Association Between Blood Urea Nitrogen to Serum Albumin Ratio and 28-Day Mortality Risk in Sepsis Patients with AKI Undergoing Continuous Renal Replacement Therapy: A Secondary Analysis Based on a Retrospective Cohort Study

Association Between Blood Urea Nitrogen to Serum Albumin Ratio and 28-Day Mortality Risk in Sepsis Patients with AKI Undergoing Continuous Renal Replacement Therapy: A Secondary Analysis Based on a Retrospective Cohort Study | 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 Association Between Blood Urea Nitrogen to Serum Albumin Ratio and 28-Day Mortality Risk in Sepsis Patients with AKI Undergoing Continuous Renal Replacement Therapy: A Secondary Analysis Based on a Retrospective Cohort Study Bufei Xie, Xiaoxiao Qu, Huibo Wang, Guosong Jiang, Zimiao Zhu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6589198/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background : The blood urea nitrogen to albumin ratio (BAR) reflects both metabolic stress and nutritional status and may serve as a valuable prognostic marker in critically ill patients. However, its association with 28-day mortality in sepsis-related acute kidney injury (AKI) remains unclear, particularly among those receiving continuous renal replacement therapy (CRRT). This study aims to evaluate the relationship between BAR and short-term mortality and to explore its clinical relevance in risk stratification for critically ill patients. Methods :This study was a secondary analysis based on a publicly available dataset. A total of 790 critically ill patients with sepsis-associated acute kidney injury who received continuous renal replacement therapy (CRRT) between January 2009 and September 2016 were included. The dataset was obtained from the Dryad repository. The blood urea nitrogen to albumin ratio (BAR) was calculated at the initiation of CRRT, and patients were categorized into tertiles based on BAR values. Cox proportional hazards regression models, restricted cubic spline analysis, and Kaplan–Meier survival curves were used to evaluate the association between BAR and 28-day mortality. To assess the robustness of the findings, subgroup analyses were conducted. Results : Among 790 patients, 494 (62.5%) died within 28 days. Higher blood urea nitrogen to albumin ratio (BAR) was significantly associated with increased 28-day mortality. Patients in the highest tertile (Q3) had a 2.54-fold increased risk compared to those in the lowest tertile (Q1) (HR = 2.54, 95% CI: 1.62–3.98, P < 0.001). Restricted cubic spline analysis revealed a linear dose-response relationship. Kaplan-Meier curves showed significantly lower survival in the Q3 group ( P < 0.001). Subgroup analyses confirmed the robustness of the associations. Conclusions : The blood urea nitrogen to albumin ratio (BAR) is an independent and clinically relevant predictor of 28-day mortality in septic patients with AKI undergoing CRRT. Elevated BAR is associated with significantly increased short-term mortality risk. Monitoring BAR may aid in early risk stratification and inform individualized treatment strategies in critically ill populations. Blood urea nitrogen to albumin ratio (BAR) Sepsis Acute kidney injury (AKI) Continuous renal replacement therapy (CRRT) 28-day mortality Figures Figure 1 Figure 2 Figure 3 Introduction Sepsis-associated acute kidney injury (AKI) is a common and life-threatening complication in critically ill patients, particularly those admitted to intensive care units (ICU)[1, 2]. This condition represents a severe intersection of systemic inflammation, organ dysfunction, and metabolic derangement, with high rates of morbidity and mortality[3, 4]. For patients requiring continuous renal replacement therapy (CRRT), the prognosis is particularly poor[5, 6]. Despite improvements in supportive care, early risk stratification remains challenging due to the lack of simple, reliable, and dynamic prognostic biomarkers. The blood urea nitrogen to albumin ratio (BAR) has recently gained attention as a composite marker reflecting both catabolic stress and nutritional status—two critical determinants of outcome in critically ill populations[7, 8]. However, limited data exist regarding its prognostic value in patients with sepsis-associated AKI, especially those undergoing CRRT. Such patients face a particularly high risk of poor outcomes, given the interplay between sepsis-related inflammation, impaired renal function, and the challenges of continuous renal support. To address this gap, the present study aimed to investigate the association between BAR and 28-day all-cause mortality in patients with sepsis-associated AKI receiving CRRT. We hypothesized that higher BAR levels are independently associated with increased short-term mortality and that BAR may serve as a practical, accessible biomarker for early risk assessment in this high-risk population. Methods Study Design and Data Source This study was a secondary analysis of a publicly available, de-identified dataset originally provided by Seung Hyeok Han from the Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, Korea. The dataset was obtained from the Dryad Digital Repository (https://doi.org/10.5061/dryad.6v0j9) and includes patients admitted to the intensive care units (ICU) of Yonsei University Health System Severance Hospital and the National Health Insurance Service Medical Centre Ilsan Hospital between January 2009 and September 2016[9]. All patients received continuous renal replacement therapy (CRRT). Study Population Inclusion criteria for the original cohort were: (1) diagnosis of sepsis according to the Sepsis-3 definition (suspected infection and SOFA score ≥2)[10]; (2) acute kidney injury stage 2 based on the Acute Kidney Injury Network (AKIN) criteria[11]; (3) treatment with CRRT. Exclusion criteria included: age <18 years, pre-existing chronic kidney disease, prior dialysis or CRRT, pregnancy, postrenal obstruction, and history of kidney transplantation. The final analysis included 790 patients with sepsis-associated AKI who received CRRT(Fig 1). CRRT protocol Nephrologists decided whether or not to initiate CRRT upon the development of sepsis with AKI in ICU patients. The indications for CRRT use included uncontrolled volume overload, intractable hyperkalaemia or metabolic acidosis. The type of CRRT used was continuous venovenous haemodiafiltration through the internal jugular, subclavian or femoral veins. CRRT was started at a blood flow rate of 100 ml/min and was increased up to 150 ml/min. The total effluent volume as a sum of the dialysis and replacement doses was targeted to deliver ≥35 ml/kg per h in all patients using a multiFiltrate machine (Fresenius Medical Care, Bad Homburg, Germany) or a PRISMAFLEX System (Baxter International, Lund, Sweden). Data Collection Clinical data including baseline demographics, comorbidities, laboratory test results (such as BUN, serum albumin, creatinine, and C-reactive protein), vital signs (blood pressure, heart rate), and clinical scores (APACHE II and SOFA) were collected. Patients were stratified into three groups based on the BUN/Alb ratio: Q1 (1.80–3.96), Q2 (3.96–4.72), and Q3 (4.72–7.07). Outcome The primary outcome was 28-day all-cause mortality following CRRT initiation. Statistical Analysis Patients were categorized into tertiles based on their blood urea nitrogen to albumin ratio (BAR) at the initiation of continuous renal replacement therapy (CRRT). Continuous variables were expressed as mean (standard deviation, SD) or median (interquartile range, IQR) according to their distribution, while categorical variables were reported as counts and percentages (n, %). Differences across BAR tertiles were assessed using one-way analysis of variance (ANOVA) or the Kruskal–Wallis test for continuous variables, and the chi-square test for categorical variables. Multivariable Cox proportional hazards regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between BAR and 28-day all-cause mortality. Three models were constructed: Model 1 was unadjusted; Model 2 was adjusted for age and sex; and Model 3 was further adjusted for hypertension, creatinine, phosphate, C-reactive protein (CRP), Charlson comorbidity index (CCI), and SOFA score. Restricted cubic spline models were applied to examine potential nonlinear dose-response relationships between BAR and mortality risk. Kaplan–Meier survival curves were constructed to compare cumulative 28-day mortality across BAR tertiles, with significance assessed using the log-rank test. Subgroup analyses and interaction tests were performed using multivariable Cox models to evaluate potential effect modification. All statistical analyses were performed using R software (version 4.2.2) and the Free Statistics analysis platform (version 2.1, Beijing, China). A two-sided P value < 0.05 was considered statistically significant. Results Baseline characteristics This study