Body composition and survival in stable coronary heart disease: impact of lean mass index and body fat in the "obesity paradox".

Objectives: Our goal was to determine the impact of lean mass index (LMI) and body fat (BF) on survival in patients with coronary heart disease (CHD).

Background: An inverse relationship between obesity and prognosis has been demonstrated (the "obesity paradox") in CHD, which has been explained by limitations in the use of body mass index in defining body composition.

Methods: We studied 570 consecutive patients with CHD who were referred to cardiac rehabilitation, stratified as Low (≤25% in men and ≤35% in women) and High (>25% in men and >35% in women) BF and as Low (≤18.9 kg/m2 in men and ≤15.4 kg/m2 in women) and High LMI, and followed for 3 years for survival.

Results: Mortality is inversely related to LMI (p<0.0001). Mortality was highest in the Low BF/Low LMI group (15%), which was significantly higher than in the other 3 groups, and lowest in the High BF/High LMI group (2.2%), which was significantly lower than in the other 3 groups. In Cox regression analysis as categoric variables, low LMI (hazard ratio [HR]: 3.1; 95% confidence interval [CI]: 1.3 to 7.1) and low BF (HR: 2.6; 95% CI: 1.1 to 6.4) predicted higher mortality, and as continuous variables, high BF (HR: 0.91; 95% CI: 0.85 to 0.97) and high LMI (HR: 0.81; 95% CI: 0.65 to 1.00) predicted lower mortality.

Conclusions: In patients with stable CHD, both LMI and BF predict mortality, with mortality particularly high in those with Low LMI/Low BF and lowest in those with High LMI/High BF. Determination of optimal body composition in primary and secondary CHD prevention is needed.