Routine oral glucose tolerance test to improve risk stratification in acute coronary syndrome patients

Background Abnormalities in blood glucose regulation are highly prevalent in patients with ACS and are associated with worse outcomes. Routine screening methods, such as fasting plasma glucose (FPG) and HbA1c, often fail to detect intermediate glucose disturbances like impaired glucose tolerance (IGT) or early diabetes, both of which are key to early intervention. Methods We analyzed two cohorts of ACS patients: one hospitalized during 2021–2022 (n=125) and screened using only FPG and HbA1c, and another hospitalized during 2023–2024 (n=125), which incorporated OGTT alongside FPG and HbA1c at hospital discharge. Patients were classified as euglycemic, prediabetic, or diabetic according to current ADA criteria. The proportion of patients identified within each glucose phenotype was compared between the two cohorts. Markers of inflammatory burden, atherosclerotic burden and myocardial infarction severity were assessed across glucose phenotypes identified through the glycemic screening. Results The two cohorts were comparable in age, BMI, and comorbidities, ensuring homogeneity between groups. In the 2023–2024 cohort, which was routinely screened with OGTT in addition to FPG and HbA1c, a significantly higher proportion of DM cases, including newly diagnosed DM, were identified compared to the 2021–2022 cohort (37 [29.6%] vs 58 [46.4%], p <0.006). Conversely, the prevalence of euglycemia was significantly lower in the 2023–2024 cohort (44 [35.2%] vs 14 [11.2%], p <0.001). Patients in the prediabetic and DM groups identified in the 2023–2024 ACS cohort featured significantly higher levels of inflammatory markers, including epicardial adipose tissue (EAT, p <0.001) and hs-C Reactive Protein (p = 0.004), worse LVEF (p = 0.011), higher troponin peak (p = 0.011), a greater prevalence of suspected peripheral artery disease (diagnosed with Ankle-Brachial Index [ABI], p <0.001), and an increased need for CABG compared to euglycemic patients. Among prediabetic patients, those identified through the comprehensive screening in the 2023–2024 cohort exhibited significantly lower ABI (1.21 ± 0.09 vs 1.01 ± 0.24, p <0.001), higher EAT (6.41 ± 2.28 vs 7.78 ± 2.58, p = 0.004), and reduced eGFR (73.2 ± 22.2 vs 63 ± 23.8, p = 0.04) compared to their counterparts in the 2021–2022 cohort. The length of hospital stay was comparable between the two cohorts. Conclusions The routine implementation of OGTT significantly improved glucose phenotyping in ACS patients, enabling the identification of high-risk profiles such as IGT and early-stage DM. These high-risk phenotypes were associated with greater inflammatory and atherosclerotic burden, as well as with more severe myocardial infarction compared to euglycemic patients. OGTT implementation did not prolong hospital stays, supporting its feasibility in clinical practice. These findings underscore the importance of performing the OGTT to improve risk stratification, ultimately enhancing outcomes in ACS patients.