Impact of Prediabetes on Cardiac Function Among Primary Care Patients

Background: Prediabetes is a novel risk factor recently associated with changes in the left ventricle. Our aim is to determine if prediabetes is associated with heart failure (HF) and structural heart disease. Methods: We conducted a cross-sectional study and performed screening echocardiograms to consecutive primary care patients. We calculated the hemoglobin A1c (HbA1c) within 3 months of the echocardiogram and classified patients as having normal glucose, low-risk or high-risk prediabetes or diabetes. Our primary outcome was HF defined as an ejection fraction (EF) <50% and HF with preserved EF. Our secondary outcome was structural heart disease defined as having either a large atrium, left ventricular hypertrophy, or low EF. Results: We included 15,056 patients who underwent a screening echocardiogram and had a recorded HbA1c. Only 2794 patients had a normal blood glucose, 4201 had low-risk prediabetes, 2499 had high-risk prediabetes, and the remainder had diabetes. The adjusted odds ratio (ORs) of HF for low-risk prediabetes, high-risk prediabetes and diabetes were 1.38 [confidence interval (95% CI) 1.07-1.78] (P = 0.01), 1.47 (95% CI 1.05-2.01) (P = 0.01), and 1.60 (95% CI 1.16-2.01) (P < 0.01), respectively, when compared with normoglycemic patients. The adjusted OR of HF with preserved EF for low- and high-risk prediabetes and diabetes were 1.17 (95% CI 0.86-1.60) (P = 0.30), 1.60 (95% CI 1.15-2.21) (P < 0.01), and 1.63 (95% CI 1.24-2.13) (P < 0.01), respectively, when compared with normoglycemic patients. Conclusions: Prediabetes is a prevalent condition associated with structural heart disease and HF.