Obesity Leads to Increased Mortality in Pediatric Heart Transplant Recipients - A Pediatric Heart Transplant Society Study

Abstract

The obesity epidemic has afflicted children of all ages with heart transplant (HT) recipients at significant risk compared to their pediatric counterpart. This study is the first large scale study to evaluate the prevalence of obesity in pediatric HT recipients and its effects on cardiac allograft vasculopathy (CAV) and graft survival. We evaluated pediatric HT recipients (age < 20 years) transplanted between 01/1996-09/2018 from the Pediatric Heart Transplant Society (PHTS) database, a prospective multi-center database for pediatric HT institutions. Obesity was defined as body mass index (BMI) ≥95th %ile (CDC guidelines; age >2 years) and weight/length z score >95%ile (WHO guidelines; age <2 years). Freedom from CAV development and graft loss were analyzed based on anthropometric measures at transplant for BMI. Cox proportional hazards regression model was utilized to identify risk factors for both CAV development and graft loss. 4756 pediatric HT patients (pts) met study criteria (mean age at 1 year post-HT = 6.7 ± 6.2 yrs; 44.6% female; 69.5% White). At HT, 56% had a normal weight, 10% were overweight, 11% were obese and 23% were underweight. Overall, ∼60% had normal BMI that remained consistent up to 15 years post-HT (56-69%). For obese pts at HT, there was an increased risk for CAV development (HR 1.5, p = 0.002) and graft loss (HR 1.3, p = 0.001), see Figure. The risk of CAV development remained significant for obese pts at 5 years post-HT (p <0.001). Only 60% of pediatric HT recipients had ideal BMI at 1 year and 5 year follow up. Obesity at HT predicts an increased risk of CAV and graft loss. Exploring metabolic risk factors that lead to CAV development and graft loss are important. Healthy lifestyle interventions pre-HT and during HT follow up may potentially reduce morbidity and mortality.