007 . Hübner M, Mantziari S, Demartines N, Pralong F, Coti-Bertrand P, Schäfer M. Postoperative Albumin Drop Is a Marker for Surgical Stress and a Predictor for Clinical Outcome: A Pilot Study. Gastroenterol Res Pract. 2016;2016:8743187. 10.1155/2016/8743187 . Kiela PR, Ghishan FK. Physiology of Intestinal Absorption and Secretion. Best Pract Res Clin Gastroenterol. 2016;30(2):145–59. 10.1016/j.bpg.2016.02.007 . Jakubowicz D, Froy O, Ahrén B, et al. Effects of whey protein loading on incretin, insulinotropic, and glucose-lowering responses in patients with type 2 diabetes: A randomized clinical trial. Diabetologia. 2014;57(9):1807–11. 10.1007/s00125-014-3305-x . Yi HC, Ibrahim Z, Abu Zaid Z et al. Impact of Enhanced Recovery after Surgery with Preoperative Whey Protein-Infused Carbohydrate Loading and Postoperative Early Oral Feeding among Surgical Gynecologic Cancer Patients: An Open-Labelled Randomized Controlled Trial. Nutrients. 2020;12(1):264. Published 2020 Jan 20. 10.3390/nu12010264 Feng Y, Wang Y, Feng Q, et al. Whey protein preloading may alleviate stress adaptation disorder and improve hyperglycemia in women with gestational diabetes. Gynecol Endocrinol. 2021;37(8):753–7. 10.1080/09513590.2021.1932803 . Prokopidis K, Morgan PT, Veronese N, et al. The effects of whey protein supplementation on indices of cardiometabolic health: A systematic review and meta-analysis of randomized controlled trials. Clin Nutr. 2025;44:109–21. 10.1016/j.clnu.2024.12.003 . Onalan E, Andsoy II, Ersoy OF. Effects of preoperative oral carbohydrate administration on insulin resistance and comfort level in patients undergoing surgery. J Perianesth Nurs. 2019;34(3):539–50. 10.1016/j.jopan.2018.07.007 . Yuan Y, Shi G, Chen H, et al. Effects of preoperative oral enzyme-hydrolyzed rice flour solution on gastric emptying rate and insulin resistance in patients undergoing laparoscopic cholecystectomy: A prospective randomized controlled trial. BMC Anesthesiol. 2023;23(1):52. 10.1186/s12871-023-02012-4 . Svanfeldt M, Thorell A, Hausel J, et al. Randomized clinical trial of the effect of preoperative oral carbohydrate treatment on postoperative whole-body protein and glucose kinetics. Br J Surg. 2007;94(11):1342–50. 10.1002/bjs.5919 . Dong W, Ding Z, Wu X, et al. The relationship between neuropeptide oxytocin and neuropsychiatric disorders following orthopedic surgical stress in elderly patients. BMC Geriatr. 2023;23(1):416. 10.1186/s12877-023-03989-w . Van Boxstael S, Peene L, Dylst D, et al. The effect of spinal anesthesia versus general anesthesia on perioperative muscle weakness in patients undergoing bilateral total hip arthroplasty: A single-center randomized clinical trial. Eur J Med Res. 2023;28(1):450. 10.1186/s40001-023-01435-6 . Sedlár M, Kudrnová Z, Erhart D, et al. Age and type of surgery predict early inflammatory response to hip trauma driven by interleukin-6 (IL-6). Arch Gerontol Geriatr. 2010;51(1):e1–6. 10.1016/j.archger.2009.06.006 . Akbari A, Moazen M, Babajafari S, et al. Acute or short-term effects of whey protein alone or along with carbohydrate on inflammation: A systematic review of clinical trials. Galen Med J. 2023;12:e2441. 10.31661/gmj.v12i.2441 . Issangya CE, Msuya D, Chilonga K et al. Perioperative serum albumin as a predictor of adverse outcomes in abdominal surgery: prospective cohort hospital based study in Northern Tanzania. BMC Surg. 2020;20(1):155. Published 2020 Jul 14. 10.1186/s12893-020-00820-w Niitsu M, Ichinose D, Hirooka T, et al. Effects of whey protein intake and rehabilitation combination on muscle strength and daily activities during the postoperative period in patients with hip fractures. Clin Nutr. 2016;35:943–9. Gümüş K, Aydın G. The effect of preoperative nutrition on postoperative CRP and albumin levels in patients undergoing laparoscopic surgery: A surgical nursing perspective. J Perianesth Nurs. 2020;35(6):592–6. 10.1016/j.jopan.2020.06.018 . Wong J, Tong D, De Silva Y, Abrishami A, Chung F. Development of the functional recovery index for ambulatory surgery and anesthesia. Anesthesiology. 2009;110(3):596–602. 10.1097/ALN.0b013e318197a16d . Stessel B, Hendrickx M, Pelckmans C, et al. One-month recovery profile and prevalence and predictors of quality of recovery after painful day case surgery: Secondary analysis of a randomized controlled trial. PLoS ONE. 2021;16(1):e0245774. 10.1371/journal.pone.0245774 . Published 2021 Jan 26. Le Bescond V, Petit-Phan J, Campfort M, et al. Validation of the QoR-15 postoperative recovery questionnaire and its association with quality of life three months after emergency surgery. Can J Anaesth. 2024. 10.1007/s12630-024-02722-4 . Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9059249","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":611625444,"identity":"122cc2d4-cac9-4bc4-b35f-06dd8dcad1c7","order_by":0,"name":"HÜMEYRA YÜKSEL","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA90lEQVRIiWNgGAWjYBACAwSTsYEhoQJIMzM3kKLlDEgLI9FaQLraoHrxAXOJ7MTHvHvs7PrZDzd+eDivNpq/HajlR8U2nFosZ+RuNuZ5lpw8syexWSJx2/HcGYcZGxh7ztzG7bAbudukeQ4wJxvcALoqcdux3AagFmbGNrxatv/mOVCfbA/WMudY7nwitGxj5jlw2M5AAqSloSZ3A0EtZ95ulpxz4HiCxBmgXxKOHcjdCNRyEK9fjudu/PDmQLU9f/vxhx9/1NTlzjt/+OCDHxW4tYAAEw8D0EkQ9mEweQCveiBg/MHAYA9l1xFSPApGwSgYBSMQAADwh2GFlVzhuQAAAABJRU5ErkJggg==","orcid":"","institution":"Erciyes University","correspondingAuthor":true,"prefix":"","firstName":"HÜMEYRA","middleName":"","lastName":"YÜKSEL","suffix":""},{"id":611625448,"identity":"22a3d88e-1d4b-4505-a9c0-f45ae66b728d","order_by":1,"name":"Mürüvvet BAŞER","email":"","orcid":"","institution":"Erciyes University","correspondingAuthor":false,"prefix":"","firstName":"Mürüvvet","middleName":"","lastName":"BAŞER","suffix":""}],"badges":[],"createdAt":"2026-03-07 14:53:19","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9059249/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9059249/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105410981,"identity":"472735e6-b398-40f1-96c3-15180b678a90","added_by":"auto","created_at":"2026-03-25 17:20:08","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":94806,"visible":true,"origin":"","legend":"\u003cp\u003eCONSORT Flow Diagram\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-9059249/v1/bd307772459f46880489ef1a.png"},{"id":105565747,"identity":"48e2f5db-3ec0-483f-8536-83b84db9848f","added_by":"auto","created_at":"2026-03-27 12:54:17","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1282353,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9059249/v1/ab26083d-fc0a-4832-bc04-ae5f19123079.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Preoperative Whey Protein Supplementation and Early Postoperative Outcomes in Older Adults Undergoing Total Hip Arthroplasty","fulltext":[{"header":"Highlights","content":"\u003cul\u003e\n\u003cli\u003ePreoperative whey protein supplementation did not significantly reduce early postoperative insulin resistance after baseline adjustment.\u003c/li\u003e\n\u003cli\u003eBaseline metabolic status was the main determinant of early postoperative insulin and HOMA-IR levels.\u003c/li\u003e\n\u003cli\u003eNo significant effects were observed on glucose, cortisol, CRP, albumin, or recovery quality.\u003c/li\u003e\n\u003cli\u003eA single preoperative whey protein dose may be insufficient to modify short-term postoperative metabolic responses.\u003c/li\u003e\n\u003cli\u003eNutritional optimization strategies may require longer or combined interventions to influence recovery outcomes.\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"1. Introduction","content":"\u003cp\u003eAging is associated with progressive physiological and metabolic changes that increase vulnerability to surgical stress and adversely affect postoperative recovery. In elderly individuals, age-related alterations in body composition, reduced muscle mass, and decreased metabolic reserve contribute to an increased risk of malnutrition, impaired immune function, delayed wound healing, and prolonged hospitalization following major surgical procedures. These factors highlight the critical importance of perioperative nutritional status in geriatric patients (\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). Previous studies have emphasized the importance of preoperative nutritional assessment in elderly surgical patients, demonstrating an association between poor nutritional status, increased postoperative complication risk, and prolonged recovery periods (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). Similarly, other research underscores the need for routine screening of surgical patients for malnutrition risk to inform both preoperative and postoperative nutritional management strategies (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTotal hip arthroplasty (THA) is one of the most frequently performed orthopedic procedures among elderly individuals and is widely recognized for its effectiveness in relieving pain, restoring joint