# Associations between red cell distribution width and in-hospital mortality in congestive heart failure patients with chronic obstructive pulmonary disease: a retrospective cohort study

## TL;DR

This study finds that higher red cell distribution width is linked to increased in-hospital mortality in patients with both heart failure and COPD.

## Contribution

The study identifies a novel association between RDW and mortality in patients with co-occurring congestive heart failure and COPD.

## Key findings

- RDW was positively associated with in-hospital mortality (OR = 1.07, p < 0.001).
- The highest RDW quartile had 1.62 times higher mortality odds than the lowest quartile.
- The relationship remained consistent across subgroup analyses.

## Abstract

Recent studies have identified a co-occurrence of chronic obstructive pulmonary disease and congestive heart failure in ICU patients. Abnormal red cell distribution width (RDW) frequently manifests in critically ill patients, but its clinical significance remains a subject of debate. This study aims to investigate the relationship between RDW and in-hospital mortality in patients with concurrent congestive heart failure and chronic obstructive pulmonary disease.

We conducted a retrospective cohort study using the Medical Information Mart for Intensive Care (MIMIC) IV version 2.0 database. RDW levels were assessed within 24 h of admission. The impact of RDW at ICU admission on in-hospital mortality was analyzed through multivariable logistic regression models, generalized additive models, and subgroup analysis.

We enrolled 6,309 patients with congestive heart failure and concomitant chronic obstructive pulmonary disease, with an in-hospital mortality rate of 12.4% (783/6,309). The fully adjusted model revealed a positive association between RDW and in-hospital mortality in congestive heart failure patients with concurrent chronic obstructive pulmonary disease, even after accounting for confounding factors (OR = 1.07, 95% CI: 1.03–1.12, p < 0.001). When comparing the highest quartile (Q4) to the lowest quartile (Q1), the odds ratio (OR) was 1.62, with a 95% confidence interval (CI) of 1.17–2.22, p = 0.003. We observed a linear relationship between RDW and in-hospital mortality, which remained consistent in subgroup analysis.

Our data suggest that RDW is positively associated with in-hospital mortality in patients with both congestive heart failure and chronic obstructive pulmonary disease. At the same time, large prospective research and longer follow-up time are required to further validate the findings of this study.