Prognostic significance of prediabetes in patients with acute myocardial infarction

Abstract Introduction Prediabetes is a metabolic disorder characterized by impaired glucose homeostasis that does not meet the diagnostic criteria for diabetes mellitus. The prognostic significance of prediabetes in patients with acute myocardial infarction (AMI) remains unclear. Aim To evaluate the long-term prognosis of patients after AMI who meet the laboratory criteria for prediabetes and to identify a subgroup of patients with the highest cardiovascular risk. Methods and results A retrospective analysis was conducted on a cohort of 6,990 patients from four centers hospitalized for acute myocardial infarction between 2010 and 2023. The mean age of the study population was 66.4 ± 12.3 years, and 67% were men. Among patients with prediabetes—defined by glycated hemoglobin (HbA1c) levels of 38–47 mmol/mol—we identified a subgroup of the highest-risk individuals with fasting and admission plasma glucose levels 7 mmol/L and 11 mmol/L, respectively. Using data obtained from the national health registry (ÚZIS), we assessed long-term outcomes, including all-cause mortality, recurrent myocardial infarction, stroke, coronary revascularization, and heart failure, and compared them with patients without prediabetes. From the non-prediabetic cohort, we excluded individuals with very low HbA1c values ( 31 mmol/mol), which are considered to be a marker of another serious underlying condition. Patients with prediabetes and elevated fasting or admission plasma glucose demonstrated higher all-cause mortality (HR 1.6; p 0.001) and a higher incidence of heart failure (HR 1.7; p 0.001) compared to non-prediabetic patients. No increased risk of 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) was observed between these groups. Suvival of subjects with prediabetes without elevated fasting or admission glucose did not differ from the non - prediabetic subjets (FIg 1). Conclusion Patients with prediabetes identified only by glycated hemoglobin (HbA1c) levels have a prognosis similar to that of individuals without prediabetes. However, within this group, those who also have elevated fasting or admission plasma glucose form a distinct high-risk subgroup. These patients have significantly higher mortality and a greater risk of developing heart failure. In contrast, this subgroup does not show an increased risk of recurrent myocardial infarction, stroke, or the need for coronary revascularization.