Increased estimated fat-free mass and fat mass associated with improved clinical outcome in heart failure

Background Increased weight measured by body mass index is associated with better clinical outcomes in heart failure (HF). The effect of specific components of body mass on outcome is limited. We evaluated the impact of fat-free mass and fat mass on mortality and cardiovascular hospitalization in a large real-world cohort of patients with chronic HF. Methods Body measurements were assessed in patients with chronic HF. Fat-free mass, fat mass and waist circumference were calculated based on specifically derived formulas. Results The cohort included 6328 HF patients. Mean follow-up was 744 days. Increased body composition indices including body mass index, fat-free mass index and fat mass index, per cent body fat and waist circumference were associated with better survival. Cox regression analysis after adjustment for other significant parameters demonstrated that these indices were all associated with improved survival. The strongest association was seen with fat-free mass index with a graded increase in survival; lowest death in the highest quartile compared to reference second quartile (hazard ratio 0.79, 95% confidence interval 0.67-0.93, P < .01). There was no interaction with sex or HF type. Analysis of the clinical outcome of death and cardiovascular hospitalization demonstrated that a worse prognosis was in the lowest quartile of all the indices. A sensitivity analysis, analysing these indices as continuous parameters using restricted cubic splines, demonstrated a clear continuous association between these indices and increased survival in both sexes. Conclusions Body mass including fat-free mass and fat mass was associated with improved survival in patients with HF.