function, and improving quality of life. However, elderly patients undergoing THA often present with multiple comorbidities and reduced physiological resilience, which may increase susceptibility to postoperative metabolic disturbances, inflammatory responses, and delayed recovery (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e \u003cp\u003ePreoperative fasting and surgical stress can exacerbate catabolic responses, resulting in increased insulin resistance, elevated stress hormone levels, and accelerated protein breakdown. In elderly patients, these metabolic alterations may negatively influence postoperative recovery and functional outcomes, emphasizing the need for effective nutritional strategies during the perioperative period (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWhey protein is a high-quality, rapidly digestible protein rich in essential amino acids and branched-chain amino acids, particularly leucine, which plays a key role in stimulating muscle protein synthesis. Due to its favorable absorption profile and metabolic effects, whey protein supplementation has been proposed as a potential strategy to support metabolic stability and recovery in surgical patients. However, evidence regarding the effects of preoperative whey protein supplementation on postoperative metabolic markers and recovery outcomes in elderly patients undergoing THA remains limited (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). A meta-analysis reported that whey protein supplementation moderately improved lower-limb muscle strength in older adults and was associated with changes in fasting insulin levels and HOMA-IR values (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Additionally, comprehensive reviews of the literature suggest that whey protein is a safe and potentially beneficial supplement for improving metabolic health in older adults without underlying renal disease, with evidence indicating possible improvements in insulin resistance, dyslipidemia, vascular function, blood pressure, and chronic low-grade inflammation (\u003cspan additionalcitationids=\"CR12\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTherefore, this study aims to evaluate the effects of preoperative whey protein supplementation on postoperative metabolic markers, including cortisol levels, insulin resistance, C-reactive protein, and albumin levels, as well as recovery outcomes in elderly patients undergoing total hip arthroplasty.\u003c/p\u003e"},{"header":"2. Method","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n\u003ch2\u003e2.1.Study Design and Setting\u003c/h2\u003e\n\u003cp\u003eThis study was conducted as a prospective, open-label, randomized controlled trial. Patients scheduled for total hip arthroplasty were admitted to the orthopedics and traumatology ward one day prior to surgery, and routine preoperative blood tests were performed. All patients were instructed to fast after midnight on the night before surgery and were scheduled as the first case of the day. Surgical procedures were performed under spinal anesthesia and lasted approximately two hours.\u003c/p\u003e\n\u003cp\u003eThe study was reported in accordance with the Consolidated Standards of Reporting Trials (CONSORT) guidelines for two-arm randomized controlled trials (\u003cspan class=\"CitationRef\"\u003e14\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n\u003ch2\u003e2.2.Sample Size Calculation\u003c/h2\u003e\n\u003cp\u003eAn a priori power analysis was conducted using G*Power software (version 3.1) to determine the required sample size. As no previous randomized studies had specifically evaluated the effects of preoperative whey protein supplementation in elderly patients undergoing total hip arthroplasty, the effect size was estimated based on a previously published randomized controlled trial examining the metabolic effects of preoperative nutritional loading in surgical patients (\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eBased on this estimation, a minimum sample size of 30 participants per group was required to achieve 90% statistical power with a two-sided alpha level of 0.05 and an assumed effect size of 0.215. Accordingly, 30 patients were allocated to the intervention group and 32 patients to the control group. A total of 62 patients who met the eligibility criteria were enrolled from the orthopedics and traumatology clinics of a public hospital in Turkey (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n\u003ch2\u003e2.3.Randomization\u003c/h2\u003e\n\u003cp\u003eEligible patients (n\u0026thinsp;=\u0026thinsp;62) were randomly assigned to either the intervention group or the control group using a computer-generated randomization sequence created through an online randomization tool (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.randomizer.org/\u003c/span\u003e\u003c/span\u003e). Randomization was performed at the time of hospital admission after confirmation of eligibility. This approach ensured that all eligible patients had an equal chance of being allocated to either group and minimized the risk of selection bias.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n\u003cp\u003e2.4.Outcomes Measurement\u003c/p\u003e\n\u003cp\u003eThe data for the study were collected using the Individual Demographic Form and the QoR-15T patient questionnaire. The Individual Demographic Form was created by the researchers and through a literature review (\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e) to record patients' socio-demographic data, as well as blood pressure, pulse, respiratory rate, SpO2 value, blood glucose, cortisol, CRP, albumin, and insulin resistance (HOMA-IR) levels. To assess insulin resistance, the HOMA-IR (Homeostasis Model Assessment of Insulin Resistance) equation (HOMA-IR\u0026thinsp;=\u0026thinsp;insulin (\u0026micro;U/mL) \u0026times; glucose (mg/dL) / 405) was used (\u003cspan class=\"CitationRef\"\u003e17\u003c/span\u003e). The QoR-15T patient questionnaire was developed by Myles PS (\u003cspan class=\"CitationRef\"\u003e18\u003c/span\u003e) and was validated for use in Turkish in 2022 (\u003cspan class=\"CitationRef\"\u003e19\u003c/span\u003e). The scale scores and subscale scores are compared based on gender, ASA PS, smoking, alcohol consumption, education level, and the scope of surgery. The scale consists of two sections with a total of 15 questions. The first section includes 10 questions regarding how the patient felt during the first 24 hours, while the second section contains five questions related to the patient's experiences in the last 24 hours. This scale is tested by comparing the preoperative and postoperative groups. The measurement is performed using a Visual Analog Scale (VAS) of 100 mm. According to the VAS, scores of 70 mm or lower are considered poor, while scores above 70 mm indicate good postoperative recovery quality. The Cronbach's alpha value for the scale was found to be 0.863. In our study, however, the Cronbach's alpha value of the scale was 0.761.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.5.Inclusion criteria\u003c/strong\u003e: Individuals aged 50\u0026ndash;70 years who underwent Total Hip Arthroplasty (THA) under spinal anesthesia, had a body mass index (BMI)\u0026thinsp;\u0026lt;\u0026thinsp;40 kg/m\u0026sup2;, and were classified as ASA physical status I, II, or III according to the American Society of Anesthesiologists Physical Status Classification System were included in the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.6.Exclusion criteria\u003c/strong\u003e: Individuals with communication difficulties; diagnosed hepatic, renal, endocrine, gastric, neurological, or psychiatric disorders; malnutrition defined as an NRS-2002 score\u0026thinsp;\u0026ge;\u0026thinsp;3; known allergy to whey protein; or lactose intolerance were excluded from the study. Verbal and written informed consent was obtained from all eligible patients prior to participation, and a written informed consent form was provided in the patient\u0026rsquo;s room.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n\u003ch2\u003e2.7.Variables of the Study\u003c/h2\u003e\n\u003cp\u003e\u003cstrong\u003eIndependent variables\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAge, gender, marital status, educational level, presence of chronic diseases, and duration of surgery.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eControl variable\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOral whey protein intake.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDependent variables\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eVital signs (blood pressure, pulse, respiratory SpO2 value), blood glucose, cortisol, CRP, albumin, insulin resistance levels, and postoperative recovery quality scale score.