An Early Longitudinal Decrease in Platelet Count Is Associated With Poor Prognosis in Acute Myocardial Infarction Patients: A Multicenter Retrospective Study

Background Limited data are available on the association between early longitudinal changes in platelet count and mortality. Objective This study aimed to compare the early longitudinal changes in platelet count between survivors and non‐survivors. Methods This was a retrospective multi‐center cohort study using data from the eICU Collaborative Research Database. A total of 6,769 patients diagnosed with AMI were included in the study. The analysis employed a Generalized Additive Model (GAM) and a Generalized Additive Mixed Model (GAMM) to compare longitudinal changes in platelet count between survivors and non‐survivors. Results The ICU 28‐day and ICU 7‐day all‐cause mortality were 6.1% and 4.6%, respectively. During the first 5 days of ICU admission, GAM showed that non‐survivors exhibited a significantly greater decline in platelet count than survivors. Specifically, the GAMM results showed that the difference in platelet count between ICU 28‐day non‐survivors and ICU 28‐day survivors increased by an average of 15.4 × 10 9 /L daily (95% Confidence Interval [CI], 14.1 to 16.7; p < 0.001). Similarly, the difference in platelet count between ICU 7‐day non‐survivors and ICU 7‐day survivors increased by an average of 18.0 × 10 9 /L daily (95% CI, 16.1−19.8; p < 0.001). Conclusions An early longitudinal decline in platelet count was associated with a poor prognosis in patients with AMI. However, this study is observational, and causality cannot be inferred.