Association between red blood cell distribution width-platelet ratio and mortality in patients with sepsis-induced coagulopathy from the MIMIC-IV database: a retrospective cohort study

BACKGROUND: This study aims to investigate the association between the Red cell distribution width to platelet count ratio (RPR) and adverse outcomes in critically ill patients with sepsis-induced coagulopathy (SIC). METHODS: Clinical data from 7,014 patients admitted to the Intensive Care Unit (ICU) with SIC were extracted from the MIMIC-IV (3.1) database. The study population was divided into four groups based on quartiles of RPR. The primary outcome was 28-day all-cause mortality, and the secondary outcome was ICU mortality. The relationship between RPR and adverse outcomes was explored using Kaplan-Meier curves, Cox proportional hazards regression, restricted cubic spline curves, and subgroup analyses. RESULTS: In this study, a total of 7,014 SIC patients were enrolled. RPR was independently associated with both 28-day all-cause mortality and ICU mortality (all p < 0.01). According to Kaplan-Meier curve analysis, the high RPR (≥0.21) group exhibited worse 28-day survival (Log-rank test, p < 0.001). Restricted cubic spline (RCS) curves revealed a nonlinear relationship between RPR and mortality risk (all p for overall < 0.001, all p for nonlinear < 0.05). Threshold effect analysis showed that to the right of the inflection point, the increase in RPR is significantly associated with an increased risk of all-cause mortality in patients. (HR: 1.83, 95% CI: 1.52-2.20). This association remained stable across all subgroups without significant interaction effects. CONCLUSION: The RPR exhibits a "J-shaped" relationship with both 28-day all-cause mortality and ICU mortality in patients with SIC. Both elevated and reduced RPR indices may be associated with early poor prognosis in patients with sepsis-induced coagulopathy. CLINICAL TRIAL NUMBER: Not applicable.