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n\u003ch2\u003e2.8.Intervention Group\u003c/h2\u003e\n\u003cp\u003eIn this study, based on the relevant literature (\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e) and expert opinions (dietitian, anesthesiologist, and orthopedic surgeon), patients in the intervention group were instructed to consume 600 mL of an oral whey protein solution 6 hours before surgery.\u003c/p\u003e\n\u003cp\u003eThe whey protein solution used in the study was prepared by the researcher by dissolving 60 g of whey protein powder (Katkı D\u0026uuml;nyası\u0026reg;, Turkey) in 600 mL of bottled water. The resulting mixture provided approximately 200 kcal and was prepared at room temperature. The solution was administered at the patient\u0026rsquo;s bedside and consumed intermittently over a one-hour period, starting 6 hours before surgery.\u003c/p\u003e\n\u003cp\u003eData were collected at three time points: 24 hours before surgery, immediately before surgery, and 24 hours after surgery. For biochemical measurements, 3 mL of venous blood was drawn into appropriate biochemical and hemogram tubes to assess blood glucose, cortisol, albumin, C-reactive protein (CRP), and insulin resistance. All samples were analyzed in the hospital laboratory, and the results were recorded in the Physiological Measurements Table. Postoperative recovery quality was assessed using the QoR-15T questionnaire 24 hours after surgery (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n\u003ch2\u003e2.9.Control Gruop\u003c/h2\u003e\n\u003cp\u003ePatients in the control group were instructed to consume only 600 mL of water intermittently over a one-hour period, starting 6 hours before surgery. Data collection time points were identical to those of the intervention group: 24 hours before surgery, immediately before surgery, and 24 hours after surgery.\u003c/p\u003e\n\u003cp\u003eFor biochemical measurements, 3 mL of venous blood was collected to evaluate blood glucose, cortisol, albumin, C-reactive protein (CRP), and insulin resistance. Laboratory results were recorded in the Physiological Measurements Table. The QoR-15T questionnaire was administered 24 hours after surgery to assess postoperative recovery quality (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u0026nbsp;\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eApplication Steps for the Intervention and Control Groups\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eApplication Time\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eIntervention Group\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eControl Group\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e24 Hours Before Surgery\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e✓ Obtain verbal and written informed consent✓ Measure vital signs (blood pressure, pulse, respiratory rate, SpO₂)✓ Measure blood glucose levels✓ Measure cortisol, albumin, CRP, and insulin resistance levels\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e✓ Obtain verbal and written informed consent✓ Measure vital signs (blood pressure, pulse, respiratory rate, SpO₂)✓ Measure blood glucose levels✓ Measure cortisol, albumin, CRP, and insulin resistance levels\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e6 Hours Before Surgery\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e✓ Consume 600 mL whey protein solution\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e✓ Consume 600 mL water\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eImmediately Before Surgery\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e✓ Measure vital signs (blood pressure, pulse, respiratory rate, SpO₂)✓ Measure blood glucose levels✓ Measure cortisol, albumin, CRP, and insulin resistance levels\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e✓ Measure vital signs (blood pressure, pulse, respiratory rate, SpO₂)✓ Measure blood glucose levels✓ Measure cortisol, albumin, CRP, and insulin resistance levels\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e24 Hours After Surgery\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e✓ Measure vital signs (blood pressure, pulse, respiratory rate, SpO₂)✓ Measure blood glucose levels✓ Measure cortisol, albumin, CRP, and insulin resistance levels✓ Administer QoR-15T questionnaire\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e✓ Measure vital signs (blood pressure, pulse, respiratory rate, SpO₂)✓ Measure blood glucose levels✓ Measure cortisol, albumin, CRP, and insulin resistance levels✓ Administer QoR-15T questionnaire\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\n\u003ch2\u003e2.10.Statistical Analysis\u003c/h2\u003e\n\u003cp\u003eCategorical variables were summarized as numbers and percentages, whereas continuous variables were expressed as means and standard deviations or medians with interquartile ranges, depending on data distribution. Normality of continuous variables was assessed using the Shapiro\u0026ndash;Wilk test.\u003c/p\u003e\n\u003cp\u003eAll analyses were performed according to the intention-to-treat (ITT) principle to preserve the benefits of randomization and minimize potential bias. Participants were analyzed in the groups to which they were originally assigned, regardless of adherence to the intervention protocol.\u003c/p\u003e\n\u003cp\u003eBaseline characteristics between the whey protein supplementation group and the control group were compared to confirm successful randomization. Between-group comparisons of continuous variables were conducted using independent-samples t-tests or Mann\u0026ndash;Whitney U tests, as appropriate, while categorical variables were compared using chi-square or Fisher\u0026rsquo;s exact tests.\u003c/p\u003e\n\u003cp\u003eTo evaluate postoperative metabolic recovery and inflammatory response over time, repeated-measures analyses were performed across predefined time points (preoperative baseline and postoperative follow-up assessments). Group \u0026times; time interaction effects were specifically examined to assess whether changes in metabolic markers differed between the intervention and control groups.\u003c/p\u003e\n\u003cp\u003eWithin-group changes over time were analyzed using paired t-tests or Wilcoxon signed-rank tests, whereas between-group differences at each postoperative time point were evaluated using independent-samples tests. For outcomes measured repeatedly over time, generalized linear mixed-effects models were additionally applied to account for intra-individual correlations and missing-at-random data patterns.\u003c/p\u003e\n\u003cp\u003ePrespecified subgroup analyses were conducted according to age, sex, and baseline nutritional and metabolic status to explore potential effect modification. Interaction terms were tested to assess the consistency of the intervention effect across subgroups.\u003c/p\u003e\n\u003cp\u003eEffect sizes and relative changes were reported alongside p values to enhance the clinical interpretation of statistically significant findings. All statistical tests were two-sided, and a p value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\n\u003ch2\u003e2.11.Ethical Consideration\u003c/h2\u003e\n\u003cp\u003eThe study protocol was approved by the Erciyes University Research Ethics Committee with the decision number: 2023\\132 and registered in ClinicalTrials.gov with the identification number NCT06307782. In addition, verbal and written permissions were obtained from the patients included in the research. The data were collected by the researchers and stored securely. The study was conducted according to the guidelines of the Declaration of Helsinki.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3. Results","content":"\u003cp\u003eIn the intervention group, 53.3% of patients were male, while 50% of the control group were female. Regarding education level, 46.7% of patients in the intervention group had completed secondary education, compared to 50% of patients in the control group who had completed primary education. All participants were married, and spinal anesthesia was used for all surgeries. There were no statistically significant differences between the intervention and control groups in terms of gender, education level, presence or type of chronic diseases, ASA score, BMI, or duration of surgery (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of Some Characteristics of Patients in the Intervention and Control Groups\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eGender\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIntervention Group (n\u0026thinsp;=\u0026thinsp;30)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eControl Group (n\u0026thinsp;=\u0026thinsp;32)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTest a,b\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (46.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eⷌ\u0026sup2;= 0.069\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.793\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16 (53.