Impact of different immunosuppressive protocols on clinical outcomes in obese kidney transplant recipients: a propensity score-matched analysis

Background. Although obesity has become a significant problem in transplantation medicine, the impact of different immunosuppressive protocols on clinical outcomes in obese transplant recipients remains unclear. Methods. We performed an analysis of the Scientific Registry of Transplant Recipients database. Kidney transplant recipients were categorized according to body mass index (BMI) categories and immunosuppressive protocols: (i) tacrolimus/mycophenolate mofetil (Tac-MMF), (ii) mTOR-inhibitor/Tac (mTORi-Tac), (iii) mTORi/cyclosporin (mTORi-Cyc) and (iv) mTORi-MMF. Results. Graft recipients with advanced obesity (BMI >= 35 kg/m(2)) exhibited significantly lower rates of acute rejection during the first year after transplantation in the mTORi-Tac (6.4%) group compared with Tac-MMF (11.2%). Obesity class 1 (30 < BMI< 35 kg/m(2)) was associatedwith a significant risk of acute rejection for the mTORi-Tac group [obesity class 1 hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.212.62, P =.003]. A similar trend was observed in the TacMMF group for advanced obesity HR 1.29; 95% CI 0.961.73, P =.087). For the Tac-MMF group, recipients with both overweight and obesity had significantly impaired survival due to cardiovascular events and also increased mortality due to infection in advanced obesity. Combination of mTORi and calcineurin inhibitor was associated with lower rejection rates and stable long-term kidney function while reducing cardiovascular side effects linked to calcineurin inhibitors in obese kidney graft recipients. Conclusion. These results are critical for the growing number of obese graft recipients and warrant prospective evaluation.