Red blood cell distribution width is associated with short-term mortality in critically ill patients with type 2 diabetes mellitus

Abstract Red blood cell distribution width (RDW) is associated with increased mortality in several diseases. However, the relationship between RDW fluctuations and the prognosis of critically ill patients with type 2 diabetes mellitus (T2DM) has not been reported. This study investigated the association between baseline RDW levels and dynamic changes and short-term mortality in critically ill patients with T2DM. All critically ill patients meeting the diagnostic criteria for T2DM in the Medical Information Mart for Intensive Care IV database were retrospectively analyzed. Logistic and Cox regression, Kaplan–Meier survival, and subgroup analyses were used to determine the association between baseline RDW and short-term mortality in critically ill patients with T2DM. Generalized additive mixed models were then used to compare trends in RDW over time between survivors and non-survivors. This study enrolled 6,299 patients with a 28-day mortality rate of 18.4%. Kaplan–Meier analysis showed higher 28-day and 60-day mortality ( P <0.001) in the high baseline RDW group. High baseline RDW was revealed by multivariate logistic and Cox regression models as an independent risk factor for in-hospital, 28-day, and 60-day mortality in critically ill patients with T2DM. An association between elevated baseline RDW and 28-day mortality was observed in all subgroup analyses. The generalized summation mixed-effects model results showed a significant difference in RDW between the surviving and non-surviving groups within 48 h of admission to the intensive care unit (ICU). Moreover, this difference increased with time (β=0.034, P =0.003). Elevated baseline RDW at ICU admission was associated with high short-term mortality in critically ill patients with T2DM, an association that remained significant within 48 h of patient admission to the ICU. Moreover, dynamic monitoring of RDW may help predict short-term mortality in critically ill patients with T2DM. However, this finding requires further validation in prospective studies.