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEducation Level\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIlliterate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (3.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (6.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eⷌ\u0026sup2;= 0.734\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.865\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrimary Education\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13 (43.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSecondary Education\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (46.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12 (37.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHigher Education\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (6.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (6.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eChronic Disease\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePresent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20 (66.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19 (59.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eⷌ\u0026sup2;= 0.353\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.553\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAbsent\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13 (40.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eType of Chronic Disease\u003c/b\u003e c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHypertension\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18 (75.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17 (68.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eⷌ\u0026sup2;= 1.086\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.581\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeart Failure\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (25.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (28.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChronic Obstructive Pulmonary Disease\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 (4.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eASA Score\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eII\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20 (62.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eⷌ\u0026sup2;= 0.984\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.321\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIII\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (50.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12 (37.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003ex̄ \u0026plusmn; sd\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eMedian [IQR]\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003ex̄ \u0026plusmn; sd\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eMedian [IQR]\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBMI (kg/m\u0026sup2;)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e28.70\u0026thinsp;\u0026plusmn;\u0026thinsp;2.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29 [3.3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e28.28\u0026thinsp;\u0026plusmn;\u0026thinsp;2.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e28.5 [4]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eOperation Time (min)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e131.00\u0026thinsp;\u0026plusmn;\u0026thinsp;14.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e120 [30]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e128.43\u0026thinsp;\u0026plusmn;\u0026thinsp;13.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e120 [30]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eMann-Whitney U test (Z-table value)\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe mean blood glucose level 24 hours before surgery was similar between the intervention (112 mg/dL) and control groups (123 mg/dL) (p\u0026thinsp;=\u0026thinsp;0.443). There was no significant difference in glucose levels between groups at any measured time point.\u003c/p\u003e \u003cp\u003eHowever, significant differences were observed in insulin and HOMA-IR values. Preoperatively, the mean insulin level was lower in the intervention group (6.9 \u0026micro;U/mL) compared to the control group (26.6 \u0026micro;U/mL) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and 24 hours postoperatively, insulin remained significantly lower in the intervention group (12.2 \u0026micro;U/mL vs. 28.4 \u0026micro;U/mL, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Similarly, HOMA-IR values were significantly lower in the intervention group both preoperatively (1.6 vs. 6.3, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and 24 hours after surgery (3.7 vs. 8.4, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), indicating improved insulin sensitivity following preoperative whey protein supplementation (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of Glucose, Insulin, and HOMA-IR Values between the Intervention and Control Groups.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eİntervetion Group\u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;30)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eControl Group\u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;32)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTest*\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\stackrel{-}{\\mathbf{X}}\\pm\\mathbf{S}.\\mathbf{S}.\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eMedian [IQR]\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\stackrel{-}{\\mathbf{X}}\\pm\\mathbf{S}.\\mathbf{S}.\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003eMedian [IQR]\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eGlucose(mg/dL)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24 hours before \u003csup\u003e(1)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e113.30\u0026thinsp;\u0026plusmn;\u0026thinsp;25.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e112 [42.5]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e121.53\u0026thinsp;\u0026plusmn;\u0026thinsp;22.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e123 [40.5]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003et= -1.341\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.185\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePreoperative \u003csup\u003e(2)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e97.50\u0026thinsp;\u0026plusmn;\u0026thinsp;16.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e97 [24.3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e97.13\u0026thinsp;\u0026plusmn;\u0026thinsp;13.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e97 [15.5]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eZ= -0.261\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.794\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24 hours after \u003csup\u003e(3)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e121.37\u0026thinsp;\u0026plusmn;\u0026thinsp;15.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e120 [21.5]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e125.00\u0026thinsp;\u0026plusmn;\u0026thinsp;20.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e126 [26]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003et= -0.772\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.443\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTest\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eDifference\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eF\u0026thinsp;=\u0026thinsp;18.605, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003cp\u003e[2\u0026thinsp;\u0026minus;\u0026thinsp;1,3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eχ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;29.688, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003cp\u003e[2\u0026thinsp;\u0026minus;\u0026thinsp;1,3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eInsulin(\u0026micro;IU/mL)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24 hours before \u003csup\u003e(1)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30.74\u0026thinsp;\u0026plusmn;\u0026thinsp;12.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e32 [24.1]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e31.32\u0026thinsp;\u0026plusmn;\u0026thinsp;10.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e33.9 [17.4]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eZ= -0.106\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.916\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePreoperative \u003csup\u003e(2)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.60\u0026thinsp;\u0026plusmn;\u0026thinsp;3.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.9 [5.4]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e26.20\u0026thinsp;\u0026plusmn;\u0026thinsp;8.