Introduction and objectives: The predictive value of ECG abnormalities in patients with type-2 diabetes mellitus (DM2) has not been fully studied. Our objective was to assess the prognostic value of ECG abnormalities in patients with DM2 but without known cardiovascular disease.
Methods: Overall, 412 patients with DM2 were identified at two primary care centers in the same city. Two hundred and twenty one patients younger 80 years without known cardiovascular disease were included in the study. An ECG was recorded at baseline and annually during follow-up. The ECGs were evaluated using a system based on the Minnesota code. The main study end-point during follow-up was the occurrence of a cardiovascular event, as defined in the Framingham study.
Results: The mean follow-up duration was 5.9 years (1.1-8.5 years). At the beginning of the study, 24.9% of patients had ECG abnormalities; at the end, 44.3% had abnormalities. Cardiovascular events occurred in 65 patients (29.4%). The relative risk (RR) of a cardiovascular event in a patient with an ECG abnormality was 8.28 (95% confidence interval [CI], 3.36-20.42). Only hypertension (RR = 2.29; 95% CI, 1.24-4.22) and age were significantly related to the occurrence of a cardiovascular event. Multiple regression analysis that included classical risk factors and ECG findings showed that an ECG abnormality was a significant independent predictor, with adjusted RR = 5.95 (95% CI, 2.29-15.47).
Conclusions: The presence of an ECG abnormality can predict the occurrence of a future cardiovascular event in patients with DM2 more accurately than risk factors alone. This finding could be helpful in selecting subgroups of high-risk diabetic patients.