Cardiovascular Phenotype in HFpEF Patients With or Without Diabetes

Background: RELAX was a multicenter randomized trial of sildenafil versus placebo in heart failure and preserved ejection fraction (HFpEF) with rigorous entry criteria and extensive phenotypic characterization of participants. Objectives: To characterize clinical features, exercise capacity, and outcomes in patients with HFpEF with or without diabetes and gain insight into contributing pathophysiologic mechanisms. Methods: RELAX enrolled 216 stable outpatients with heart failure, EF ≥50%, elevated natriuretic peptide or intracardiac pressures, and reduced exercise capacity. Prospectively collected data included echocardiography, cardiac magnetic resonance imaging, a comprehensive biomarker panel, exercise testing, and clinical events over 6 months. Results: Compared with non-diabetics (n=123), diabetic (n=93) HFpEF patients were younger, more obese, more often male, and had a higher prevalence of hypertension, renal dysfunction, pulmonary disease, and vascular disease (p<0.05 for all). Uric acid, C-reactive protein, galectin-3, carboxy-terminal telopeptide of collagen type I, and endothelin-1 levels were higher in diabetics (p<0.05 for all). Diabetic patients had more ventricular hypertrophy but systolic and diastolic ventricular function parameters were similar in diabetics and non-diabetics except for a trend toward higher filling pressures (E/e′) in diabetics. Diabetics had worse maximal (peak oxygen uptake) and submaximal (6-minute walk distance) exercise capacity (p<0.01 for both). Diabetic patients were more likely to have been hospitalized for HF in the year prior to study entry (47% vs 28%, p=0.004) and had a higher incidence of cardiac or renal hospitalization at 6 months after enrollment (23.7% vs 4.9%, p<0.001). Conclusions: HFpEF patients with diabetes are at increased risk of hospitalization and have reduced exercise capacity. Multi-morbidity, impaired chronotropic reserve, left ventricular hypertrophy and activation of inflammatory, pro-oxidative, vasoconstrictor, and pro-fibrotic pathways may contribute to adverse outcomes in HFpEF patients with diabetes. ( NCT00763867 )