Background: Previously undetected dysglycaemia is common among patients with acute coronary syndromes (ACSs). The aim of this study was to identify the most reliable method of diagnosing type 2 diabetes mellitus (T2DM) and prediabetes in ACS patients.
Methods: Patients admitted to the coronary care unit with ACSs and no previous history of T2DM were consecutively included in the study. Glucose metabolism was measured by glycated haemoglobin (HbA1c), fasting plasma glucose (FPG) and 2-hour plasma glucose (2hPG) with a standard oral glucose tolerance test during hospital admission, and this process was repeated 3 months later. In this study, the diagnosis of T2DM required at least two measurements above the diabetes cut-off point according to current American Diabetes Association and World Health Organization criteria.
Results: A total of 250 patients were included in the study. T2DM was diagnosed in 7.2%. The sensitivities for detecting T2DM were 33.3%, 61.1% and 77.8% during admission and 27.8%, 61.1% and 72.2% at follow-up for HbA1c, FPG and 2hPG, respectively. The positive predictive values (PPVs) for diagnosing T2DM were 100%, 91.7% and 51.9% during admission and 71.4%, 91.7% and 65.0% at follow-up for HbA1c, FPG and 2hPG, respectively. The specificities and negative predictive values were high for all methods. By combining all measurements, the sensitivity was 100% and the PPV was 44.2%, while the combination of all HbA1c and FPG measurements provided 88.9% sensitivity and 80.0% PPV.
Conclusion: Diagnosis of T2DM can be reliably carried out by repeated measurements of FPG and HbA1c in ACS patients, with limited added value of an oral glucose tolerance test.
Keywords: Type 2 diabetes; acute coronary syndrome; cardiovascular disease(s); diagnosis; prediabetes.