Impact of pretransplant recipient body mass index on post heart transplant mortality: A systematic review and meta-analysis.

The ISHLT's 2016 Guidelines on the selection of heart transplant (HT) candidates recommends weight loss prior to listing for persons with body mass (BMI) index greater than 35 kg/m2 . We conducted a systematic review to assess the impact of BMI on all-cause mortality. We searched to identify eligible observational studies that followed HT recipients. We used the GRADE system to quantify absolute effects and quality of evidence, and meta-analyzed survival curves to assess post-transplant mortality across BMI categories. We found a significantly increased risk of mortality in patients with BMI > 30 kg/m2 across all age categories, independently of transplant era and study source (BMI 30-34.9: HR 1.10, 95% CI 1.04-1.17; BMI ≥ 35: HR 1.24, 95% CI 1.12-1.38). We also found an increased risk of death in underweight (BMI < 18.5 kg/m2 ) candidates over 39 years of age (Age 40-65: HR 1.24, 95% CI 1.02-1.53; Age > 65: HR 1.70, 95% 1.13-2.57). We found obesity and underweight BMI to be associated with mortality post-HT. The similar and overlapping increased risk of mortality in patients with BMI 30-34.9 and BMI ≥ 35 does not support the recently updated ISHLT guidelines. Future evidence in the form of randomized controlled trials is required to assess effectiveness of interventions targeting obesity-related comorbidities and weight management.