Association of hemoglobin-to-red blood cell distribution width ratio with mortality in critically Ill patients with heart failure and acute kidney injury: insights from the MIMIC-IV database

BackgroundThe association between the hemoglobin-to-red cell distribution width ratio (HRR) and mortality in critically ill patients with heart failure (HF) and acute kidney injury (AKI) remains uncertain. This research focuses on exploring the association between HRR and both short-term and long-term all-cause mortality in these patients.MethodsParticipants were selected from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database and categorized into tertiles based on HRR values. The primary endpoint was 28-days ICU all-cause mortality. Secondary endpoints included 28-days hospital and 90-days hospital all-cause mortality. Cox proportional hazards models and restricted cubic splines were used to analyze the association between HRR and mortality in patients with HF and AKI. Kaplan-Meier survival analysis estimated endpoint differences across tertiles.ResultsA total of 7561 patients were included, with 55.5% being male (n=4199). Cox proportional hazards analysis showed a significant link between HRR and both short-term and long-term mortality in critically ill patients with HF and AKI. This association remained significant after adjusting for confounders. The restricted cubic splines model demonstrated a linear relationship between a higher HRR index and a reduced mortality risk. Kaplan-Meier survival analysis revealed significant differences in short-term and long-term mortality among the tertile groups.ConclusionThe study results show a strong association between lower HRR and increased short-term and long-term mortality in critically ill patients with heart failure and AKI. HRR proves to be a valuable and cost-effective marker for identifying high-risk patients.