Diagnostic and Prognostic Value of the Electrocardiogram in Stable Outpatients With Type 2 Diabetes

Background: The 2019 European Society of Cardiology (ESC) guidelines on diabetes and cardiovascular disease (CVD) recommend an electrocardiogram (ECG) in patients with diabetes and hypertension or with suspected CVD, including heart failure (HF). The objective was to investigate whether ECG abnormalities can be used as a diagnostic and prognostic marker of HF in patients with type-2 diabetes (T2D) in secondary care diabetes-clinics. Methods: A total of 722 patients with T2D in sinus rhythm were prospectively included. The ESC definition of HF with reduced and preserved ejection fraction (HFrEF and HFpEF) was used. An abnormal ECG was defined as having Q-waves, bundle-branch-block, left ventricular hypertrophy, or ST-T deviations. The composite endpoint was incident CVD and cardiovascular death.Results: Overall, 24% patients had ECG abnormalities. A total of 13% had HF (2.5% HFrEF and 11% HFpEF) whereof 51% had ECG abnormalities. A normal ECG had a 99.2% negative predictive value (NPV) of ruling out HFrEF. The ECG was less efficient in ruling out HFpEF (NPV of 92%). In a multivariable analysis, the hazard-ratio (HR) of incident cardiovascular disease or death in patients with HFrEF or HFpEF and a normal ECG compared to patients without HF was 1.88 [1.00-3.53], p=0.05, while an abnormal ECG increased the HR to 3.62 [2.18-6.00], p<0.001.Conclusion: HFrEF was rare and HFpEF was frequent in this T2D population. A normal ECG could safely rule out HFrEF but not HFpEF. The ECG carried prognostic information and an abnormal ECG increased the HR for incident cardiovascular event or cardiovascular death.