Does obesity paradox exist for patients with heart failure?

Takeaway

• Both for heart failure patients with left ventricular preserved ejection fraction (HFpEF) and reduced ejection fraction (HFrEF), the associations between BMI and mortality are U-shaped (very low body weight and extreme obesity are both dangerous) with a similar nadir of risk at a BMI of 32-33 kg/m².
• It is unknown whether interventions to change BMI alter the risk.

Why this matters

• Previous studies have shown an inverse and U-shaped association between obesity and mortality in patients with heart failure with a nadir between 30 and 42 kg/m². 

Study design

• Meta-analysis of 10 studies (n=96,424) identified after a search across electronic database.
• Study evaluated associations between BMI and all-cause mortality in patients with HFrEF (n=59,263; mean age 68 years) or HFpEF (n=37,161; mean age 60 years).
• Funding: None disclosed.

Key results

• After adjustment for confounders, risk for all-cause mortality per 5 units increase in BMI was similar in patients with HFpEF (HR, 0.93; 95% CI, 0.89-0.97) and HFrEF (HR, 0.96; 95% CI, 0.92-0.99).
• The dose–response meta-analysis showed:
  • U-shaped association between BMI and all-cause mortality in patients with HFpEF with the nadir of risk at a BMI of 32-33 kg/m² (P­_nonlinearity<.01).
  • Flatter U-shaped association between BMI and all-cause mortality in patients with HFrEF with the nadir of risk at a BMI of 33 kg/m² (P<.01).

Limitations

• Patients with LVEF of 40%-49% could have been misclassified as either HFpEF or HFrEF.
• Meta-analysis only included studies with more than 2 BMI categories.