No benefit from the obesity paradox for diabetic patients with heart failure.

Abstract

Paradoxically, obesity is associated with survival in heart failure (HF). Whether this is true for HF patients with comorbid type-2 diabetes (T2D) remains uncertain. Our aim was to address this issue in diabetic patients by collecting correlates for body mass index (BMI) and long-term mortality. Both BMI and survival after a mean follow-up of 4.3 ± 3.0 years (up to 10 years) were assessed for 2527 ambulatory patients (66.3% men; mean age 69 ± 12.3 years). A total of 1102 (43.6%) patients had T2D and ischaemic aetiology of HF was present in 47.8%; mean left ventricular ejection fraction was 38 ± 16%. Based on BMI scores, patients were categorized as either underweight, normal, overweight, or obese. A significant survival interaction was observed between BMI and T2D. Smooth spline curves for the estimation of risk of all-cause and cardiovascular death showed the classic obesity paradox, with reduced mortality as BMI increased in non-diabetics; for T2D patients this pattern was lost. After adjustment for age and sex, hazard ratios for low-weight and obesity were: 2.04 [95% confidence intervals (CI) 1.50-2.78, P < 0.001] and 0.76 (95% CI 0.58-0.99, P = 0.04), respectively, for non-T2D patients; and 1.30 (95% CI 0.77-2.19, P = 0.32) and 0.99 (95% CI 0.78-1.26, P = 0.95), respectively, for T2D patients. Multivariate analyses for mortality (including BMI as a continuous variable) were significant for non-diabetic patients only. In patients with HF, but without T2D, the obesity paradox was present; however, T2D removed this phenomenon. Advice about weight loss for obese diabetic patients with HF requires further research.