included 790 critically ill patients with sepsis-associated acute kidney injury (AKI) undergoing CRRT. The mean age was 63.6 ± 14.1 years, and 490 patients (62.0%) were male. The mean APACHE II score was 23.3 ± 7.5, and the mean SOFA score was 8.6 ± 3.6. Table 1 presents the baseline characteristics of patients stratified by BAR tertiles. Patients in the highest tertile (Q3) had significantly higher APACHE II scores (P < 0.001), SOFA scores (P < 0.001), and blood urea nitrogen levels (P < 0.001), as well as lower serum albumin concentrations (P < 0.001), compared to those in the lowest tertile (Q1). Univariate Analysis of Factors Associated with 28-Day Mortality Supplementary Table 1 presents the results of univariate Cox proportional hazards regression analyses for 28-day all-cause mortality. Several clinical variables were significantly associated with increased mortality risk, including blood urea nitrogen to albumin ratio (BAR) (HR = 1.0092, 95% CI: 1.0037–1.0147, P < 0.001), phosphate (HR = 1.32, 95% CI: 1.13–1.54, P < 0.001), and SOFA score (HR = 1.11, 95% CI: 1.06–1.16, P < 0.001).In contrast, higher levels of albumin (HR = 0.41, 95% CI: 0.28–0.59, P < 0.001) and hemoglobin (HR = 0.95, 95% CI: 0.93–0.98, P < 0.001) were associated with a lower risk of death. Variables such as age, sex, white blood cell count, and comorbidities including hypertension and diabetes were not significantly associated with 28-day mortality (P > 0.05). Association Between BAR and 28-Day Mortality Multivariable Cox regression analysis showed a significant association between BAR and 28-day all-cause mortality ( Table 2 ). In the fully adjusted model, patients in the highest BAR tertile (Q3) had a 2.54-fold increased risk of death compared to those in the lowest tertile (Q1) (HR = 2.54, 95% CI: 1.62–3.98, P < 0.001). When treated as a continuous variable (log2-transformed), each doubling of BAR was associated with a 60% increased risk of 28-day mortality (HR = 1.60, 95% CI: 1.28–2.00, P < 0.001). Restricted Cubic Spline Analysis Restricted cubic spline modeling revealed a linear dose–response relationship between BAR and 28-day mortality ( Supplementary Figure 1 ). The overall association was statistically significant (P < 0.001), with no evidence of non-linearity (P for non-linearity = 0.284). Kaplan–Meier Survival Analysis Kaplan–Meier survival curves indicated that patients in the highest BAR tertile had the lowest cumulative survival over 28 days ( Figure 2 ; P < 0.001). Survival probability declined progressively with increasing BAR tertiles. Subgroup Analysis Subgroup analyses demonstrated that the association between BAR and 28-day mortality was consistent across predefined strata, including age, sex, SOFA score, creatinine level, and CRP level ( Figure 3 ). No significant interactions were detected (P for interaction > 0.05). Discussion First, this study demonstrates that the blood urea nitrogen to albumin ratio (BAR), a readily available clinical biomarker, is independently associated with 28-day mortality in patients with sepsis-associated acute kidney injury (AKI) undergoing continuous renal replacement therapy (CRRT). We found a consistent linear dose-response relationship between increasing BAR values and higher short-term mortality risk, supported by multivariable Cox regression and restricted cubic spline analyses. Second, the prognostic value of BAR remained robust across multiple clinical subgroups without significant interaction effects, suggesting its broad applicability in critically ill populations. Third, BAR reflects both catabolic stress and nutritional reserve—two crucial prognostic domains in sepsis and AKI—thus offering pathophysiological relevance alongside practical utility. Finally, the simplicity, accessibility, and strong predictive ability of BAR make it a promising candidate for early risk stratification and potential decision-making support in CRRT settings. Compared to previous studies, our work addresses a significant gap in the literature. While BAR has been explored in general ICU populations, pneumonia, and cardiac failure, its prognostic utility in patients with sepsis-associated AKI receiving CRRT has not been well-established[ 12 – 14 ]. Previous evidence was either limited by small sample sizes, inconsistent outcomes, or lacked adjustment for key confounders such as C-reactive protein, phosphate, and SOFA score. For example, studies by Cai S et al. (2022)[ 15 ] and Wang Y et al. (2023)[ 16 ] found that elevated BAR was associated with mortality in non-AKI patients with sepsis, but did not address the influence of continuous renal support or validate findings in high-risk AKI subgroups. Our study improves upon prior work by focusing on a well-defined, high-risk cohort using a large, multicenter dataset and rigorous statistical adjustment, thus enhancing the generalizability and clinical relevance of our findings. Biologically, the association between elevated BAR and increased mortality in sepsis-associated AKI may be explained by multiple mechanisms. Blood urea nitrogen (BUN) levels reflect nitrogenous waste accumulation, which is exacerbated in renal dysfunction and systemic catabolism[ 17 , 18 ]. Hypoalbuminemia, on the other hand, indicates poor nutritional status, inflammation, and impaired liver function—each of which has been linked to adverse outcomes in critically ill patients[ 19 ]. A high BAR thus integrates both metabolic imbalance and diminished physiological reserve, which together may accelerate organ failure, compromise immune response, and worsen clinical trajectories in septic AKI[ 20 ]. The clinical advantages of our findings are notable. BAR can be rapidly calculated from two routine laboratory parameters, making it an easily implementable tool for early mortality risk assessment. In resource-limited settings or early triage scenarios, it could help prioritize patients for aggressive supportive care or closer monitoring. Additionally, as BAR incorporates both renal function and nutritional status, it may also aid in guiding individualized nutrition and fluid management strategies during CRRT. Nonetheless, this study has several limitations. First, its retrospective nature may introduce selection bias and unmeasured confounding. Second, dynamic changes in BAR during CRRT treatment were not captured; only baseline levels were analyzed. Third, residual confounding from unmeasured variables such as infection site, pathogen type, and use of vasopressors cannot be excluded. To mitigate these issues, we conducted rigorous multivariable adjustment and performed subgroup analyses to test robustness. Future prospective studies with repeated BAR measurements and expanded covariate sets are warranted to validate and extend these findings. Conclusion The BUN/Alb ratio is a significant predictor of 28-day mortality in septic patients with acute kidney injury (AKI) undergoing continuous renal replacement therapy (CRRT). For each one-unit increase in the BAR, the 28-day mortality risk increases significantly by 60%. This ratio provides valuable prognostic information and can help clinicians identify high-risk patients early, potentially guiding treatment decisions and improving patient outcomes. Declarations Data Availability The data used in this study are publicly available from the Dryad repository. The dataset can be accessed through the following link: https://datadryad.org/stash. The dataset is under the citation of Jung, Su-Young J et al. (2019), "Data from: Phosphate is a potential biomarker of disease severity and predicts adverse outcomes in acute kidney injury patients undergoing continuous renal replacement therapy," Dryad, Dataset, https://doi.org/10.5061/dryad.6v0j9. Authors contributions BFX contributed to study design, data collection, statistical analysis, and manuscript drafting. XXQ, HBW, and GSJ assisted with data cleaning and management. ZMZ supervised the project and critically revised the manuscript. All authors read and approved the final version of the manuscript Ethical approval and consent to participate The original study was approved by the Yonsei University Health System Severance Hospital Institutional Review Board (No. 4–2016-1073). For our sec‑ondary study based on a public database, ethical approval was not required. A waiver of informed consent was obtained because of the nature of the study. This study conformed to the guidelines of the Helsinki Declaration. Conflict of interest All the authors have declared no competing interest. Consent for publication Not applicable References Wang, D.H., et al., Attributable mortality of acute kidney injury among critically ill patients with sepsis: a multicenter, retrospective cohort study. BMC Nephrol, 2024. 25 (1): p. 125. Pais, T., S. Jorge, and J.A. Lopes, Acute Kidney Injury in Sepsis. Int J Mol Sci, 2024. 