In‐hospital changes in the red blood cell distribution width and mortality in critically ill patients with heart failure.

Aims: A high red blood cell distribution width (RDW) at admission or discharge is associated with a worse prognosis in hospitalized patients with heart failure (HF), and the prognostic value of the in‐hospital change in RDW (∆RDW) remains debatable. Methods and results: We included 5514 patients with critical illness and HF from the MIMIC‐IV database. The ΔRDW was calculated by the RDW at discharge minus that at admission. Clinical outcomes included all‐cause mortality at 90 day, 180 day, and 1 year after discharge. The median age of the patients was 73.91 years, and 46.37% were women. Kaplan–Meier curve and Cox regression analyses were used to examine the association between the ΔRDW and all‐cause mortality at different time points. A multivariable Cox proportional hazard model showed that the ΔRDW (per 1% increase) was independently associated with all‐cause mortality at 90 day, 180 day, and 1 year after adjusting for confounding factors (hazard ratio [HR] = 1.17, 95% confidence interval [CI] = 1.13–1.21, P < 0.001; HR = 1.17, 95% CI = 1.14–1.20, P < 0.001; and HR = 1.18, 95% CI = 1.15–1.20, P < 0.001, respectively). Restricted cubic splines showed a non‐linear relationship between the ΔRDW and the risk of clinical outcomes. High ΔRDW was associated with a high risk of mortality at different time points. A subgroup analysis showed that this positive association remained consistent in pre‐specified subgroups. Conclusions: Our study suggests that an increased RDW during hospitalization is independently associated with short‐ or long‐term all‐cause mortality in critical‐ill patients with HF. [ABSTRACT FROM AUTHOR]