High prevalence of undiagnosed abnormal glucose tolerance in patients with acute myocardial infarction in Northern Sweden

Background and Aim Abnormal glucose tolerance is frequent in patients presenting with acute myocardial infarction (AMI) and is associated with adverse prognosis. However, contemporary data from Northern Sweden are limited. Aim To determine the prevalence and patterns of dysglycemia in AMI patients in Northern Sweden and to identify clinical associates of abnormal glucose regulation. Methods In this prospective study we evaluated 130 patients admitted with AMI. Glucose metabolism was assessed using fasting glucose, HbA1c, and an oral glucose tolerance test (OGTT). Patients were classified as normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT), newly diagnosed diabetes mellitus (NDM), or known diabetes mellitus (KDM). Clinical characteristics and cardiovascular risk factors were compared between groups. Logistic regression was performed to identify predictors of dysglycemia. Results The mean age (SD) of the cohort was 65.2 (9.4) years, and 19.7% were women. Overall, 55.4% had abnormal glucose tolerance: 17.7% KDM, 11.5% NDM, 8.5% IFG, and 17.7% IGT. Compared with NGT, patients with dysglycemia more frequently had hypertension (65 vs. 40%, p = 0.005) and hyperlipidaemia (47 vs. 24%, p=0.005). Patients with KDM had higher HbA1c (60 (16) vs. 42 (5) mmol/mol, p<0.001) and fasting glucose [7.8 (2.1) vs. 6.2 (1.3)], p=0.004 mmol/L), but lower total cholesterol [4.1 (1.0) vs. 4.9 (1.4)] mmol/L, p=0.024) and low-density lipoprotein cholesterol [2.1 (0.8) vs. 3.0 (1.3) mmol/L, p=0.005], compared to AMI patients with NDM or IFG or IGT. In multivariable logistic regression analysis, arterial hypertension independently associated with dysglycemia [adjusted OR 2.34 (1.08-5.06), p=0.031]. Conclusions More than half of patients admitted with AMI in Northern Sweden had abnormal glucose tolerance, most of which were previously unrecognized. These findings confirm and extend earlier studies and highlight the need for systematic detection and management of dysglycemia as part of comprehensive AMI care. Routine incorporation of HbA1c and an oral OGTT into the evaluation of AMI patients should be considered to enhance risk stratification and optimize long-term outcomes. Furthermore, we show that hypertension and abnormal glucose tolerance cluster and, in the work-up after an acute cardiovascular event, all known and modifiable risk factors should be screened for.