Discriminative Performance of the C-Reactive Protein–Triglyceride–Glucose Index for Endometriosis: A Case–Control Study

Endometriosis, a common gynecologic disorder, causes pain and fertility problems. Since laparoscopy, as a definitive diagnostic procedure, is considered invasive, finding reliable and noninvasive biomarkers is a clinical priority. This study evaluated the diagnostic performance of C-reactive protein–triglyceride–glucose index (CTI) for endometriosis.

In this case–control study, 153 participants with surgically confirmed endometriosis and 112 participants without visible endometriosis at laparoscopy were included. Fasting glucose, triglycerides (TG), total cholesterol, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were measured, and CTI was calculated using a previously described formula. Receiver operating characteristic (ROC) analysis was carried out to assess diagnostic discrimination and identify an exploratory threshold for CTI cutoff. Multivariable logistic regression was used to assess the independent relationship between CTI and endometriosis. Nested models were also assessed to examine the incremental contribution of TG and glucose beyond CRP.

Women with endometriosis exhibited higher levels of TG, total cholesterol, ESR, CRP, and CTI than controls (all P< 0.001), whereas fasting glucose did not differ significantly between groups. CTI showed good discrimination for endometriosis, with an area under the ROC curve (AUC) of 0.900 (95% CI, 0.858– 0.942). An exploratory cutoff of 9.686 yielded a sensitivity of 92.16% and specificity of 83.93%. CTI was independently associated with endometriosis after adjustment for age, body mass index, systolic and diastolic blood pressure (adjusted OR per 0.5-unit increase, 2.598; 95% CI, 2.079– 3.245; P< 0.001). However, CTI’s discriminatory performance was not significantly different from CRP’s. (AUC 0.898; P=0.827). Addition of TG to a CRP-based model significantly improved model fit (P=0.007), whereas addition of glucose did not (P=0.095); the overall difference in AUCs across the nested models was not statistically significant (P=0.719).

CTI showed good discrimination for endometriosis but did not significantly outperform CRP. It may serve as a complementary biomarker alongside clinical and imaging assessment. The infographic presents a study on endometriosis, highlighting CTI and CRP′s similar diagnostic performance. Sections include: Background - Endometriosis is linked to metabolic dysregulation. Methods - Case-control study with 153 endometriosis patients and 112 controls. Study Population - Groups compared for age and BMI; higher levels of TG, cholesterol, ESR, CRP and CTI in endometriosis (p less than 0.001). Diagnostic Performance - ROC analysis shows AUCs: CTI 0.900, CRP 0.898, ESR 0.846, TG 0.828. Key Finding - CTI and CRP have similar discriminative performance (DeLong p equal 0.8265). Conclusion - CTI shows high performance, similar to CRP, needing further validation. Visuals include uterus icons for groups, ROC curve plot and pathway icons showing inflammation, lipid dysregulation and glucose metabolism feeding into CTI. The layout follows a top-to-bottom reading order, structured by major sections.Graphical abstract summarizing the study population, methods, and diagnostic findings of a case–control study evaluating CTI in endometriosis. CTI showed good discriminatory performance, with no statistically significant difference in AUC compared with CRP.

endometriosis, C-reactive protein, triglycerides, erythrocyte sedimentation rate, C-reactive protein–triglyceride–glucose index Graphical Abstract:

