Association between glucose-to-platelet ratio and all-cause mortality in critically ill patients with acute myocardial infarction: a retrospective cohort study.

BACKGROUND: Acute myocardial infarction (AMI) in critically ill patients is associated with high mortality. The glucose-to-platelet ratio (GPR), derived from routine early glucose and platelet measurements, may provide additional prognostic information, but its value in ICU patients with AMI remains unclear. METHODS: This retrospective cohort study included 4,676 adult ICU patients with AMI from the MIMIC-IV version 3.1 database. GPR was calculated as the mean glucose concentration during the first 24 h after ICU admission divided by the first platelet count recorded within the same period. Outcomes were 30-day and 360-day all-cause mortality from ICU admission. Associations were assessed using multivariable Cox proportional hazards models, restricted cubic splines, and exploratory internally validated prediction models. RESULTS: Among 4,676 patients, the 30-day and 360-day mortality rates were 19.6% and 29.1%, respectively. In the fully adjusted model, each 1-unit increase in GPR was associated with higher 30-day mortality (HR, 1.10; 95% CI, 1.05-1.15) and 360-day mortality (HR, 1.12; 95% CI, 1.07-1.16; both P < 0.001). Compared with the lowest tertile, the highest GPR tertile was associated with increased 30-day mortality (HR, 1.60; 95% CI, 1.35-1.90) and 360-day mortality (HR, 1.29; 95% CI, 1.12-1.47; both P < 0.001). Spline analyses suggested nonlinearity only for 30-day mortality. In exploratory internal validation, ridge regression incorporating GPR achieved an area under the receiver operating characteristic curve of 0.816. CONCLUSIONS: Higher GPR was independently associated with increased short- and long-term all-cause mortality in critically ill patients with AMI. GPR may complement conventional variables for early ICU risk stratification.