Association between Red Blood Cell Distribution Width and In-Hospital Mortality among Congestive Heart Failure Patients with Diabetes among Patients in the Intensive Care Unit: A Retrospective Cohort Study

Background. Elevated red blood cell distribution width (RDW) levels are strongly associated with an increased risk of mortality in patients with congestive heart failure (CHF). Additionally, heart failure has been closely linked to diabetes. Nevertheless, the relationship between RDW and in-hospital mortality in the intensive care unit (ICU) among patients with both congestive heart failure (CHF) and diabetes mellitus (DM) remains uncertain. Methods. This retrospective study utilized data from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database, a comprehensive critical care repository. RDW was assessed as both continuous and categorical variables. The primary outcome of the study was in-hospital mortality at the time of hospital discharge. We examined the association between RDW on ICU admission and in-hospital mortality using multivariable logistic regression models, restricted cubic spline analysis, and subgroup analysis. Results. The cohort consisted of 7,063 patients with both DM and CHF (3,135 females and 3,928 males). After adjusting for potential confounders, we found an association between a 9% increase in mortality rate and a 1 g/L increase in RDW level (OR = 1.09; 95% CI, 1.05 similar to 1.13), which was associated with 11 and 58% increases in mortality rates in Q2 (OR = 1.11, 95% CI: 0.87 similar to 1.43) and Q3 (OR = 1.58, 95% CI: 1.22 similar to 2.04), respectively, compared with that in Q1. Moreover, we observed a significant linear association between RDW and in-hospital mortality, along with strong stratified analyses to support the findings. Conclusions. Our findings establish a positive association between RDW and in-hospital mortality in patients with DM and CHF.