Endometriosis is extrauterine endometrial-like tissue. It is accompanied by dysmenorrhea, pelvic pain, and fertility problems.1 Although the condition is highly common among women of reproductive age, diagnosis remains challenging. Laparoscopic visualization is considered the standard method of diagnosis, which frequently results in a delay between symptom presentation and confirmed diagnosis.2 Such diagnostic delays may contribute to endometriosis advancement, reduced quality of life, and higher healthcare demands. Growing evidence suggests that endometriosis should be regarded as a gynecologic disease with systemic inflammatory and metabolic associations. Saliva has also been investigated as a potential non-invasive biological source for endometriosis biomarkers; however, compared with blood and other biological compartments, the available evidence remains limited and requires further validation.3 In addition to local inflammatory processes, metabolic and immunological disturbances may contribute to the pathophysiology and progression of endometriosis. Lipid metabolic dysregulation, oxidative stress, and chronic inflammation have been associated with the pathophysiology of endometriosis and its potential long-term consequences.4,5 Recent molecular and bioinformatics studies have demonstrated that altered expression of lipid metabolism-associated genes may affect immune cell recruitment and inflammatory signaling within endometriotic lesions.6 In parallel, epidemiological data and meta-analyses showed a greater risk of endometriosis in women with unfavorable lipid profiles, including elevated total cholesterol levels.7 Alterations in glucose metabolism have also been described in endometriosis. Experimental studies suggest reduced insulin sensitivity and increased reliance on glycolytic pathways in endometriotic cells, leading to increased lactate production and enhanced inflammatory signaling.8 These metabolic changes may promote lesion survival, angiogenesis, and chronic inflammation. Inflammation represents a key feature of endometriosis. Elevated inflammation markers, including CRP, have been consistently reported in affected women.9 Persistent low-grade inflammation is a proposed risk factor for endometriosis and cardiovascular disease, indicating shared metabolic and inflammatory pathways.10 The C-reactive protein–triglyceride–glucose index (CTI) is a recently introduced composite inflammatory–metabolic index that consolidates inflammatory and metabolic markers obtained from commonly performed laboratory tests. CTI is considered a prognostic factor to predict insulin resistance and cardiovascular outcomes in previous studies.11 Due to the chronic inflammatory and metabolic characteristics of endometriosis, evaluation of CTI provides a practical and noninvasive approach for identifying affected women. Accordingly, this investigation proposed to evaluate the association between CTI and endometriosis and to compare inflammatory and metabolic parameters between women with and without the disease.

We conducted a case–control study between April 2024 and March 2025 at Rasoul-e-Akram Hospital, affiliated with Iran University of Medical Sciences, Tehran, Iran. Ethical approval was obtained from the Institutional Review Board of Iran University of Medical Sciences (IR.IUMS.REC.1402.1091), and all patients signed written informed consent; The study adhered to the ethical standards of the Declaration of Helsinki. Women aged 18–40 years with BMI < 30 kg/m2 and regular menstrual cycles were eligible. Participants were excluded if they had used hormonal contraceptives, gonadotropin-releasing hormone (GnRH) analogs, implants, hormonal intrauterine devices within the previous six months, or nicotine, hookah, or alcohol. Additional exclusion criteria were polycystic ovary syndrome (PCOS), hypertension, diabetes mellitus, autoimmune disease, family history of dyslipidemia, or incomplete clinical and laboratory records. A total of 265 women were recruited: 153 patients with confirmed endometriosis by visual intraoperative findings using ASRM criteria via laparoscopy comprised the case group, and 112 women without endometriosis as controls. Control participants underwent laparoscopic procedures for benign indications and/or infertility evaluation, and the absence of visible endometriosis was assessed intraoperatively. The study groups were comparable for age and body mass. Control participants underwent laparoscopic surgery for benign ovarian cystectomy or diagnostic laparoscopy as part of an infertility evaluation. The absence of endometriosis was confirmed through direct intraoperative visualization (Figure 1). | Figure 1 Flowchart of participant selection. Prepared with the assistance of OpenAI ChatGPT (GPT-5.6). | Sample Recruitment and Laboratory Measurements Blood samples (5 mL) were obtained at mid-cycle in the morning within the day before surgery after a 12-hour overnight fast. Serum CRP, glucose, triglycerides, and total cholesterol were measured using routine automated biochemical methods in the clinical laboratory. Commercially available reagents (Pars Azmoon Co., Tehran, Iran) were used according to the manufacturers’ instructions. CRP was measured using a quantitative standard CRP assay. Glucose was determined using the glucose oxidase–peroxidase (GOD-POD) method, triglycerides using the glycerol phosphate oxidase–peroxidase (GPO-PAP) method, and total cholesterol using the cholesterol oxidase–peroxidase (CHOD-PAP) method. All biochemical measurements were performed using a calibrated automated analyzer. Calibration and internal quality-control procedures were performed routinely according to the laboratory and manufacturers’ recommendations. The same laboratory procedures were applied consistently throughout the study period. CTI was calculated using the formula 0.412 × ln(C-reactive protein [mg/L]) + ln(Triglycerides [mg/dL] × Fasting Glucose [mg/dL]/2), according to the previously described methodology, using the established composite formula integrating C-reactive protein, triglycerides, and fasting glucose. The present study did not modify the original formula or develop a new CTI model, rather, it evaluated the diagnostic performance of the previously described index in women with endometriosis. The mid-cycle period was defined as menstrual cycle days 12–16 based on participants’ self-reported cycle dates. Bowel preparation with polyethylene glycol (PEG) was performed on the day before surgery, while prophylactic cefazolin was administered at anesthesia induction on the day of surgery. Clinical and Demographic Data Demographic and clinical features, including age, weight, height, were recorded. Systolic and diastolic blood pressures and waist circumference were assessed using standardized procedures. Statistical Analysis Sample Size Calculation The required sample size was estimated based on the desired precision of the area under the receiver operating characteristic curve (AUC). Assuming an expected AUC of 0.90, a two-sided 95% confidence interval with a total width of 0.09, and a negative-to-positive ratio of 1.5, the minimum required sample size was 230 participants (92 positive and 138 negative subjects). The final analysis included 265 participants. Variables were assessed for normality using the Kolmogorov–Smirnov test. Continuous variables are presented as mean ± standard deviation (SD) or median (interquartile range), as appropriate. The statistical analysis was expanded to describe the diagnostic ROC analysis, logistic regression, ROC comparison, bootstrap analysis of the cutoff, assessment of linearity in the logit, multicollinearity, and model calibration. The optimal CTI cutoff was selected by maximizing the Youden index (sensitivity + specificity − 1). Because the cutoff was derived from the same study population in which its diagnostic performance was evaluated, it was considered an internally derived exploratory threshold rather than a clinically validated cutoff. To assess the stability of the estimated cutoff, bootstrap resampling was performed. The linearity-in-the-logit assumption for CTI was assessed using the Box–Tidwell approach. Multicollinearity among predictors was assessed using variance inflation factors (VIFs).

