Association between the serum albumin-creatinine ratio and 28-day intensive care unit mortality among patients with sepsis: a multicenter retrospective cohort study

Introduction: Sepsis is a substantial global health challenge with a considerable disease burden. Despite advancements in sepsis research, the mortality rates associated with this condition remain high. The relationship between the serum albumin-to-creatinine ratio (sACR) and mortality in patients with sepsis remains unclear. Therefore, this study aimed to investigate the association between the sACR and 28-day mortality in intensive care unit (ICU) patients with sepsis. Methods: In this retrospective cohort study, we used data sourced from the eICU Collaborative Research Database. The primary exposure variable was sACR, and the primary outcome measure was mortality within 28 days after ICU admission. Statistical analyses included univariate and multivariate logistic regression models, generalized additive models, and two-piecewise linear regression models, which were employed to explore non-linear relationships and threshold effects between sACR and mortality. Results: The study cohort comprised 9,690 ICU patients with sepsis, with a 28-day mortality rate of 9.99%. The results of the multivariate logistic regression model indicated that elevated sACR levels were significantly associated with a reduced risk of mortality (odds ratio = 0.78, 95% confidence interval: 0.71-0.87, p < 0.001), even after adjusting for potential confounding variables. Curve fitting revealed a non-linear relationship between sACR and 28-day mortality, with an inflection point of 4.79. Discussion: This study demonstrated that sACR is an independent risk factor for 28-day mortality in ICU patients with sepsis, exhibiting a non-linear negative dose-response relationship and a threshold effect. These findings may serve as early warning indicators in high-risk populations.