Impact of adiposity on clinical outcomes in people living with a Fontan circulation.

BACKGROUND

To assess the association between body composition and the risk of adverse outcomes in Fontan patients.

METHODS

Participants from the Australian and New Zealand Fontan Registry with dual-energy X-ray absorptiometry scans were included. Appendicular lean mass (ALM), appendicular lean mass index (ALM divided by height squared; ALMI) and total body fat mass percentage (%BF) were calculated. ALMI and %BF z-scores were derived using age- and sex-matched reference ranges. The primary outcome was Fontan failure (death, transplantation, New York Heart Association functional class III/IV, protein-losing enteropathy, and plastic bronchitis) or moderate-or-severe ventricular dysfunction.

RESULTS

144 patients were included. Mean %BF was 29% (SD 10) with 50% having increased adiposity. Mean ALMI z-score was -1.4 (SD 1.1); one third of patients had skeletal muscle deficiency (ALMI z-score < -1 and -2) and another third had Fontan-associated myopaenia (ALMI z-score < -2). Age and %BF were associated with the risk of the endpoint in univariable regression (age: HR 1.09 per year, 95% CI 1.02-1.17, p = 0.01; %BF: HR 1.08, 95% CI 1.01-1.17, p = 0.03). On multivariable regression, every 1% increase in %BF was associated with a 10% increased risk of reaching the clinical endpoint (HR 1.10, 95% CI 1.01-1.19; p = 0.03). ALM was not associated with the endpoint (HR 1.02 per kg, 95% CI 0.88-1.20, p = 0.77).

CONCLUSIONS

Increased adiposity is associated with higher risk for adverse outcomes. Prospective studies to assess lifestyle interventions to optimise body composition should be prioritised.