25 (11). Sun, J., et al., Systemic Immune-Inflammation Index (SII) as a Predictor of Short-Term Mortality Risk in Sepsis-Associated Acute Kidney Injury: A Retrospective Cohort Study. Med Sci Monit, 2024. 30 : p. e943414. Tang, J., et al., Systemic inflammation response index as a prognostic factor for patients with sepsis-associated acute kidney injury: a retrospective observational study. J Int Med Res, 2024. 52 (3): p. 3000605241235758. Li, Y., et al., [Construction of prognostic prediction model for patients with sepsis-induced acute kidney injury treated with continuous renal replacement therapy]. Zhonghua Wei Zhong Bing Ji Jiu Yi Xue, 2024. 36 (12): p. 1268-1272. Fukuda, M., et al., Association of Baseline Renal Function with Mortality in Patients with Sepsis Requiring Continuous Renal Replacement Therapy for Acute Kidney Injury: A Single-Center Retrospective Study. Blood Purif, 2023. 52 (2): p. 148-156. Huang, Y., et al., Association of the blood urea nitrogen to serum albumin ratio and all-cause mortality in critical ill acute ischemic stroke patients: a retrospective cohort study of MIMIC-IV database 3.0. Front Nutr, 2024. 11 : p. 1509284. Li, W., Q. Huang, and K. Zhan, Association of Serum Blood Urea Nitrogen to Albumin Ratio with in-Hospital Mortality in Patients with Acute Ischemic Stroke: A Retrospective Cohort Study of the eICU Database. Balkan Med J, 2024. 41 (6): p. 458-468. Jung, S.Y., et al., Phosphate is a potential biomarker of disease severity and predicts adverse outcomes in acute kidney injury patients undergoing continuous renal replacement therapy. PLoS One, 2018. 13 (2): p. e0191290. Shankar-Hari, M., et al., Developing a New Definition and Assessing New Clinical Criteria for Septic Shock: For the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). Jama, 2016. 315 (8): p. 775-87. Ronco, C., et al., Improving outcomes from acute kidney injury (AKI): Report on an initiative. Int J Artif Organs, 2007. 30 (5): p. 373-6. Zhang, S., et al., Blood urea nitrogen to serum albumin ratio as a new indicator of disease severity and prognosis in idiopathic pulmonary artery hypertension. Respir Med, 2024. 227 : p. 107643. Zhang, L., et al., Blood urea nitrogen to serum albumin ratio: a novel mortality indicator in intensive care unit patients with coronary heart disease. Sci Rep, 2024. 14 (1): p. 7466. Liu, S., et al., Blood urea nitrogen to serum albumin ratio as a new prognostic indicator in type 2 diabetes mellitus patients with chronic kidney disease. Sci Rep, 2024. 14 (1): p. 8002. Cai, S., et al., Association between blood urea nitrogen to serum albumin ratio and in-hospital mortality of patients with sepsis in intensive care: A retrospective analysis of the fourth-generation Medical Information Mart for Intensive Care database. Front Nutr, 2022. 9 : p. 967332. Wang, Y., et al., Prognostic impact of blood urea nitrogen to albumin ratio on patients with sepsis: a retrospective cohort study. Sci Rep, 2023. 13 (1): p. 10013. Hall, P.M., M. Schuman, and D.G. Vidt, Laboratory tests of renal function. CRC Crit Rev Clin Lab Sci, 1976. 7 (1): p. 33-47. Nogi, K., et al., Prognostic Value of Fractional Excretion of Urea Nitrogen at Discharge in Acute Decompensated Heart Failure. J Am Heart Assoc, 2021. 10 (16): p. e020480. Zheng, L.J., et al., Reduced serum albumin as a risk factor for poor prognosis in critically ill patients receiving renal replacement therapy. BMC Nephrol, 2021. 22 (1): p. 305. Bhatraju, P.K., M.M. Wurfel, and J. Himmelfarb, Trajectory of Kidney Function: The Canary in Sepsis. Am J Respir Crit Care Med, 2020. 202 (9): p. 1211-1212. Table Table 1 Baseline Characteristics of Study Population Variables Total T1( N= 263) T2( N= 263) T3( N= 264) P ( N= 790) 1.80-3.96 3.96-4.72 4.72-7.07 Demographics Age.Y 63.6 ± 14.1 61.5 ± 15.4 65.0 ± 12.8 64.4 ± 13.9 0.011 Male,n(%) 490 (62.0) 157 (59.7) 162 (61.6) 171 (64.8) 0.479 BMI (kg/m2) 23.6 ± 4.5 23.9 ± 4.1 23.6 ± 4.5 23.2 ± 4.7 0.192 Comorbidities MI, n (%) 72 ( 9.1) 29 (11) 22 (8.4) 21 (8) 0.413 CHF, n (%) 144 (18.2) 61 (23.2) 42 (16) 41 (15.5) 0.038 Cerevascular_dis, n (%) 74 ( 9.4) 22 (8.4) 23 (8.8) 29 (11) 0.537 PVD, n (%) 31 ( 3.9) 7 (2.7) 13 (4.9) 11 (4.2) 0391 Dementia, n (%) 27 ( 3.4) 8 (3) 9 (3.4) 10 (3.8) 0.895 DM, n (%) 269 (34.1) 75 (28.6) 97 (36.9) 97 (36.7) 0.074 HTN, n (%) 418 (52.9) 118 (44.9) 143 (54.4) 157 (59.5) 0.003 COPD, n (%) 68 ( 8.6) 26 (9.9) 21 (8) 21 (8) 0.664 CCI 3.0 (2.0, 5.0) 2.0 (1.0, 4.0) 3.0 (2.0, 5.0) 3.0 (2.0, 5.0) 0.006 Lab & Physiology Phosphate (mg/dL) 5.6 ± 2.3 5.4 ± 2.3 5.6 ± 2.4 5.9 ± 2.1 0.042 BAR 23.2 ± 13.8 10.8 ± 2.9 20.2 ± 3.2 38.6 ± 12.6 < 0.001 MAP (mmHg) 77.5 ± 14.8 77.3 ± 14.3 77.7 ± 14.9 77.3 ± 15.4 0.927 Hemoglobin (g/dL) 9.7 ± 2.2 10.2 ± 2.5 9.7 ± 2.0 9.2 ± 1.8 < 0.001 BUN (mg/dL) 56.9 ± 29.1 30.6 ± 9.4 52.9 ± 13.1 87.1 ± 25.8 < 0.001 Creatinine (mg/dL) 2.7 ± 1.5 2.0 ± 1.0 2.8 ± 1.5 3.2 ± 1.6 < 0.001 Albumin (g/dL) 2.6 ± 0.6 2.9 ± 0.6 2.6 ± 0.5 2.3 ± 0.5 < 0.001 CRP (mg/L) 67.4 (18.8,157.3) 56.9 (14.8, 142.9) 68.6 (20.7,165.2) 76.8 (20.8,171.5) 0.188 Severity & Treatment MV_CRRT, n (%) 625 (79.2) 216 (82.1) 206 (78.3) 203 (77.2) 0.343 APACHE II score 27.4 ± 8.0 26.0 ± 7.7 27.8 ± 8.1 28.4 ± 7.9 0.002 SOFA score 12.0 ± 3.5 11.2 ± 3.5 12.3 ± 3.4 12.5 ± 3.6 < 0.001 Outcomes STATUS 28, n (%) 494 (62.5) 147 (55.9) 159 (60.5) 188 (71.2) < 0.001 S28TIME (days) 18.3 ± 11.6 20.0 ± 11.2 18.8 ± 11.3 16.2 ± 11.9 < 0.001 BMI (Body Mass Index at ICU admission),MI (Myocardial Infarction),CHF (Congestive Heart Failure), Cerebrovascular_dis ( Cerebrovascular Disease),PVD ( Peripheral Vascular Disease),DM (Diabetes Mellitus), HTN ( Hypertension),COPD ( Chronic Obstructive Pulmonary Disease),CCI ( Charlson Comorbidity Index), Phosphate (CRRT initiation 0 h),BAR(Blood Urea Nitrogen to Serum Albumin Ratio),MAP (Mean Arterial Pressure), MAP (Mean Arterial Pressure),HB(Hemoglobin), BUN (Blood Urea Nitrogen),Alb(Serum albumin), CRP (C-Reactive Protein),MV_CRRT (Mechanical Ventilation during CRRT), STATUS28 (28-day Survival Status), S28TIME (28-day Survival Time) Table 2 Multivariable Cox Proportional Hazards Regression Analysis for 28-Day Mortality Variable Model 1 Model 2 Model 3 OR (95%Cl) P value OR (95%Cl) P value OR (95%Cl) P value BAR log2 1.37 (1.15~1.63) 0.001 1.36 (1.14~1.62) 0.001 1.60 (1.28~2.00) <0.001 BAR log2 Tertile T1( 1.80-3.96) 1(Ref) 1(Ref) 1(Ref) T2( 3.96-4.72) 1.21 (0.85~1.71) 0.289 1.18 (0.83~1.68) 0.714 1.24 (0.83~1.87) 0.293 T3( 4.72-7.07) 1.95 (1.36~2.80) <0.001 1.93 (1.34~2.77) <0.001 2.54 (1.62~3.98) <0.001 p for trend <0.001 <0.001 <0.001 BAR log2((Blood Urea Nitrogen to Serum Albumin Ratio), HTN ( Hypertension),Phosphate (CRRT initiation 0 h),CCI ( Charlson Comorbidity Index),CRP (C-Reactive Protein) Model 1:Non-adjusted Model 2:adjusted for Age,Sex Model3:adjusted for Age,Sex,HTN,Phosphate,CCI,Creatinine,CRP,SOFA score Additional Declarations No competing interests reported. Supplementary Files Supplementary1.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-6589198","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":453133425,"identity":"36a88143-d00e-47a7-b2c2-5f71afa54eac","order_by":0,"name":"Bufei Xie","email":"","orcid":"","institution":"The First People's Hospital of Longwan District","correspondingAuthor":false,"prefix":"","firstName":"Bufei","middleName":"","lastName":"Xie","suffix":""},{"id":453133427,"identity":"d16a095d-d2e1-405f-99a1-6e164e9d4d3d","order_by":1,"name":"Xiaoxiao Qu","email":"","orcid":"","institution":"The Second Affiliated Hospital \u0026 Yuying Children’s Hospital of Wenzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Xiaoxiao","middleName":"","lastName":"Qu","suffix":""},{"id":453133428,"identity":"6cf9b0f8-add2-47ee-a101-a0950993ee31","order_by":2,"name":"Huibo Wang","email":"","orcid":"","institution":"Hebei Medical University","correspondingAuthor":false,"prefix":"","firstName":"Huibo","middleName":"","lastName":"Wang","suffix":""},{"id":453133429,"identity":"1b2e85b8-e638-41c7-b2da-dc0c70e25336","order_by":3,"name":"Guosong Jiang","email":"","orcid":"","institution":"The 1st People's Hospital of Zhaotong City\u0026The Zhaotong Affiliated Hospital of Kunming Medical University","correspondingAuthor":false,"prefix":"","firstName":"Guosong","middleName":"","lastName":"Jiang","suffix":""},{"id":453133430,"identity":"29a1cea4-55c3-41d3-943c-53c8fe1e42db","order_by":4,"name":"Zimiao Zhu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuUlEQVRIiWNgGAWjYBACNmbm459/GNjwsLE3EKmFj50tjZmhIk2On+cAkVqASs2YGc4cMpackUC0wxjMHhe2HUjccPPxxhsMNTbRxGhJN57Zdidxw+20YguGY2m5DURoOSDB2/YMqCXHTIKx4TAxWhgbgFoOAx12hmgtzGzSPGcOA73PQ7QWNmbDGeBABvolgRi/yPef//jgAzgqD2+88aHGhrAWZGAgkUCKcogWUnWMglEwCkbByAAAF3o8/tRzuDsAAAAASUVORK5CYII=","orcid":"","institution":"CENTRAL BLOOD STATION OF WENZHOU","correspondingAuthor":true,"prefix":"","firstName":"Zimiao","middleName":"","lastName":"Zhu","suffix":""}],"badges":[],"createdAt":"2025-05-04 15:38:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6589198/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6589198/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83601974,"identity":"4812d520-5197-4a18-8112-46eaac5901ab","added_by":"auto","created_at":"2025-05-29 09:28:44","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":133094,"visible":true,"origin":"","legend":"\u003cp\u003eFlowchart of Patient Selection\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6589198/v1/a4b6f231606d098baeedb31a.png"},{"id":83601311,"identity":"67db22a5-4b4e-44e8-91fa-cac655365629","added_by":"auto","created_at":"2025-05-29 09:20:44","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":92218,"visible":true,"origin":"","legend":"\u003cp\u003eKaplan–Meier survival curves for 28-day mortality across BAR tertiles\u003c/p\u003e\n\u003cp\u003eKaplan–Meier survival curves showing 28-day cumulative survival probabilities for patients stratified by blood urea nitrogen to albumin ratio (BAR) tertiles (Q1 to Q3). The number of patients at risk for each group is displayed at specific time points during the follow-up period. The log-rank test for comparison among groups yields a P-value of \u0026lt;0.001, indicating a statistically significant difference in 28-day mortality. Notably, patients in the highest BAR tertile (Q3) exhibited the lowest cumulative survival rate over time.