There were no significant differences in age or BMI between the study groups. The mean age was 30.69 ± 4.48 years in the endometriosis group and 31.54 ± 4.06 years in the control group, while the mean BMI was 22.26 ± 2.49 and 22.55 ± 3.05 kg/m2, respectively. The number of pregnancies also did not differ significantly between the groups. An overview of the participants’ demographic and clinical characteristics is provided in Table 1. | Table 1 Demographic and Clinical Characteristics of Women in the Endometriosis and Control Groups | Lipid and glucose profile analysis revealed significantly higher triglyceride and total cholesterol levels in the endometriosis patients in comparison with the control group (p < 0.001 for all comparisons). Fasting glucose levels were similar between the groups. Inflammatory markers were significantly elevated in the endometriosis group. Mean ESR (mm/h), CRP (mg/L), and CTI were all significantly higher in women with endometriosis than in controls (p < 0.001 for all comparisons) (Table 2). | Table 2 Laboratory Findings in the Endometriosis and Control Groups | Multivariable binary logistic regression analysis was performed to assess the adjusted association between CTI and endometriosis. The association between CTI and endometriosis remained statistically significant after adjustment for covariates. The adjusted OR was 2.598 (95% CI: 2.079–3.245; p < 0.001) for each 0.5-unit increase in CTI. For comparison, the corresponding adjusted ORs were 6.748 (95% CI: 4.324–10.530; p < 0.001) per 1-unit increase and 11.556 (95% CI: 6.533–20.442; p < 0.001) per 1-SD increase. Given the relatively narrow distribution of CTI values, the 0.5-unit increment was used as the primary scale for reporting the association, while the 1-SD estimate was considered a sensitivity analysis (Table 3). | Table 3 Multivariable Logistic Regression Analysis of the Association Between CTI, Clinical Variables, and Endometriosis | An independent association was also observed between systolic blood pressure and endometriosis. (adjusted OR: 1.094, 95% CI: 1.032–1.160; p = 0.002), whereas age, BMI, and diastolic blood pressure were not statistically significant. The linearity-in-the-logit assumption for CTI was assessed using the Box–Tidwell approach. The interaction between CTI and its natural logarithm was not statistically significant (p = 0.227), providing no evidence of departure from linearity. Variance inflation factors ranged from 1.01 to 1.29, indicating no evidence of problematic multicollinearity among the predictors (Table 3). Model calibration was assessed using the Hosmer–Lemeshow goodness-of-fit test with 10 groups. The test showed no statistically significant evidence of lack of fit within the study sample (χ2(8) = 13.48, p = 0.096). Given the case–control design and the artificially determined case/control proportion, this finding should not be interpreted as evidence of population-level calibration of absolute risk. Receiver operating characteristic (ROC) curve analysis showed good discriminative performance of CTI in distinguishing women with endometriosis from controls (AUC = 0.900, 95% CI: 0.854–0.941). The optimal CTI cutoff identified by maximizing the Youden index was 9.686. Because this threshold was derived from the same cohort used for diagnostic evaluation, its performance was considered exploratory. In bootstrap analysis, the estimated cutoff showed a standard error of 0.096, with a 95% bootstrap confidence interval of 9.498–9.874, suggesting relative stability of the estimated threshold within the study sample. At the exploratory cutoff of 9.686, CTI showed a sensitivity of 92.16% (95% CI: 86.70–95.88%) and a specificity of 83.93% (95% CI: 75.79–90.19%). The corresponding positive and negative likelihood ratios were 5.73 (95% CI: 3.75–8.78) and 0.093 (95% CI: 0.054–0.162), respectively. CTI demonstrated an AUC of 0.900 (95% CI: 0.858–0.942). CRP showed comparable discriminative performance, with an AUC of 0.898 (95% CI: 0.856–0.941). ESR and triglycerides showed lower AUCs of 0.846 (95% CI: 0.798–0.895) and 0.828 (95% CI: 0.777–0.879), respectively. Formal comparison of the correlated ROC curves showed no significant difference between CTI and CRP (p = 0.827), whereas the AUC of CTI was significantly higher than those of ESR (p = 0.003) and triglycerides (p < 0.001) (Table 4 and Table 5; Figures 2 and 3). | Figure 2 Receiver operating characteristic (ROC) curve plot for CRP, CTI, TG, and ESR. | | Figure 3 Receiver operating characteristic curves comparing the diagnostic performance of CTI, CRP, ESR, and triglycerides. | | Table 4 Diagnostic Performance of CTI, CRP, ESR, and Triglycerides for Discriminating Patients with Endometriosis from Controls | | Table 5 Pairwise Comparison of the Diagnostic Performance of CTI and Other Biomarkers | To further assess the incremental contribution of the CTI components, nested logistic regression models were compared. The CRP-only model had an AUC of 0.898 (95% CI, 0.856–0.941), while adding triglycerides increased the AUC to 0.900 (95% CI, 0.858–0.942) and significantly improved model fit (likelihood-ratio χ2=7.28, P=0.007). Further addition of glucose increased the AUC to 0.904 (95% CI, 0.862–0.945), but this improvement in model fit was not statistically significant (likelihood-ratio χ2=2.79, P=0.095). The overall comparison of AUCs across the three nested models was not statistically significant (P=0.719), indicating that the incremental discrimination provided by adding triglycerides and glucose to CRP was limited (Table 6). | Table 6 Incremental Contribution of Triglycerides and Fasting Glucose to the Diagnostic Performance of CRP |

