Association between haemoglobin-to-red blood cell distribution width ratio at admission and all-cause mortality in adult patients with sepsis in an intensive care unit: a secondary analysis of the MIMIC-IV database

Objective The association between haemoglobin-to-red blood cell distribution width ratio (HRR) and all-cause mortality remains poorly understood. This study aimed to examine the influence of HRR at the time of admission mortality over 1 year and 30 days in patients with sepsis. Design This was a secondary analysis. Setting This study was conducted in intensive care units (ICUs). Participants Adult patients with sepsis were identified and included from an intensive care database based on eligibility criteria. Primary outcome and measure The primary outcome was the rate of death within 1 year. The secondary outcome was the death rate within 30 days. Results A total of 4233 patients with sepsis who met the inclusion criteria were analysed, excluding those ineligible. These participants were divided into quartiles based on their HRR at admission. The overall mortality rates at 1 year and 30 days were 42.9% and 25.5%, respectively. A significant inverse association was observed between HRR quartiles and all-cause mortality (p<0.001). Pairwise comparisons using Kaplan-Meier analysis showed significant differences in 1-year mortality rates across the quartiles. However, no significant difference was detected in 30-day mortality between the Q3 and Q4 groups (p=0.222). Multivariate Cox regression analysis demonstrated that a higher HRR at ICU admission was independently associated with reduced mortality at 1 year (HR, 0.935; 95% CI 0.913 to 0.958; p<0.001) and 30 days (HR, 0.969; 95% CI 0.939 to 0.999; p=0.043). Furthermore, restricted cubic spline models indicated a non-linear relationship between HRR and mortality at both 1 year and 30 days (p<0.001 for both). Conclusions This retrospective analysis demonstrated that the HRR at the time of admission was a significant prognostic marker for long-term mortality in patients with sepsis.