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6589198/v1/5c16c555a65dc9f356ddfded.png"},{"id":83601310,"identity":"5d44e742-ab27-49bf-87b8-01d096a9e333","added_by":"auto","created_at":"2025-05-29 09:20:44","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":132342,"visible":true,"origin":"","legend":"\u003cp\u003eSubgroup Analysis of 28-Day Mortality Risk Using Multivariable Cox Regression Model\u003c/p\u003e\n\u003cp\u003eForest plot displaying the adjusted hazard ratios (HR) and 95% confidence intervals (CI) for 28-day all-cause mortality across subgroups stratified by clinical and demographic characteristics. The analysis was performed using a multivariable Cox proportional hazards regression model, adjusting for age, sex, hypertension, creatinine, phosphate, C-reactive protein (CRP), Charlson comorbidity index (CCI), and SOFA score. The overall cohort included 790 patients, with 494 events (28-day deaths). Subgroups included sex, age, SOFA score (low vs. high), creatinine level, and CRP level. The P-values for interaction indicate no significant effect modification across subgroups (P for interaction \u0026gt; 0.05 ). The square markers represent point estimates of HRs, horizontal lines indicate 95% CI, and the diamond represents the overall effect.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6589198/v1/82998f18030bf3b422f307f2.png"},{"id":89356607,"identity":"7c0fae37-e24f-4d57-91d8-5c49cd747116","added_by":"auto","created_at":"2025-08-19 07:32:09","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1158269,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6589198/v1/a889b03b-32ce-4743-ac65-47b37fc9a908.pdf"},{"id":83601976,"identity":"15b567d2-165f-45a7-8072-ef94da20e4f5","added_by":"auto","created_at":"2025-05-29 09:28:44","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":43225,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Supplementary1.docx","url":"https://assets-eu.researchsquare.com/files/rs-6589198/v1/ffa9b4db757b70a6de73a7b1.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Association Between Blood Urea Nitrogen to Serum Albumin Ratio and 28-Day Mortality Risk in Sepsis Patients with AKI Undergoing Continuous Renal Replacement Therapy: A Secondary Analysis Based on a Retrospective Cohort Study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSepsis-associated acute kidney injury (AKI) is a common and life-threatening complication in critically ill patients, particularly those admitted to intensive care units (ICU)[1, 2]. This condition represents a severe intersection of systemic inflammation, organ dysfunction, and metabolic derangement, with high rates of morbidity and mortality[3, 4]. For patients requiring continuous renal replacement therapy (CRRT), the prognosis is particularly poor[5, 6]. Despite improvements in supportive care, early risk stratification remains challenging due to the lack of simple, reliable, and dynamic prognostic biomarkers.\u003c/p\u003e\n\u003cp\u003eThe blood urea nitrogen to albumin ratio (BAR) has recently gained attention as a composite marker reflecting both catabolic stress and nutritional status\u0026mdash;two critical determinants of outcome in critically ill populations[7, 8]. However, limited data exist regarding its prognostic value in patients with sepsis-associated AKI, especially those undergoing CRRT. Such patients face a particularly high risk of poor outcomes, given the interplay between sepsis-related inflammation, impaired renal function, and the challenges of continuous renal support.\u003c/p\u003e\n\u003cp\u003eTo address this gap, the present study aimed to investigate the association between BAR and 28-day all-cause mortality in patients with sepsis-associated AKI receiving CRRT. We hypothesized that higher BAR levels are independently associated with increased short-term mortality and that BAR may serve as a practical, accessible biomarker for early risk assessment in this high-risk population.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003eStudy Design and Data Source\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;This study was a secondary analysis of a publicly available, de-identified dataset originally provided by Seung Hyeok Han from the Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, Korea. The dataset was obtained from the Dryad Digital Repository (https://doi.org/10.5061/dryad.6v0j9) and includes patients admitted to the intensive care units (ICU) of Yonsei University Health System Severance Hospital and the National Health Insurance Service Medical Centre Ilsan Hospital between January 2009 and September 2016[9]. All patients received continuous renal replacement therapy (CRRT).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy Population\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eInclusion criteria for the original cohort were: (1) diagnosis of sepsis according to the Sepsis-3 definition (suspected infection and SOFA score \u0026ge;2)[10]; (2) acute kidney injury stage 2 based on the Acute Kidney Injury Network (AKIN) criteria[11]; (3) treatment with CRRT. Exclusion criteria included: age \u0026lt;18 years, pre-existing chronic kidney disease, prior dialysis or CRRT, pregnancy, postrenal obstruction, and history of kidney transplantation. The final analysis included 790 patients with sepsis-associated AKI who received CRRT(Fig 1).\u003c/p\u003e\n\u003cp\u003eCRRT protocol\u003c/p\u003e\n\u003cp\u003eNephrologists decided whether or not to initiate CRRT upon the development of sepsis with AKI in ICU patients. The indications for CRRT use included uncontrolled volume overload, intractable hyperkalaemia or metabolic acidosis. The type of CRRT used was continuous venovenous haemodiafiltration through the internal jugular, subclavian or femoral veins. CRRT was started at a blood flow rate of 100\u0026thinsp;ml/min and was increased up to 150\u0026thinsp;ml/min. The total effluent volume as a sum of the dialysis and replacement doses was targeted to deliver \u0026ge;35\u0026thinsp;ml/kg per h in all patients using a multiFiltrate machine (Fresenius Medical Care, Bad Homburg, Germany) or a PRISMAFLEX System (Baxter International, Lund, Sweden).\u003c/p\u003e\n\u003ch4\u003eData Collection\u003c/h4\u003e\n\u003cp\u003eClinical data including baseline demographics, comorbidities, laboratory test results (such as BUN, serum albumin, creatinine, and C-reactive protein), vital signs (blood pressure, heart rate), and clinical scores (APACHE II and SOFA) were collected. Patients were stratified into three groups based on the BUN/Alb ratio: Q1 (1.80\u0026ndash;3.96), Q2 (3.96\u0026ndash;4.72), and Q3 (4.72\u0026ndash;7.07).\u0026nbsp;\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003eOutcome\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eThe primary outcome was 28-day all-cause mortality following CRRT initiation.\u003c/p\u003e\n\u003ch4\u003eStatistical Analysis\u003c/h4\u003e\n\u003cp\u003ePatients were categorized into tertiles based on their blood urea nitrogen to albumin ratio (BAR) at the initiation of continuous renal replacement therapy (CRRT). Continuous variables were expressed as mean (standard deviation, SD) or median (interquartile range, IQR) according to their distribution, while categorical variables were reported as counts and percentages (n, %). Differences across BAR tertiles were assessed using one-way analysis of variance (ANOVA) or the Kruskal\u0026ndash;Wallis test for continuous variables, and the chi-square test for categorical variables.