In the current case–control investigation, women with endometriosis demonstrated significantly higher inflammatory and metabolic parameters compared with controls, including elevated triglyceride, total cholesterol, ESR, CRP, and CTI values. Importantly, CTI showed strong discriminative performance for endometriosis, with high sensitivity and specificity and an AUC approaching 0.90. The multivariable model incorporated systolic blood pressure as a covariate, and its adjusted association with endometriosis was statistically significant. These findings are consistent with the multifactorial nature of endometriosis and the involvement of inflammatory processes associated with pelvic disease. Chronic inflammation, dyslipidemia, and altered glucose metabolism have been implicated in endometriosis and have also been discussed in relation to cardiovascular health.12–16 In the present study, the higher ESR and CRP levels observed in participants with endometriosis support the presence of systemic inflammatory features. However, cardiovascular outcomes were not directly evaluated, and the present case–control design does not permit causal inference. Consistent with previous literature, triglyceride and total cholesterol levels were higher in women with endometriosis. Saei Ghare Naz et al similarly found an increased prevalence of metabolic syndrome, greater waist circumference, and lower high-density lipoprotein levels among women with endometriosis, findings that may predispose affected individuals to metabolic and cardiovascular complications.17 Moreover, Zhe et al reported a statistically significant association between the lipid accumulation product and endometriosis, reporting a 1.5-fold increase in disease risk with lipid elevation, particularly in women over 35 years of age or those with higher HbA1c levels.18 Differences between studies may reflect variation in study design, sample characteristics, and concurrent metabolic conditions. Our analysis showed that fasting glucose was marginally higher in women with endometriosis. Despite the observed variation, no statistically significant difference was identified. Previous evidence investigating the relationship between endometriosis and impaired glucose metabolism or type 2 diabetes has yielded inconsistent results.12,19,20 Farland et al reported no overall increase in type 2 diabetes risk among endometriosis patients but noted a moderately elevated risk in specific subgroups, including non-obese women and those without infertility or gestational diabetes.21 Emerging evidence also suggests that effective treatment of endometriosis may positively influence metabolic health. Improvements in lipid parameters following surgical excision of deep infiltrating endometriotic lesions have been reported, supporting a link between disease activity and metabolic dysregulation.22 In addition, Chen et al demonstrated associations between endometriosis and multiple systemic metabolic indices, such as BMI, glucose regulation, and lipid metabolism, highlighting the importance of metabolic optimization for improving fertility outcomes.23 However, the nested-model analysis provided a more cautious interpretation of the incremental value of individual variables comprising CTI beyond CRP alone. Adding triglycerides to CRP significantly improved model fit and reduced the information criteria, whereas the subsequent addition of glucose did not significantly improve model fit. Despite a small numerical increase in AUC across the models, the differences in discrimination were not statistically significant. These findings demonstrate the high discrimination observed with CTI may largely reflect the contribution of CRP, while triglycerides may provide additional statistical information without translating into a significant improvement in overall discrimination. Therefore, the relatively high diagnostic performance of CTI does not demonstrate that CTI offers a substantial diagnostic advantage over CRP alone. Because of the case-control design and the artificially determined proportion of cases and controls, calibration of absolute predicted probabilities should not be considered as population-level risk calibration. The model results should therefore be interpreted primarily in terms of discrimination within the study sample rather than as estimates of absolute disease probability in clinical populations. Larger prospective studies are warranted to determine whether the integrated inflammatory-metabolic index offers clinically meaningful incremental value. Importantly, after controlling for confounding variables, age, BMI, and blood pressure measurements, the relationship between CTI and endometriosis was significant. The adjusted odds ratio indicated that each 0.5-unit increase in CTI was associated with approximately a 2.6-fold increase in the odds of endometriosis; the corresponding OR for a 1-unit increase was 6.75. Because of the case–control design, the observed association cannot establish causality or temporal relationships. Therefore, the findings should be interpreted as an association between CTI and endometriosis rather than as evidence of a causal relationship. Although CTI had the numerically highest AUC, no statistically significant difference in discriminatory performance was observed between CTI and CRP. Indicating that its incremental diagnostic value remains uncertain. CTI should be considered as a complementary biomarker within the established diagnostic pathway for endometriosis, rather than as a replacement for clinical assessment or appropriate imaging, particularly transvaginal ultrasonography