Prediabetes affects a substantial proportion of patients admitted with acute myocardial infarction (AMI), yet its prognostic significance remains unclear. A retrospective multicenter study published in European Heart Journal Acute Cardiovascular Care evaluated long-term outcomes among patients with AMI to identify higher-risk prediabetes subgroups.

The analysis included 6,990 patients hospitalized with AMI across four centers between 2010 and 2023. The mean age was 66.4 ± 12.3 years, and 67% were men. Prediabetes was defined by glycated hemoglobin (HbA1c) levels of 38-47 mmol/mol. Among patients with prediabetes, the high-risk subgroup was defined by fasting plasma glucose >7 mmol/L and admission plasma glucose >11 mmol/L. Endpoints included all-cause mortality, recurrent myocardial infarction, stroke, coronary revascularization, and heart failure.

Findings

• All-cause mortality was higher among patients with prediabetes and elevated fasting or admission glucose (HR 1.6; p<0.001).
• Heart failure incidence was also higher in the high-risk prediabetes subgroup (HR 1.7; p<0.001).
• No increased risk was observed for recurrent myocardial infarction (HR 0.7; p=0.122), stroke (HR 0.7; p=0.23), or coronary revascularization (HR 0.95; p=0.73).
• Survival among patients with prediabetes without elevated fasting or admission glucose did not differ from patients without prediabetes.

These findings suggest that HbA1c alone may not fully identify higher-risk patients with prediabetes after AMI. Elevated fasting or admission glucose identified a subgroup with higher mortality and heart failure risk.