Absence of Obesity Paradox in Morbidly Obese Patients Listed for Heart Transplantation in Contemporary Era

Abstract

<h3>Purpose</h3> Post heart transplant (HT) outcome of patients with body mass index ≥ 35 kg/m² (morbidly obese) remain suboptimal. However, outcome of morbidly obese patients listed for heart transplant (HT) is unknown. We sought to examine the characteristic and outcome of such patients who were listed for HT in the United States. <h3>Methods</h3> Adults listed for HT with BMI information on the Scientific Registry of Transplant Recipients database between 2000 and 2018 were included. Characteristics and outcomes of patients with BMI≥ 35 kg/m² or = 18.5-34.99 kg/m² were compared. The patients were followed until death, transplant or end of data availability. Waitlist mortality and successful HT were compared between groups using a Fine and Gray competing risk hazard regression model adjusted for known risk factors. <h3>Results</h3> 55,717 patients identified: 5022 (9.0%) had a BMI ≥ 35 kg/m²; 13,058 (23.4%) were female. The median (25^th, 75^th percentile) age was 55 (45, 61) years, and the median waitlist time was 101 (27, 299) days. Morbidly obese patients were significantly younger (51 vs. 55 years; p<0.0001), had higher hypertension (57.9% vs. 48.3%; p<0.0001), diabetes (41.1% vs. 26.4%; p<0.0001), and LVAD use (25.9% vs. 17.5%; p<0.0001). Annual listing of morbidly obese patients significantly increased after 2008 (from 200 before 2008 to nearly 400 in 2017, p_Trend<0.0001). The waitlist mortality (sub-hazard ratio [SHR] 1.40, 95% confidence interval [CI] 1.27-1.53) and likelihood of receiving HT (SHR 0.76, 95% CI 0.73-0.80) were significantly lower for those with a BMI≥ 35 kg/m². <h3>Conclusion</h3> Listing of patients with BMI≥ 35 kg/m² is on rise. However, this cohort is at significantly higher risk for death and lower HT rates.