and, when indicated, magnetic resonance imaging for assessment of deep disease. Established serum biomarkers such as CA-125 have also been investigated in endometriosis, but their diagnostic utility is limited by imperfect sensitivity and specificity. Given its comparable diagnostic discrimination to CRP in the present study, whether CTI provides additional value beyond established biomarkers or imaging remains uncertain and requires prospective validation. At the exploratory cutoff of 9.686, CTI showed a positive likelihood ratio (LR+) of 5.73 and a negative likelihood ratio (LR−) of 0.093. These likelihood ratios offer additional information on the discriminatory performance of CTI within the study population. However, because the cutoff and diagnostic performance were derived from the same case–control cohort, these estimates should be interpreted as exploratory and need validation in independent, prospective clinical populations before clinical application. The adjusted analysis also showed an association between systolic blood pressure and endometriosis. This finding should be interpreted cautiously, as the case–control design does not establish causality and the study was not designed to investigate cardiovascular determinants of endometriosis. Further studies are needed to determine whether this association is reproducible in clinically representative populations. Strengths and Limitations One of the strengths of our study is that it is among the relatively few investigations specifically evaluating the diagnostic utility of the C-reactive protein–triglyceride–glucose index (CTI) in women with endometriosis. CTI is a simple, inexpensive, and readily accessible composite biomarker that may have potential as an adjunctive noninvasive marker for endometriosis. In addition, the study provides a direct comparison of CTI with individual biomarkers, including CRP, ESR, and triglycerides, and further evaluates the incremental contribution of its metabolic components. Some limitations should be considered when interpreting the results. First, the single-center case–control design and the selected study population may have introduced selection bias and limit the generalizability of the findings to other populations and clinical settings. Second, all patients with endometriosis included in the present study had stage III or IV disease. Although the overall disease spectrum represented in the study can therefore be described, disease stage was not separately coded in the final analytic dataset, precluding reliable stage-specific comparisons between stage III and stage IV disease. Moreover, the study does not represent the full clinical spectrum of endometriosis, particularly stage I, stage II, or isolated superficial disease. Third, the indication for surgery among control participants was not retained in the final analytic dataset; therefore, diagnosis-specific subgroup analyses and detailed characterization of the control pathology could not be performed. Unmeasured confounding factors may influence the results, because information on several potentially relevant factors, including dietary habits, physical activity, socioeconomic status, detailed medication history, and unrecognized metabolic conditions, was not systematically available or retained in the final analytic dataset. Similarly, information on symptom phenotype, occupation, fertility status, and income was unavailable for analysis. In addition, formal prospective blinding of investigators to disease status and biomarker results was not documented for all study components, and observer-related bias therefore cannot be completely excluded. The exclusion of women with diabetes and hypertension, together with the BMI restriction, may further limit external validity. Consequently, the diagnostic performance of CTI in women with obesity, diabetes, hypertension, or other major metabolic comorbidities remains uncertain. The relatively homogeneous population resulting from these restrictive eligibility criteria may also have influenced the observed discriminatory performance of CTI. Thus, the reported AUC should be considered within the context of the selected study population rather than as an estimate applicable to all women with endometriosis. Finally, external validation of the CTI cutoff was not performed, and the study was not designed to evaluate longitudinal or prognostic outcomes. Although CTI demonstrated good discriminatory performance, its diagnostic utility should be interpreted in conjunction with the finding that its performance was not significantly different from that of CRP alone. Therefore, CTI should not be considered a replacement for established clinical assessment, imaging, or other laboratory markers. Future prospective, multicenter studies including larger and more heterogeneous populations, broader disease stages, and women with common metabolic comorbidities are required to externally validate the observed diagnostic performance and determine the potential clinical utility of CTI. Because of the case–control design, causal or temporal relationships between CTI components and endometriosis cannot be established. The observed associations may reflect shared confounding factors, reverse causation, or other unmeasured influences that cannot be distinguished within the present design. Furthermore, the clinical setting and surgical recruitment may limit the applicability of the findings to untreated or community-based populations. Accordingly, the association between CTI and endometriosis should be considered as a diagnostic discrimination and does not establish causality.