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e26.6 [16.4]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003et= -10.892\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24 hours after \u003csup\u003e(3)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.19\u0026thinsp;\u0026plusmn;\u0026thinsp;3.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12.2 [5.7]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e27.74\u0026thinsp;\u0026plusmn;\u0026thinsp;10.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e28.4 [16.7]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003et= -8.385\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTest\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eDifference\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eχ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;58.067, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003cp\u003e[1\u0026ndash;2,3] [2\u0026ndash;3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eF\u0026thinsp;=\u0026thinsp;19.233, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003cp\u003e[1\u0026ndash;2,3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHOMA-IR\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24 hours before \u003csup\u003e(1)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.85\u0026thinsp;\u0026plusmn;\u0026thinsp;4.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.3 [7.9]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.45\u0026thinsp;\u0026plusmn;\u0026thinsp;3.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9.3 [5.5]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003et= -0.561\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.577\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePreoperative \u003csup\u003e(2)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.88\u0026thinsp;\u0026plusmn;\u0026thinsp;1.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.6 [1.7]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.22\u0026thinsp;\u0026plusmn;\u0026thinsp;2.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6.3 [3.7]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003et= -10.264\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24 hours after \u003csup\u003e(3)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.69\u0026thinsp;\u0026plusmn;\u0026thinsp;1.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.7 [2.2]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.46\u0026thinsp;\u0026plusmn;\u0026thinsp;3.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8.4 [4.7]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003et= -8.048\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTest\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eDifference\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eF\u0026thinsp;=\u0026thinsp;81.353, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003cp\u003e[1\u0026ndash;2,3] [2\u0026ndash;3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eF\u0026thinsp;=\u0026thinsp;37.952, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003cp\u003e[2\u0026thinsp;\u0026minus;\u0026thinsp;1,3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eRepeated Measures Test (F-table value),Independent Sample t-test (t-table value),Mann-Whitney U Test (Z-table value),Friedman Test (χ\u0026sup2;-table value)\u003c/p\u003e \u003cp\u003eNo significant differences were observed in cortisol levels between the intervention and control groups at any measured time point (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eAlbumin levels were similar between groups 24 hours before surgery (intervention: 38.5 g/L vs. control: 37.5 g/L, p\u0026thinsp;=\u0026thinsp;0.806). Postoperatively, albumin was slightly higher in the control group (37 g/L vs. 36 g/L, p\u0026thinsp;=\u0026thinsp;0.017).\u003c/p\u003e \u003cp\u003eCRP levels increased in both groups after surgery, with significantly higher values in the intervention group at 24 hours postoperatively (59.5 mg/L vs. 43.9 mg/L, p\u0026thinsp;=\u0026thinsp;0.019). No significant differences were found preoperatively (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEffect Size of Preoperative Whey Protein Supplementation on Variables (Cohen\u0026rsquo;s d and Partial η\u0026sup2;)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeğişken\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCohen\u0026rsquo;s d (\u0026asymp;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePartial η\u0026sup2; (\u0026asymp;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eYorum\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGlucose(mg/dL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.20\u0026ndash;0.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSmall effect\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInsulin (\u0026micro;IU/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.5\u0026ndash;1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.60 civarı\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eVery large effect\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHOMA-IR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.3\u0026ndash;1.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.55\u0026ndash;0.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eVery large effect\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThis table was created to evaluate the effect size of preoperative whey protein supplementation on metabolic parameters. According to the analysis results, preoperative whey protein supplementation had a large effect size on insulin and HOMA-IR levels (Cohen\u0026rsquo;s d\u0026thinsp;\u0026gt;\u0026thinsp;1.0; partial η\u0026sup2; \u0026gt; 0.50). In contrast, a small effect size was observed for glucose levels.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of Cortisol, Albumin, and CRP Values Between the Intervention and Control Groups\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"13\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" morerows=\"1\" nameend=\"c3\" namest=\"c1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c7\" namest=\"c4\"\u003e \u003cp\u003eİntervetion Group\u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;30)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c12\" namest=\"c8\"\u003e \u003cp\u003eControl Group\u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;32)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c13\"\u003e \u003cp\u003eTest*\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\stackrel{-}{\\mathbf{X}}\\pm\\mathbf{S}.\\mathbf{S}.\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e\u003cb\u003eMedian [IQR]\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\stackrel{-}{\\mathbf{X}}\\pm\\mathbf{S}.\\mathbf{S}.\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c12\" namest=\"c10\"\u003e \u003cp\u003e\u003cb\u003eMedian [IQR]\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"1\" nameend=\"c13\" namest=\"c13\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"13\" nameend=\"c13\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCortisol (\u0026micro;g/dL)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e24 hours before \u003csup\u003e(1)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c5\" namest=\"c3\"\u003e \u003cp\u003e9.62\u0026thinsp;\u0026plusmn;\u0026thinsp;5.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e8.2 [8.5]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e8.57\u0026thinsp;\u0026plusmn;\u0026thinsp;3.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003e7.9 [6.9]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e \u003cp\u003eZ= -0.331\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.741\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003ePreoperative \u003csup\u003e(2)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c5\" namest=\"c3\"\u003e \u003cp\u003e12.19\u0026thinsp;\u0026plusmn;\u0026thinsp;4.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e12.5 [8.3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e13.28\u0026thinsp;\u0026plusmn;\u0026thinsp;4.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003e14.4 [6.9]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e \u003cp\u003et= -0.938\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.352\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e24 hours after \u003csup\u003e(3)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c5\" namest=\"c3\"\u003e \u003cp\u003e12.10\u0026thinsp;\u0026plusmn;\u0026thinsp;5.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e12.4 [8.4]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e11.89\u0026thinsp;\u0026plusmn;\u0026thinsp;3.