\u003c/p\u003e\n\u003cp\u003eMultivariable Cox proportional hazards regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between BAR and 28-day all-cause mortality. Three models were constructed: Model 1 was unadjusted; Model 2 was adjusted for age and sex; and Model 3 was further adjusted for hypertension, creatinine, phosphate, C-reactive protein (CRP), Charlson comorbidity index (CCI), and SOFA score. Restricted cubic spline models were applied to examine potential nonlinear dose-response relationships between BAR and mortality risk.\u003c/p\u003e\n\u003cp\u003eKaplan\u0026ndash;Meier survival curves were constructed to compare cumulative 28-day mortality across BAR tertiles, with significance assessed using the log-rank test. Subgroup analyses and interaction tests were performed using multivariable Cox models to evaluate potential effect modification.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll statistical analyses were performed using R software (version 4.2.2) and the Free Statistics analysis platform (version 2.1, Beijing, China). A two-sided P value \u0026lt; 0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eBaseline characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study included 790 critically ill patients with sepsis-associated acute kidney injury (AKI) undergoing CRRT. The mean age was 63.6 ± 14.1 years, and 490 patients (62.0%) were male. The mean APACHE II score was 23.3 ± 7.5, and the mean SOFA score was 8.6 ± 3.6.\u003cstrong\u003eTable 1\u003c/strong\u003e presents the baseline characteristics of patients stratified by BAR tertiles. Patients in the highest tertile (Q3) had significantly higher APACHE II scores (P \u0026lt; 0.001), SOFA scores (P \u0026lt; 0.001), and blood urea nitrogen levels (P \u0026lt; 0.001), as well as lower serum albumin concentrations (P \u0026lt; 0.001), compared to those in the lowest tertile (Q1).\u0026nbsp;\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003eUnivariate Analysis of Factors Associated with 28-Day Mortality\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003e\u003cstrong\u003eSupplementary Table 1\u003c/strong\u003e presents the results of univariate Cox proportional hazards regression analyses for 28-day all-cause mortality. Several clinical variables were significantly associated with increased mortality risk, including blood urea nitrogen to albumin ratio (BAR) (HR = 1.0092, 95% CI: 1.0037–1.0147, P \u0026lt; 0.001), phosphate (HR = 1.32, 95% CI: 1.13–1.54, P \u0026lt; 0.001), and SOFA score (HR = 1.11, 95% CI: 1.06–1.16, P \u0026lt; 0.001).In contrast, higher levels of albumin (HR = 0.41, 95% CI: 0.28–0.59, P \u0026lt; 0.001) and hemoglobin (HR = 0.95, 95% CI: 0.93–0.98, P \u0026lt; 0.001) were associated with a lower risk of death. Variables such as age, sex, white blood cell count, and comorbidities including hypertension and diabetes were not significantly associated with 28-day mortality (P \u0026gt; 0.05).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAssociation Between BAR and 28-Day Mortality\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMultivariable Cox regression analysis showed a significant association between BAR and 28-day all-cause mortality (\u003cstrong\u003eTable 2\u003c/strong\u003e). In the fully adjusted model, patients in the highest BAR tertile (Q3) had a 2.54-fold increased risk of death compared to those in the lowest tertile (Q1) (HR = 2.54, 95% CI: 1.62–3.98, P \u0026lt; 0.001). When treated as a continuous variable (log2-transformed), each doubling of BAR was associated with a 60% increased risk of 28-day mortality (HR = 1.60, 95% CI: 1.28–2.00, P \u0026lt; 0.001).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRestricted Cubic Spline Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eRestricted cubic spline modeling revealed a linear dose–response relationship between BAR and 28-day mortality (\u003cstrong\u003eSupplementary Figure 1\u003c/strong\u003e). The overall association was statistically significant (P \u0026lt; 0.001), with no evidence of non-linearity (P for non-linearity = 0.284).\u0026nbsp;\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003eKaplan–Meier Survival Analysis\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eKaplan–Meier survival curves indicated that patients in the highest BAR tertile had the lowest cumulative survival over 28 days (\u003cstrong\u003eFigure 2\u003c/strong\u003e; \u0026nbsp;P \u0026lt; 0.001). Survival probability declined progressively with increasing BAR tertiles.\u003c/p\u003e\n\u003ch3\u003e\u003cstrong\u003eSubgroup Analysis\u003c/strong\u003e\u003c/h3\u003e\n\u003cp\u003eSubgroup analyses demonstrated that the association between BAR and 28-day mortality was consistent across predefined strata, including age, sex, SOFA score, creatinine level, and CRP level (\u003cstrong\u003eFigure 3\u003c/strong\u003e). No significant interactions were detected (P for interaction \u0026gt; 0.05).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eFirst, this study demonstrates that the blood urea nitrogen to albumin ratio (BAR), a readily available clinical biomarker, is independently associated with 28-day mortality in patients with sepsis-associated acute kidney injury (AKI) undergoing continuous renal replacement therapy (CRRT). We found a consistent linear dose-response relationship between increasing BAR values and higher short-term mortality risk, supported by multivariable Cox regression and restricted cubic spline analyses. Second, the prognostic value of BAR remained robust across multiple clinical subgroups without significant interaction effects, suggesting its broad applicability in critically ill populations. Third, BAR reflects both catabolic stress and nutritional reserve\u0026mdash;two crucial prognostic domains in sepsis and AKI\u0026mdash;thus offering pathophysiological relevance alongside practical utility. Finally, the simplicity, accessibility, and strong predictive ability of BAR make it a promising candidate for early risk stratification and potential decision-making support in CRRT settings.\u003c/p\u003e \u003cp\u003eCompared to previous studies, our work addresses a significant gap in the literature. While BAR has been explored in general ICU populations, pneumonia, and cardiac failure, its prognostic utility in patients with sepsis-associated AKI receiving CRRT has not been well-established[\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Previous evidence was either limited by small sample sizes, inconsistent outcomes, or lacked adjustment for key confounders such as C-reactive protein, phosphate, and SOFA score. For example, studies by Cai S et al. (2022)[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] and Wang Y et al. (2023)[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] found that elevated BAR was associated with mortality in non-AKI patients with sepsis, but did not address the influence of continuous renal support or validate findings in high-risk AKI subgroups. Our study improves upon prior work by focusing on a well-defined, high-risk cohort using a large, multicenter dataset and rigorous statistical adjustment, thus enhancing the generalizability and clinical relevance of our findings.\u003c/p\u003e \u003cp\u003eBiologically, the association between elevated BAR and increased mortality in sepsis-associated AKI may be explained by multiple mechanisms. Blood urea nitrogen (BUN) levels reflect nitrogenous waste accumulation, which is exacerbated in renal dysfunction and systemic catabolism[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Hypoalbuminemia, on the other hand, indicates poor nutritional status, inflammation, and impaired liver function\u0026mdash;each of which has been linked to adverse outcomes in critically ill patients[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. A high BAR thus integrates both metabolic imbalance and diminished physiological reserve, which together may accelerate organ failure, compromise immune response, and worsen clinical trajectories in septic AKI[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe clinical advantages of our findings are notable. BAR can be rapidly calculated from two routine laboratory parameters, making it an easily implementable tool for early mortality risk assessment. In resource-limited settings or early triage scenarios, it could help prioritize patients for aggressive supportive care or closer monitoring. Additionally, as BAR incorporates both renal function and nutritional status, it may also aid in guiding individualized nutrition and fluid management strategies during CRRT.