Women with endometriosis showed higher inflammatory and metabolic biomarker levels than controls. CTI demonstrated high discriminatory performance in this selected case–control population; however, its discrimination was not significantly different from that of CRP alone. Because the cutoff was derived within the same dataset and the study population consisted of surgically evaluated women with stage III–IV endometriosis, the findings should be regarded as exploratory rather than as evidence of diagnostic validity. External validation in prospective, clinically representative populations is required to determine the reproducibility and clinical utility of CTI for endometriosis. Artificial Intelligence (AI) Statement The Graphical Abstract and Figure 1 (participant flowchart) were prepared with the assistance of OpenAI ChatGPT (GPT-5.6) for graphic design and visual presentation. The authors reviewed the terms of use of the AI tool and confirm its suitability for publication. The authors also confirm that they have the right to publish the generated images and that any required permissions have been obtained. AI tools were not used for data generation, statistical analysis, or interpretation of the study results. Abbreviations CTI, C-reactive protein–triglyceride–glucose index; BMI, body mass index; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; ROC, Receiver operating characteristic; AUC, area under the curve; GnRH, gonadotropin-releasing hormone; PCOS, polycystic ovary syndrome; TG, triglycerides; SD, standard deviation. Data Sharing Statement The datasets analyzed during the current study are available from the corresponding authors upon reasonable request. Ethics Approval and Informed Consent The study was approved by the Ethics Committee of Iran University of Medical Sciences (IR.IUMS.REC.1402.1091). Written informed consent was obtained from all participants prior to enrollment. The study was conducted in accordance with the Declaration of Helsinki. Author Contributions All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Disclosure The authors report no conflicts of interest in this work.

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The full terms of this license are available at https://www.dovepress.com/terms and incorporate the Creative Commons Attribution - Non Commercial (unported, 4.0) License. By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms. Recommended articles The Impact of Preoperative Inflammatory Activity in Patients with Ankylosing Spondylitis on Postoperative Joint Function: A Retrospective Cohort Study Man SL, Ji XJ, Ding YY, Li HC, Guo SY, Bian T, Zhang L Journal of Inflammation Research 2026, 19:576376 Published Date: 4 February 2026