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003e12.4 [3.2]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e \u003cp\u003et\u0026thinsp;=\u0026thinsp;0.177\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.860\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTest\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eDifference\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c7\" namest=\"c3\"\u003e \u003cp\u003eχ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;5.067, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.079\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c11\" namest=\"c8\"\u003e \u003cp\u003eF\u0026thinsp;=\u0026thinsp;32.629, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003cp\u003e[2\u0026thinsp;\u0026minus;\u0026thinsp;1,3] [1\u0026ndash;3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"13\" nameend=\"c13\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAlbumin(mg/L)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24 hours before \u003csup\u003e(1)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e38.17\u0026thinsp;\u0026plusmn;\u0026thinsp;4.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e38.5 [7]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e38.88\u0026thinsp;\u0026plusmn;\u0026thinsp;4.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003e37.5 [6.3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c13\" namest=\"c11\"\u003e \u003cp\u003et\u0026thinsp;=\u0026thinsp;0.246\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.806\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePreoperative \u003csup\u003e(2)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e35.57\u0026thinsp;\u0026plusmn;\u0026thinsp;4.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e36.5 [7]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e36.44\u0026thinsp;\u0026plusmn;\u0026thinsp;3.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003e36.5 [3.8]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c13\" namest=\"c11\"\u003e \u003cp\u003et= -0.812\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.420\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24 hours after \u003csup\u003e(3)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e35.20\u0026thinsp;\u0026plusmn;\u0026thinsp;3.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e36 [5.3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e37.65\u0026thinsp;\u0026plusmn;\u0026thinsp;4.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003e37 [5]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c13\" namest=\"c11\"\u003e \u003cp\u003et= -2.460\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.017\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTest\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eDifference\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c6\" namest=\"c2\"\u003e \u003cp\u003eF\u0026thinsp;=\u0026thinsp;41.293, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003cp\u003e[1\u0026ndash;2,3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c10\" namest=\"c7\"\u003e \u003cp\u003eF\u0026thinsp;=\u0026thinsp;5.355, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.007\u003c/p\u003e \u003cp\u003e[2\u0026thinsp;\u0026minus;\u0026thinsp;1,3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c13\" namest=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"13\" nameend=\"c13\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCRP (g/L)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24 hours before \u003csup\u003e(1)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e12.88\u0026thinsp;\u0026plusmn;\u0026thinsp;15.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e4.2 [15.6]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e13.41\u0026thinsp;\u0026plusmn;\u0026thinsp;11.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003e9.1 [21.9]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c13\" namest=\"c11\"\u003e \u003cp\u003eZ= -0.641\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.522\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePreoperative \u003csup\u003e(2)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e28.84\u0026thinsp;\u0026plusmn;\u0026thinsp;23.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e22.2 [34.6]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e27.88\u0026thinsp;\u0026plusmn;\u0026thinsp;14,66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003e26.6 [21.7]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c13\" namest=\"c11\"\u003e \u003cp\u003eZ= -0.704\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.481\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24 hours after \u003csup\u003e(3)\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e59.54\u0026thinsp;\u0026plusmn;\u0026thinsp;30.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e61 [48.3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e43.94\u0026thinsp;\u0026plusmn;\u0026thinsp;18.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003e42 [28.2]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c13\" namest=\"c11\"\u003e \u003cp\u003et\u0026thinsp;=\u0026thinsp;2.426\u003c/p\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.019\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eTest\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eDifference\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c6\" namest=\"c2\"\u003e \u003cp\u003eχ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;60.000, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003cp\u003e[1\u0026ndash;2,3] [2\u0026ndash;3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c10\" namest=\"c7\"\u003e \u003cp\u003eχ\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;56.250, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003cp\u003e[1\u0026ndash;2,3] [2\u0026ndash;3]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c13\" namest=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eRepeated Measures Test (F-table value),Independent Sample t-test (t-table value),Mann-Whitney U Test (Z-table value),Friedman Test (χ\u0026sup2;-table value)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eANCOVA-Adjusted Postoperative Insulin and HOMA-IR Levels- Adjustment for baseline (preoperative) values\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOutcome\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCovariate (Baseline)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eEffect\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eF value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eInsulin (24 h postoperative)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePreoperative insulin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup (Whey vs Control)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.327\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBaseline insulin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e155.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHOMA-IR (24 h postoperative)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePreoperative HOMA-IR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup (Whey vs Control)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.969\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBaseline HOMA-IR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e94.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eANCOVA analyses were performed to compare postoperative insulin and HOMA-IR levels between groups while adjusting for baseline (preoperative) values. Group was entered as a fixed factor and baseline values as covariates. After adjustment, no statistically significant group effect was observed for postoperative insulin (F\u0026thinsp;=\u0026thinsp;0.98, p\u0026thinsp;=\u0026thinsp;0.327) or HOMA-IR levels (F\u0026thinsp;=\u0026thinsp;0.002, p\u0026thinsp;=\u0026thinsp;0.969) (Table X). Baseline insulin and HOMA-IR values were strong predictors of postoperative metabolic outcomes (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001 for both).\u003c/p\u003e \u003cp\u003eThe overall QoR-15T scores decreased in both groups after surgery. Preoperatively, the intervention group had higher scores compared to the control group (84.8\u0026thinsp;\u0026plusmn;\u0026thinsp;6.54 vs. 81.5\u0026thinsp;\u0026plusmn;\u0026thinsp;4.33, p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), while no significant difference was observed postoperatively (74.2\u0026thinsp;\u0026plusmn;\u0026thinsp;3.75 vs. 74.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.99, p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Significant differences were found in individual dimensions, including rest, sleep quality, personal care, comfort and control, and overall well-being (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), with post-surgery scores generally lower than preoperative scores.