Association between history of bariatric surgery and graft rejection among solid organ transplant recipients

Objective: We sought to assess the potential association between history of bariatric surgery and graft rejection among solid organ transplant (SOT) recipients. Methods: We conducted a single-center retrospective study of adult (age ≥18 years) SOT recipients (2000-2015) at a large tertiary care transplant network with graft rejection and bariatric surgery history according to the international classification of diseases 9^th revision. Data were analyzed using ANOVA, Chi Square, Fisher Exact tests, and logistic regression. Results: Of 4363 SOT recipients, 72.6% had a history of graft rejection and 55 (1.3%) had a history of bariatric surgery. On univariate analysis, patients with graft rejection were more likely to have a history of bariatric surgery than those without organ rejection (1.5% vs. 0.7%, p=0.015). In multivariable analysis adjusted for age, transplant organ type, and history of calcineurin-based immunosuppression, there was increased odds of rejection among those with a history of bariatric surgery (Odds Ratio (OR): 3.01, 95% Confidence Interval (CI):0.98-4.46, p=0.05). However, when adjusted for body mass index at transplant, the association was attenuated (OR:3.48, CI:0.81-14.9, p=0.10). Conclusion: Our single-center data indicate that the relationship between a history of bariatric surgery and graft rejection after SOT may be explained by obesity.