Outcomes of Heart Transplant Recipients with Class II Obesity: A United Network for Organ Sharing Database Analysis

Background: In the 2016 ISHLT listing criteria guidelines for heart transplantation, recipients were recommended to have a body mass index (BMI) <35 kg/m². However, outcomes data for subgroups of transplant recipients with a BMI >35 kg/m² are limited. We examined the outcomes of heart transplant recipients who had a BMI of 35 to 39.9 kg/m² or ≥40 kg/m² and compared their outcomes with recipients who had a BMI <35 kg/m².

Methods: Using data from the United Network for Organ Sharing database, we performed a retrospective cohort analysis of 23,009 adults who underwent cardiac transplantation between 2009 and 2018. Transplant recipients were stratified by BMI categories (<35 kg/m², 35-39.9 kg/m², and ≥40 kg/m²). Patient survival was depicted by Kaplan-Meier curves. Cox proportional-hazards modeling was used to determine the prognostic factors associated with mortality within 90 days, 1 year, and 5 years after transplantation.

Results: Survival at 90 days, 1 year, and 5 years after transplantation was better in recipients who had a BMI <35 kg/m² than in those who had a BMI of 35 to 39.9 kg/m² (P values ranged from 0.01 to < 0.001) or ≥40 kg/m² (P < 0.001). Additionally, survival at 90 days (P < 0.001) and 1 year (P = 0.002) was significantly better in recipients who had a BMI of 35 to 39.9 kg/m² than in those who had a BMI ≥40 kg/m². In multivariate analysis, a BMI of 35 to 39.9 was significantly associated with increased 90-day mortality (HR = 1.53; 95% CI 1.12, 2.08; P = 0.01) but not increased 1-year (HR = 1.28; 95% CI 0.99, 1.66; P = 0.06) or 5-year mortality (HR = 1.11; 95% CI 0.91, 1.36; P = 0.29).

Conclusions: Although heart transplant recipients with class II obesity (BMI 35-39.9 kg/m²) may have suboptimal survival compared with those who have a BMI <35 kg/m², these patients have better outcomes than do those with class III obesity (BMI ≥40 kg/m²). Thus, contrary to current guidelines, selected patients with class II obesity should be considered for transplantation.