\u003c/p\u003e \u003cp\u003eNonetheless, this study has several limitations. First, its retrospective nature may introduce selection bias and unmeasured confounding. Second, dynamic changes in BAR during CRRT treatment were not captured; only baseline levels were analyzed. Third, residual confounding from unmeasured variables such as infection site, pathogen type, and use of vasopressors cannot be excluded. To mitigate these issues, we conducted rigorous multivariable adjustment and performed subgroup analyses to test robustness. Future prospective studies with repeated BAR measurements and expanded covariate sets are warranted to validate and extend these findings.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe BUN/Alb ratio is a significant predictor of 28-day mortality in septic patients with acute kidney injury (AKI) undergoing continuous renal replacement therapy (CRRT). For each one-unit increase in the BAR, the 28-day mortality risk increases significantly by 60%. This ratio provides valuable prognostic information and can help clinicians identify high-risk patients early, potentially guiding treatment decisions and improving patient outcomes.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch3\u003eData Availability\u003c/h3\u003e\n\u003cp\u003eThe data used in this study are publicly available from the Dryad repository. The dataset can be accessed through the following link: https://datadryad.org/stash. The dataset is under the citation of Jung, Su-Young J et al. (2019), \u0026quot;Data from: Phosphate is a potential biomarker of disease severity and predicts adverse outcomes in acute kidney injury patients undergoing continuous renal replacement therapy,\u0026quot; Dryad, Dataset, https://doi.org/10.5061/dryad.6v0j9.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors \u0026nbsp;contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBFX contributed to study design, data collection, statistical analysis, and manuscript drafting. XXQ, HBW, and GSJ assisted with data cleaning and management. ZMZ supervised the project and critically revised the manuscript. All authors read and approved the final version of the manuscript\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval and consent to participate\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe original study was approved by the Yonsei University Health System Severance Hospital Institutional Review Board (No. 4\u0026ndash;2016-1073). For our sec‑ondary study based on a public database, ethical approval was not required. A waiver of informed consent was obtained because of the nature of the study. This study conformed to the guidelines of the Helsinki Declaration.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll the authors have declared no competing interest.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eWang, D.H., et al., \u003cem\u003eAttributable mortality of acute kidney injury among critically ill patients with sepsis: a multicenter, retrospective cohort study.\u003c/em\u003e BMC Nephrol, 2024. \u003cstrong\u003e25\u003c/strong\u003e(1): p. 125.\u003c/li\u003e\n \u003cli\u003ePais, T., S. Jorge, and J.A. Lopes, \u003cem\u003eAcute Kidney Injury in Sepsis.\u003c/em\u003e Int J Mol Sci, 2024. \u003cstrong\u003e25\u003c/strong\u003e(11).\u003c/li\u003e\n \u003cli\u003eSun, J., et al., \u003cem\u003eSystemic Immune-Inflammation Index (SII) as a Predictor of Short-Term Mortality Risk in Sepsis-Associated Acute Kidney Injury: A Retrospective Cohort Study.\u003c/em\u003e Med Sci Monit, 2024. \u003cstrong\u003e30\u003c/strong\u003e: p. e943414.\u003c/li\u003e\n \u003cli\u003eTang, J., et al., \u003cem\u003eSystemic inflammation response index as a prognostic factor for patients with sepsis-associated acute kidney injury: a retrospective observational study.\u003c/em\u003e J Int Med Res, 2024. \u003cstrong\u003e52\u003c/strong\u003e(3): p. 3000605241235758.\u003c/li\u003e\n \u003cli\u003eLi, Y., et al., \u003cem\u003e[Construction of prognostic prediction model for patients with sepsis-induced acute kidney injury treated with continuous renal replacement therapy].\u003c/em\u003e Zhonghua Wei Zhong Bing Ji Jiu Yi Xue, 2024. \u003cstrong\u003e36\u003c/strong\u003e(12): p. 1268-1272.\u003c/li\u003e\n \u003cli\u003eFukuda, M., et al., \u003cem\u003eAssociation of Baseline Renal Function with Mortality in Patients with Sepsis Requiring Continuous Renal Replacement Therapy for Acute Kidney Injury: A Single-Center Retrospective Study.\u003c/em\u003e Blood Purif, 2023. \u003cstrong\u003e52\u003c/strong\u003e(2): p. 148-156.\u003c/li\u003e\n \u003cli\u003eHuang, Y., et al., \u003cem\u003eAssociation of the blood urea nitrogen to serum albumin ratio and all-cause mortality in critical ill acute ischemic stroke patients: a retrospective cohort study of MIMIC-IV database 3.0.\u003c/em\u003e Front Nutr, 2024. \u003cstrong\u003e11\u003c/strong\u003e: p. 1509284.\u003c/li\u003e\n \u003cli\u003eLi, W., Q. Huang, and K. Zhan, \u003cem\u003eAssociation of Serum Blood Urea Nitrogen to Albumin Ratio with in-Hospital Mortality in Patients with Acute Ischemic Stroke: A Retrospective Cohort Study of the eICU Database.\u003c/em\u003e Balkan Med J, 2024. \u003cstrong\u003e41\u003c/strong\u003e(6): p. 458-468.\u003c/li\u003e\n \u003cli\u003eJung, S.Y., et al., \u003cem\u003ePhosphate is a potential biomarker of disease severity and predicts adverse outcomes in acute kidney injury patients undergoing continuous renal replacement therapy.\u003c/em\u003e PLoS One, 2018. \u003cstrong\u003e13\u003c/strong\u003e(2): p. e0191290.\u003c/li\u003e\n \u003cli\u003eShankar-Hari, M., et al., \u003cem\u003eDeveloping a New Definition and Assessing New Clinical Criteria for Septic Shock: For the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3).\u003c/em\u003e Jama, 2016. \u003cstrong\u003e315\u003c/strong\u003e(8): p. 775-87.\u003c/li\u003e\n \u003cli\u003eRonco, C., et al., \u003cem\u003eImproving outcomes from acute kidney injury (AKI): Report on an initiative.\u003c/em\u003e Int J Artif Organs, 2007. \u003cstrong\u003e30\u003c/strong\u003e(5): p. 373-6.\u003c/li\u003e\n \u003cli\u003eZhang, S., et al., \u003cem\u003eBlood urea nitrogen to serum albumin ratio as a new indicator of disease severity and prognosis in idiopathic pulmonary artery hypertension.\u003c/em\u003e Respir Med, 2024. \u003cstrong\u003e227\u003c/strong\u003e: p. 107643.\u003c/li\u003e\n \u003cli\u003eZhang, L., et al., \u003cem\u003eBlood urea nitrogen to serum albumin ratio: a novel mortality indicator in intensive care unit patients with coronary heart disease.\u003c/em\u003e Sci Rep, 2024. \u003cstrong\u003e14\u003c/strong\u003e(1): p. 7466.\u003c/li\u003e\n \u003cli\u003eLiu, S., et al., \u003cem\u003eBlood urea nitrogen to serum albumin ratio as a new prognostic indicator in type 2 diabetes mellitus patients with chronic kidney disease.\u003c/em\u003e Sci Rep, 2024. \u003cstrong\u003e14\u003c/strong\u003e(1): p. 8002.\u003c/li\u003e\n \u003cli\u003eCai, S., et al., \u003cem\u003eAssociation between blood urea nitrogen to serum albumin ratio and in-hospital mortality of patients with sepsis in intensive care: A retrospective analysis of the fourth-generation Medical Information Mart for Intensive Care database.\u003c/em\u003e Front Nutr, 2022. \u003cstrong\u003e9\u003c/strong\u003e: p. 967332.\u003c/li\u003e\n \u003cli\u003eWang, Y., et al., \u003cem\u003ePrognostic impact of blood urea nitrogen to albumin ratio on patients with sepsis: a retrospective cohort study.\u003c/em\u003e Sci Rep, 2023. \u003cstrong\u003e13\u003c/strong\u003e(1): p. 10013.\u003c/li\u003e\n \u003cli\u003eHall, P.M., M. Schuman, and D.G. Vidt, \u003cem\u003eLaboratory tests of renal function.\u003c/em\u003e CRC Crit Rev Clin Lab Sci, 1976. \u003cstrong\u003e7\u003c/strong\u003e(1): p. 33-47.\u003c/li\u003e\n \u003cli\u003eNogi, K., et al., \u003cem\u003ePrognostic Value of Fractional Excretion of Urea Nitrogen at Discharge in Acute Decompensated Heart Failure.\u003c/em\u003e J Am Heart Assoc, 2021. \u003cstrong\u003e10\u003c/strong\u003e(16): p. e020480.\u003c/li\u003e\n \u003cli\u003eZheng, L.J., et al., \u003cem\u003eReduced serum albumin as a risk factor for poor prognosis in critically ill patients receiving renal replacement therapy.\u003c/em\u003e BMC Nephrol, 2021. \u003cstrong\u003e22\u003c/strong\u003e(1): p. 305.\u003c/li\u003e\n \u003cli\u003eBhatraju, P.K., M.M. Wurfel, and J. Himmelfarb, \u003cem\u003eTrajectory of Kidney Function: The Canary in Sepsis.\u003c/em\u003e Am J Respir Crit Care Med, 2020. \u003cstrong\u003e202\u003c/strong\u003e(9): p. 1211-1212.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table","content":"\u003cp\u003eTable 1 \u0026nbsp;Baseline Characteristics of Study Population\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"631\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTotal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eT1(\u003c/strong\u003eN= 263)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eT2(\u003c/strong\u003eN= 263)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eT3(\u003c/strong\u003eN= 264)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e(\u003c/strong\u003eN= 790)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e1.80-3.96\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e3.96-4.72\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e4.72-7.07\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDemographics\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eAge.Y\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e63.6 \u0026plusmn; 14.