\u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThe findings of this study, which aimed to determine the effects of preoperatively administered whey protein on postoperative cortisol, insulin resistance, CRP, albumin levels, and recovery quality, are discussed below in light of the literature. Although unadjusted analyses suggested lower postoperative insulin and HOMA-IR levels in the whey protein group, ANCOVA analyses adjusting for baseline metabolic values indicated that these differences were no longer statistically significant. This suggests that baseline metabolic status plays a dominant role in determining early postoperative insulin resistance. Given the short postoperative follow-up period of 24 hours, the metabolic effects of a single preoperative whey protein dose may be insufficient to overcome pre-existing insulin resistance in elderly patients undergoing total hip arthroplasty.\u003c/p\u003e \u003cp\u003eSurgical trauma triggers inflammatory, metabolic, and neurohormonal responses. Metabolic disorders, such as insulin resistance, develop after elective surgical procedures and persist for approximately five days postoperatively (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e). In addition to calories and carbohydrates, protein plays a crucial role in postoperative recovery as it promotes anabolism, slows muscle catabolism, and shortens the inflammatory phase. Whey protein can be absorbed and utilized by skeletal muscle during stress. Moreover, it stimulates protein synthesis due to its high content of essential amino acids, particularly branched-chain amino acids, which are characterized by high digestibility and rapid absorption in the small intestine (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eNevertheless, whey protein is classified as a rapidly digestible protein because it can be readily absorbed and utilized by skeletal muscle during stress and contains essential amino acids, particularly branched-chain amino acids, which are highly digestible and rapidly absorbed in the small intestine (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e). Adequate protein intake plays a significant role in postoperative recovery by promoting anabolism, minimizing protein deficits and muscle catabolism, and potentially attenuating the inflammatory response (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eStudies involving whey protein administration (\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e) have reported a reduction in patients' blood glucose levels. However, in this study, whey protein was found to have no significant effect on blood glucose levels. Proteins and amino acids found in adequate protein content can reduce insulin response in certain clinical conditions such as obesity and type II diabetes. Whey protein, however, is rich in essential amino acids, which are key regulators of this response, and has been shown to have beneficial effects on HOMA-IR (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e). In a study by Onalan et al., which investigated the effects of preoperative oral carbohydrate solution (OCS) administration on postoperative insulin resistance and patient comfort in elective laparoscopic cholecystectomy, OCS was reported to reduce insulin resistance (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e). Similarly, Yuan et al. found that administering a preoperative orally enzyme-hydrolyzed rice flour solution to patients three hours before laparoscopic cholecystectomy significantly reduced postoperative insulin resistance (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e). Swanfelt et al. reported that when patients were given a carbohydrate-rich beverage preoperatively, whole-body protein balance was better maintained, and insulin\u0026rsquo;s suppressive effect on endogenous glucose release was preserved more effectively (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn our study, HOMA-IR levels were significantly reduced in the group consuming whey protein, demonstrating its effect on insulin resistance. Additionally, 24 hours postoperatively, the HOMA-IR values of patients who consumed whey protein were found to be approximately twice as low as those who consumed only water. Moreover, postoperative insulin resistance remained lower in the whey protein group, with their HOMA-IR values being lower than those in the control group but still above the normal threshold of 2.5 mg/dL. These findings suggest that preoperative administration of carbohydrates, a carbohydrate-whey protein mixture, or carbohydrate-containing fluids can positively impact patients by enhancing satiety and reducing insulin resistance\u003c/p\u003e \u003cp\u003eIn two different studies conducted with orthopedic and THA patients, cortisol levels were found to remain unchanged and within the normal range (\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e). Similarly, in our study, whey protein administration in the intervention group did not affect cortisol levels. However, since cortisol values remained within the normal range, it can be interpreted that surgical stress did not develop in these patients.\u003c/p\u003e \u003cp\u003eC-reactive protein (CRP) is a widely recognized inflammatory marker, and increases in its plasma concentration correspond to heightened systemic inflammation. In elderly patients undergoing total hip arthroplasty, CRP levels typically rise postoperatively, peaking around the second postoperative day (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn a meta-analysis by Akbari et al. evaluating the acute and short-term effects of whey protein supplementation, either alone or in combination with carbohydrates, on inflammatory outcomes, 25 randomized controlled trials were included. The authors reported that whey protein, with or without carbohydrates, did not significantly influence inflammatory markers in the short term (\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e). Consistent with these findings, our study also demonstrated no significant effect of preoperative whey protein supplementation on postoperative CRP levels, which may be attributable to the dominance of the acute surgical inflammatory response and the limited duration of postoperative follow-up.\u003c/p\u003e \u003cp\u003eAlbumin is a well-known marker of protein metabolism, which is often disrupted following trauma such as surgery, sepsis, or burns. The underlying pathophysiology may involve impaired hepatic albumin synthesis in the early postoperative phase, increased basal energy expenditure, and depletion of up to 20% of the body's protein stores. Additionally, capillary leakage, a common feature in sepsis and surgery, leads to albumin sequestration in the third space (\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e).\u003c/p\u003e \u003cp\u003ePlasma osmotic pressure and serum albumin levels are essential for maintaining physiological functions and serve as key indices for assessing a patient\u0026rsquo;s nutritional status and prognosis. A low serum albumin concentration reduces plasma colloid osmotic pressure and increases the incidence of pleural effusion (\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e). In one study, a carbohydrate solution mixed with 9 grams of whey protein was administered to patients three hours before surgery. However, no significant difference was observed in albumin levels between the preoperative and postoperative periods (\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e). Similarly, G\u0026uuml;m\u0026uuml;ş and Aydın reported that preoperative oral carbohydrate solution administration had no effect on postoperative albumin levels in patients undergoing laparoscopic surgery (\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e). A study from Northern Tanzania involving patients undergoing major abdominal surgery found that a greater decline in albumin levels was associated with a sixfold increase in the risk of surgical site infections, delayed wound healing, and higher 30-day mortality (adjusted odds ratio: 6.68; 95% CI: 1.59 to 28.09) (\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn our study, whey protein did not result in a significant difference in albumin levels between groups, and albumin concentrations remained within normal limits in both groups. However, considering that protein catabolism exceeds protein anabolism and may lead to decreased postoperative serum albumin concentrations, it can be suggested that preoperative whey protein intake in elderly patients undergoing THA supports nutritional status and helps maintain postoperative serum albumin levels.\u003c/p\u003e \u003cp\u003eQuality of Recovery (QoR) encompasses various aspects of a patient\u0026rsquo;s daily life after discharge, including physical, psychological, and social well-being, making it a subjective patient experience (\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e). In a study conducted with painful day-case surgical patients, the postoperative recovery profile over four weeks was found to be low to moderate in the short term (postoperative day 7) and long term (postoperative day 28) (\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e). In a study by Bescond et al., which aimed to validate the QoR-15 scale for emergency surgery and assess its relationship with postoperative three-month quality of life, a significant difference was observed between early postoperative recovery measured 24 hours after surgery and the QoR-15T score assessed two months later (\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e). In our study, oral whey protein administration in THA patients did not significantly affect the quality of recovery, and the assessment of the scale 24 hours postoperatively resulted in a lower total QoR score.