The prognostic value of red cell distribution width-to-albumin ratio for 28-day mortality in sepsis patients: a multicenter analysis based on the eICU Collaborative Research Database.

Abstract

Sepsis remains one of the leading causes of death in intensive care units worldwide. The red blood cell distribution width-to-albumin ratio (RAR) is calculated by dividing the red blood cell distribution width (%) by serum albumin (g/dl); this indicator combines information on inflammation and nutritional status and is closely associated with the prognosis of critically ill patients. This study aimed to explore the association between RAR and 28-day all-cause mortality in adult patients with sepsis. This retrospective, multicentre cohort study extracted 13,888 adult patients meeting sepsis criteria from the eICU CRD database. Primary outcomes comprised 28-day ICU all-cause mortality and in-hospital all-cause mortality. Cox proportional hazards models assessed the independent association between RAR and mortality. Subgroup analyses and restricted cubic spline validation confirmed the consistency and nonlinear nature of this association. A total of 13,888 patients with sepsis were included and divided into low-RAR and high-RAR groups based on the median RAR value (5.9). The 28-day mortality rate in the high-RAR group was significantly higher than that in the low-RAR group (23.0% vs 9.9%, P < 0.001). After multivariable adjustment, high RAR was independently associated with increased mortality (HR 1.50, 95% CI 1.36-1.64, P < 0.001). As a continuous variable, each unit increase in RAR was associated with an 8% higher risk of mortality (HR 1.08, 95% CI 1.07-1.10, P < 0.001). Subgroup analyses confirmed consistency across age, sex, and comorbidity stratifications. A non-linear dose-response relationship was observed, with mortality risk increasing progressively with higher RAR levels. Elevated RAR levels at admission are independently associated with increased 28-day mortality in patients with sepsis. As an easily accessible and low-cost indicator, RAR may prove to be a useful risk stratification tool in clinical practice; however, its clinical value in resource-limited settings still needs to be further validated through prospective validation and cost-effectiveness studies.