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e61.5 \u0026plusmn; 15.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e65.0 \u0026plusmn; 12.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e64.4 \u0026plusmn; 13.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.011\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eMale,n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e490 (62.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e157 (59.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e162 (61.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e171 (64.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.479\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eBMI (kg/m2)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e23.6 \u0026plusmn; 4.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e23.9 \u0026plusmn; 4.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e23.6 \u0026plusmn; 4.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e23.2 \u0026plusmn; 4.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.192\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eComorbidities\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eMI, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e72 ( 9.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e29 (11)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e22 (8.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e21 (8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.413\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eCHF, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e144 (18.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e61 (23.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e42 (16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e41 (15.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.038\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eCerevascular_dis, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e74 ( 9.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e22 (8.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e23 (8.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e29 (11)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.537\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003ePVD, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e31 ( 3.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e7 (2.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e13 (4.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e11 (4.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0391\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eDementia, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e27 ( 3.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e8 (3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e9 (3.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e10 (3.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.895\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eDM, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e269 (34.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e75 (28.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e97 (36.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e97 (36.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.074\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eHTN, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e418 (52.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e118 (44.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e143 (54.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e157 (59.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.003\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eCOPD, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e68 ( 8.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e26 (9.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e21 (8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e21 (8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.664\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eCCI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e3.0\u003c/p\u003e\n \u003cp\u003e(2.0, 5.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e2.0\u003c/p\u003e\n \u003cp\u003e(1.0, 4.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e3.0\u003c/p\u003e\n \u003cp\u003e(2.0, 5.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e3.0\u003c/p\u003e\n \u003cp\u003e(2.0, 5.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.006\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLab \u0026amp; Physiology\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003ePhosphate (mg/dL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e5.6 \u0026plusmn; 2.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e5.4 \u0026plusmn; 2.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e5.6 \u0026plusmn; 2.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e5.9 \u0026plusmn; 2.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.042\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eBAR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e23.2 \u0026plusmn; 13.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e10.8 \u0026plusmn; 2.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e20.2 \u0026plusmn; 3.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e38.6 \u0026plusmn; 12.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eMAP (mmHg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e77.5 \u0026plusmn; 14.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e77.3 \u0026plusmn; 14.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e77.7 \u0026plusmn; 14.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e77.3 \u0026plusmn; 15.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.927\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eHemoglobin (g/dL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e9.7 \u0026plusmn; 2.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e10.2 \u0026plusmn; 2.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e9.7 \u0026plusmn; 2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e9.2 \u0026plusmn; 1.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eBUN (mg/dL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e56.9 \u0026plusmn; 29.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e30.6 \u0026plusmn; 9.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e52.9 \u0026plusmn; 13.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e87.1 \u0026plusmn; 25.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eCreatinine (mg/dL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e2.7 \u0026plusmn; 1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e2.0 \u0026plusmn; 1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e2.8 \u0026plusmn; 1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e3.2 \u0026plusmn; 1.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eAlbumin (g/dL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e2.6 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e2.9 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e2.6 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e2.3 \u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eCRP (mg/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e67.4\u003c/p\u003e\n \u003cp\u003e(18.8,157.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e56.9\u003c/p\u003e\n \u003cp\u003e(14.8, 142.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e68.6\u003c/p\u003e\n \u003cp\u003e(20.7,165.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e76.8\u003c/p\u003e\n \u003cp\u003e(20.8,171.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.188\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSeverity \u0026amp; Treatment\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eMV_CRRT, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e625 (79.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e216 (82.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e206 (78.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e203 (77.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.343\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eAPACHE II score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e27.4 \u0026plusmn; 8.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e26.0 \u0026plusmn; 7.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e27.8 \u0026plusmn; 8.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e28.4 \u0026plusmn; 7.