Red Blood Cell Distribution Width is Associated with Short-term Mortality in Critically Ill Patients with Type 2 Diabetes Mellitus

Abstract

Background: Red blood cell distribution width (RDW) is associated with increased mortality in many 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. Methods: 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. Results: 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 death 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). Conclusions: 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.