Association of Glycemic Variability with Mortality among Septic Patients with Coronary Artery Disease: A Multicenter Cohort Study

Background Septic patients with coronary artery disease (CAD) face elevated mortality risks, potentially exacerbated by glycemic variability (GV). This study aimed to investigate the association between GV and in-hospital and 1-year mortality in septic patients with CAD. Methods We conducted a retrospective analysis using data from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database as the discovery cohort and the Tianjin Health and Medical Database Platform (THMDP) as the validation cohort. Patients with sepsis and CAD who had at least three blood glucose measurements during their ICU stay were included. Glycemic variability was defined as the coefficient of variation of blood glucose levels, categorized into quartiles (Q1–Q4). The primary outcome was in-hospital mortality, with 1-year mortality as a secondary outcome. Cox proportional hazards models were used to assess the association between GV and mortality. Results Higher GV was significantly associated with increased in-hospital mortality in both cohorts (MIMIC-IV: n = 2599) adjusted Hazard Ratio (HR) 4.06, 95% CI 1.72-9.58, P = 0.001; THMDP: n = 2,797, adjusted HR 1.56, 95% CI 1.25-1.93, P = 0.001). A pooled two-cohort analysis confirmed a significant association with in-hospital mortality (adjusted HR for Q4 vs Q1: 1.65, 95% CI 1.34-2.03, P = 0.001), while the association with 1-year mortality was weaker (adjusted HR 1.24, 95% CI 0.89-1.73, P = 0.204). Restricted cubic spline (RCS) analyses revealed a nonlinear relationship between GV and in-hospital mortality ( P for nonlinearity < 0.001). Kaplan-Meier (KM) survival curves showed reduced survival probability in the highest GV group. Conclusions Higher GV is independently associated with increased in-hospital mortality among septic patients with CAD, but no significant association was found with 1-year mortality. These findings suggest that stabilizing GV may be a critical area for clinical management and warrants further investigation. Monitoring and managing GV may improve outcomes in this patient population.