Objective To investigate the relationship between glycemic variability (GV) and all-cause mortality in patients with severe ischemic stroke (IS).

Methods Patients diagnosed with IS in the intensive care unit (ICU) were selected from the MIMIC-Ⅳ database for a retrospective cohort study. GV was quantified using the coefficient of variation (CV), defined as the ratio of the standard deviation of blood glucose value to the mean blood glucose value. Cox proportional hazards models were used to investigate the association between GV and all-cause mortality. Restricted cubic splines (RCS) were applied to model potential nonlinear relationships between GV and outcomes, and Kaplan-Meier survival curves were used to compare survival among patients with different GV levels. Receiver operating characteristic (ROC) curves were used to assess the predictive utility of GV for all-cause mortality. Subgroup analyses were conducted to assess the robustness of the findings.

Results A total of 2,443 patients with IS were included. Multivariate Cox regression analysis showed that in the fully adjusted model, when analyzed as a continuous variable, CV was significantly and positively associated with the risk of 28-day, 90-day, 180-day, and 365-day all-cause mortality, with hazard ratios (HR) of 3.37, 3.35, 2.84, and 2.91, respectively (P < 0.001). RCS analysis revealed a positive linear association between CV and the risk of death across all time windows (overall P < 0.001, non-linear P > 0.05). Both the Kaplan-Meier survival curve and the fully adjusted Cox regression analysis showed that there was no statistically significant correlation between CV and the risk of ICU all-cause mortality (P > 0.05).

Conclusions GV is an independent risk factor for both short-term and long-term all-cause mortality in patients with severe IS. These findings emphasize the importance of optimizing glycemic control in severe IS patients, suggesting that by reducing GV and maintaining glucose homeostasis, which may help improve patient outcomes.

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