\u003c/p\u003e \u003cp\u003eThe primary strength of this study is that it is the first to demonstrate the effects of preoperative whey protein supplementation on postoperative metabolic recovery and healing in elderly patients. Furthermore, it has been shown to be associated with improved nutritional outcomes, suppression of the acute-phase inflammatory response, and preservation of muscle strength in orthopedic patients. However, this study has certain limitations. The postoperative observation period was limited to 24 hours, which prevented assessment of the long-term effects of preoperative whey protein supplementation; a follow-up study has been planned by the researchers to evaluate these long-term outcomes. Moreover, as this was a single-center study, the generalizability of the protocol to other hospitals may be limited.\u003c/p\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eIn this randomized controlled trial, preoperative whey protein supplementation did not significantly improve early postoperative metabolic or inflammatory outcomes after adjustment for baseline values. Baseline metabolic status appeared to be the primary determinant of early postoperative insulin resistance.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eDeclaration of competing interest:\u003c/h2\u003e \u003cp\u003eThe authors declare no conflict of interest.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003eThis research was supported by Erciyes University Scientific Research Institution.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eHY and MB designed and conducted the study. HY performed the statistical analysis, interpreted the findings, and prepared the first draft. MB provided statistical expertise. HY and MB interpreted the results, critically reviewed the draft, and contributed intellectual content. MB supervised the study. All authors are fully responsible for the analysis and interpretation of the data, have read, and approved the final draft.\u003c/p\u003e\u003ch2\u003eAcknowledgments:\u003c/h2\u003e \u003cp\u003eWe thank Do\u0026ccedil;.Dr. Osman \u0026Ccedil;İLOĞLU and all participants for their cooperation in this study.\u003c/p\u003e\u003ch2\u003eData availability\u003c/h2\u003e \u003cp\u003eData described in the manuscript and analytic code will be made available upon request pending application and approval.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eYılmaz B, G\u0026uuml;nel Z. Malnutrition in the elderly population: causes and consequences. In: \u0026Ccedil;ağıran İH, ed. \u003cem\u003eInternational Research in Nutrition and Dietetics II\u003c/em\u003e. 2024:160\u0026ndash;166.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu L, Zhao F, Zha G, Zheng X, Yang G, Xu S. 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Validation of the QoR-15 postoperative recovery questionnaire and its association with quality of life three months after emergency surgery. Can J Anaesth. 2024. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s12630-024-02722-4\u003c/span\u003e\u003cspan address=\"10.1007/s12630-024-02722-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-orthopaedic-surgery-and-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"josr","sideBox":"Learn more about [Journal of Orthopaedic Surgery and Research](http://josr-online.biomedcentral.com)","snPcode":"13018","submissionUrl":"https://submission.nature.com/new-submission/13018/3","title":"Journal of Orthopaedic Surgery and Research","twitterHandle":"@MSKmedBMC","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Whey protein, total hip arthroplasty, elderly patients, insulin resistance, metabolic markers, postoperative recovery","lastPublishedDoi":"10.21203/rs.3.rs-9059249/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9059249/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eSurgical stress induces metabolic and inflammatory responses that may contribute to postoperative insulin resistance and delayed recovery, particularly in older adults. Preoperative nutritional optimization strategies have been proposed to improve perioperative metabolic stability.\u003c/p\u003e\u003ch2\u003eObjective\u003c/h2\u003e \u003cp\u003eThis randomized controlled trial aimed to evaluate the effects of preoperative whey protein supplementation on early postoperative metabolic markers and recovery quality in older adults undergoing total hip arthroplasty.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eSixty-two patients aged 50\u0026ndash;70 years scheduled for total hip arthroplasty under spinal anesthesia were randomly assigned to either the intervention group (n\u0026thinsp;=\u0026thinsp;30), who received 600 mL of oral whey protein solution six hours before surgery, or the control group (n\u0026thinsp;=\u0026thinsp;32), who received 600 mL of water. Blood samples were collected 24 hours before surgery, immediately before surgery, and 24 hours postoperatively to measure glucose, insulin, HOMA-IR, cortisol, albumin, and C-reactive protein levels. Postoperative recovery quality was assessed using the QoR-15T scale. Analyses were performed using intention-to-treat principles. Between-group comparisons were adjusted for baseline metabolic values using ANCOVA.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eUnadjusted analyses indicated lower insulin and HOMA-IR levels in the whey protein group. However, after adjustment for baseline values, no statistically significant group effect was observed for postoperative insulin (F\u0026thinsp;=\u0026thinsp;0.98, p\u0026thinsp;=\u0026thinsp;0.327) or HOMA-IR (F\u0026thinsp;=\u0026thinsp;0.969, p\u0026thinsp;=\u0026thinsp;0.002) levels. No significant differences were observed between groups in glucose, cortisol, CRP, albumin levels, or postoperative recovery quality.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003ePreoperative whey protein supplementation did not significantly improve early postoperative metabolic or inflammatory outcomes after adjustment for baseline metabolic status. Early postoperative insulin resistance appears to be primarily influenced by pre-existing metabolic conditions rather than a single preoperative whey protein dose.\u003c/p\u003e","manuscriptTitle":"Preoperative Whey Protein Supplementation and Early Postoperative Outcomes in Older Adults Undergoing Total Hip Arthroplasty","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-25 17:19:53","doi":"10.21203/rs.3.rs-9059249/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-08T02:43:13+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-07T07:34:47+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-02T14:47:39+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-26T15:50:17+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"61062010652795607665761201328916779329","date":"2026-03-26T04:39:02+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"321211521155826751102978767557726721271","date":"2026-03-26T01:06:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"229847715762276379753788652716332743117","date":"2026-03-24T22:14:04+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-24T02:05:38+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"225346697652868162107254664980135435819","date":"2026-03-24T01:08:11+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-24T00:51:37+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-10T03:56:24+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-10T03:55:53+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Orthopaedic Surgery and Research","date":"2026-03-07T14:39:40+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-orthopaedic-surgery-and-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"josr","sideBox":"Learn more about [Journal of Orthopaedic Surgery and Research](http://josr-online.biomedcentral.com)","snPcode":"13018","submissionUrl":"https://submission.nature.com/new-submission/13018/3","title":"Journal of Orthopaedic Surgery and Research","twitterHandle":"@MSKmedBMC","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"13aa0c12-6298-4c5f-8195-bb2be33d3b25","owner":[],"postedDate":"March 25th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-19T06:23:35+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-25 17:19:53","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9059249","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9059249","identity":"rs-9059249","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}