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eSOFA score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e12.0 \u0026plusmn; 3.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e11.2 \u0026plusmn; 3.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e12.3 \u0026plusmn; 3.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e12.5 \u0026plusmn; 3.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOutcomes\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eSTATUS 28, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e494 (62.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e147 (55.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e159 (60.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e188 (71.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003eS28TIME (days)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp\u003e18.3 \u0026plusmn; 11.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e20.0 \u0026plusmn; 11.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp\u003e18.8 \u0026plusmn; 11.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e16.2 \u0026plusmn; 11.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eBMI (Body Mass Index at ICU admission),MI (Myocardial Infarction),CHF (Congestive Heart Failure),\u003c/p\u003e\n\u003cp\u003eCerebrovascular_dis ( Cerebrovascular Disease),PVD ( Peripheral Vascular Disease),DM (Diabetes Mellitus),\u003c/p\u003e\n\u003cp\u003eHTN ( Hypertension),COPD ( Chronic Obstructive Pulmonary Disease),CCI ( Charlson Comorbidity Index),\u003c/p\u003e\n\u003cp\u003ePhosphate (CRRT initiation 0 h),BAR(Blood Urea Nitrogen to Serum Albumin Ratio),MAP (Mean Arterial Pressure),\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;MAP (Mean Arterial Pressure),HB(Hemoglobin), BUN (Blood Urea Nitrogen),Alb(Serum albumin),\u003c/p\u003e\n\u003cp\u003eCRP (C-Reactive Protein),MV_CRRT (Mechanical Ventilation during CRRT), STATUS28 (28-day Survival Status),\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eS28TIME (28-day Survival Time)\u003c/p\u003e\n\u003cp\u003eTable 2 \u0026nbsp;Multivariable Cox Proportional Hazards Regression Analysis for 28-Day Mortality\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariable\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;Model 1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eModel 2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eModel 3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"30\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eOR\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(95%Cl)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eOR\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(95%Cl)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eOR\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(95%Cl)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"29\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eBAR log2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.37 (1.15~1.63)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.36 (1.14~1.62)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1.60 (1.28~2.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"80\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eBAR log2\u003c/p\u003e\n \u003cp\u003eTertile\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"80\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eT1( 1.80-3.96)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1(Ref)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1(Ref)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e1(Ref)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"81\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003eT2( 3.96-4.72)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e1.21 (0.85~1.71)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e0.289\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e1.18 (0.83~1.68)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e0.714\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e1.24 (0.83~1.87)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e0.293\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"47\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd height=\"63\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\"\u003e\n \u003cp\u003eT3( 4.72-7.07)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\"\u003e\n \u003cp\u003e1.95 (1.36~2.80)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\"\u003e\n \u003cp\u003e1.93 (1.34~2.77)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\"\u003e\n \u003cp\u003e2.54 (1.62~3.98)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"47\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd height=\"47\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd height=\"47\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cem\u003ep\u0026nbsp;\u003c/em\u003efor trend\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"33\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eBAR log2((Blood Urea Nitrogen to Serum Albumin Ratio), HTN ( Hypertension),Phosphate (CRRT initiation 0 h),CCI ( Charlson Comorbidity Index),CRP (C-Reactive Protein)\u003c/p\u003e\n\u003cp\u003eModel 1:Non-adjusted\u003c/p\u003e\n\u003cp\u003eModel 2:adjusted for\u0026nbsp;Age,Sex\u003c/p\u003e\n\u003cp\u003eModel3:adjusted for Age,Sex,HTN,Phosphate,CCI,Creatinine,CRP,SOFA score\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Blood urea nitrogen to albumin ratio (BAR), Sepsis, Acute kidney injury (AKI), Continuous renal replacement therapy (CRRT), 28-day mortality","lastPublishedDoi":"10.21203/rs.3.rs-6589198/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6589198/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e: The blood urea nitrogen to albumin ratio (BAR) reflects both metabolic stress and nutritional status and may serve as a valuable prognostic marker in critically ill patients. However, its association with 28-day mortality in sepsis-related acute kidney injury (AKI) remains unclear, particularly among those receiving continuous renal replacement therapy (CRRT). This study aims to evaluate the relationship between BAR and short-term mortality and to explore its clinical relevance in risk stratification for critically ill patients.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e:This study was a secondary analysis based on a publicly available dataset. A total of 790 critically ill patients with sepsis-associated acute kidney injury who received continuous renal replacement therapy (CRRT) between January 2009 and September 2016 were included. The dataset was obtained from the Dryad repository. The blood urea nitrogen to albumin ratio (BAR) was calculated at the initiation of CRRT, and patients were categorized into tertiles based on BAR values. Cox proportional hazards regression models, restricted cubic spline analysis, and Kaplan–Meier survival curves were used to evaluate the association between BAR and 28-day mortality. To assess the robustness of the findings, subgroup analyses were conducted.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e: Among 790 patients, 494 (62.5%) died within 28 days. Higher blood urea nitrogen to albumin ratio (BAR) was significantly associated with increased 28-day mortality. Patients in the highest tertile (Q3) had a 2.54-fold increased risk compared to those in the lowest tertile (Q1) (HR = 2.54, 95% CI: 1.62–3.98,\u003cem\u003e P\u003c/em\u003e \u0026lt; 0.001). Restricted cubic spline analysis revealed a linear dose-response relationship. Kaplan-Meier curves showed significantly lower survival in the Q3 group (\u003cem\u003eP\u003c/em\u003e\u0026lt; 0.001). Subgroup analyses confirmed the robustness of the associations.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e: The blood urea nitrogen to albumin ratio (BAR) is an independent and clinically relevant predictor of 28-day mortality in septic patients with AKI undergoing CRRT. Elevated BAR is associated with significantly increased short-term mortality risk. Monitoring BAR may aid in early risk stratification and inform individualized treatment strategies in critically ill populations.\u003c/p\u003e","manuscriptTitle":"Association Between Blood Urea Nitrogen to Serum Albumin Ratio and 28-Day Mortality Risk in Sepsis Patients with AKI Undergoing Continuous Renal Replacement Therapy: A Secondary Analysis Based on a Retrospective Cohort Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-29 09:20:40","doi":"10.21203/rs.3.rs-6589198/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b14ca769-370f-481d-9cd1-64baeb495134","owner":[],"postedDate":"May 29th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-08-19T07:23:58+00:00","versionOfRecord":[],"versionCreatedAt":"2025-05-29 09:20:40","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6589198","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6589198","identity":"rs-6589198","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}