Rapid Weight Change Following Heart Transplantation is Associated with Adverse Outcomes: An Analysis of the ISHLT Transplant Registry

Abstract

<h3>Purpose</h3> Substantial total body weight (TBW) gain is frequently observed after heart transplant (HT), but little is known about the effect of the rate of weight change on outcomes. We assessed the pattern of post-HT change in TBW and its impact on outcomes. <h3>Methods</h3> Post-HT changes in TBW, fat mass (FM) and fat-free mass (FFM) were examined for 15,182 adult recipients in the ISHLT Registry transplanted between 1996 and 2016 who survived to 1 year and for whom serial body weight data were recorded. Patients were stratified into quartiles of 1-year TBW percent change. Endpoints included treated rejection (TR), cardiac allograft vasculopathy (CAV), and all-cause mortality. <h3>Results</h3> TBW gain was seen in a large number of patients after HT, such that the proportion of obese patients increased from 21% at HT to 30% at 1 year after HT (<i>p</i> <0.05). FM, rather than FFM, was responsible for most of the TBW change (Figure 1A). Lower freedom from CAV, TR, and higher mortality were seen in patients in the upper quartile of TBW change in unadjusted survival analyses (Figure 1B-D) and after adjustment in multivariable analysis - HR=1.37, p<0.001 for TR, HR=1.24, p<0.001 for CAV and HR=1.15, p=0.02 for mortality. Gain in FM was predominantly responsible for the increased risk, and this risk associated with weight gain was independent of absolute weight attained. <h3>Conclusion</h3> A large proportion of HT recipients are at risk of weight gain. Significant weight gain in the first year after transplant is associated with a risk of adverse outcomes, independent of absolute weight or BMI. Mitigation of the rate of weight gain, and especially the FM contribution to weight gain, could reduce post-transplant morbidity and mortality.