Impact of waitlist weight change on outcomes in heart transplant recipients: a UNOS database analysis

Background While the effect of pre-transplant weight on patient outcomes following heart transplantation (HTx) has previously been studied, data regarding the impact of dynamic weight change prior to HTx are extremely limited. Objectives We sought to elucidate the interaction between HTx listing weight and weight change while waitlisted, and explore how that interaction impacts post-HTx survival in a continuous manner. Methods Adult patients listed for HTx from 1987 to 2020 were identified from UNOS database. Three-dimensional restricted cubic spline analysis explored post-HTx survival relative to both changes in BMI/weight and BMI at time of HTx listing. Continuous predictor variables were analyzed with Cox proportional hazards method. Results 9,628 included patients underwent HTx. Median recipient age was 55 [IQR 46-62] years, and 21% were females. 53% of patients lost while 47% gained weight on the waitlist. Median BMI (27.6 kg/m(2) [24.3-31.3] vs. 27.4 kg/m(2) [24.2-30.9], paired p < 0.001) and weight (84.8 kg [73.0-98.0] kg vs. 84.4 kg [72.6-96.6], p < 0.001) were similar at listing and transplant. One-year survival was 89.3%. Weight loss over 3 BMI points or 10 kg was associated with higher hazard of death irrespective of listing BMI. In non-obese patients, some weight gain (1-4 BMI points or 5-15 kg) was associated with improved survival. In cachectic patients (BMI < 18.5), failure to gain weight was associated with worse survival. Conclusions Impact of weight change varies depending on listing BMI. While a survival benefit is seen in non-obese patients who gain some weight, significant weight loss is associated with poorer survival.