Clinical Significance of Mycophenolate Mofetil Withdrawal in Kidney Transplant Recipients

Introduction. The most effective immunosuppressant protocol in kidney transplantation (KT) is the combination of a calcineurin inhibitor, steroid, and mycophenolate mofetil (MMF) until now. However, MMF withdrawal (MW) is performed for many reasons, and the clinical course of the KT recipients after MW is not clearly known. The purpose of this study was to investigate the clinical outcomes of KT after MW. Materials and Methods. We retrospectively analyzed the medical records of 626 KT recipients between 2000 and 2016. We evaluated the incidence of biopsy-proven acute rejection (BPAR), graft and patient survival rates, and risk factors related with graft failure. Results. The proportion of MW was 33.2% (208 of 626 patients). The median time between KT and MW was 6.4 months (range, 3.2-32.1 months). The common causes of MW were infection (70.7%), hematologic abnormalities (9.1%), and gastrointestinal trouble (7.7%). The incidence of BPAR was significantly higher in the MW group compared with the MMF continuation group (27.4% vs 8.9%, respectively, P < .001). Death-censored graft survival and patient survival rates were significantly lower in the MW group compared with the MMF continuation group (P < .001; P < .001, respectively). In the multivariate analysis, BPAR after MW was an independent risk factor for graft failure (hazard ratio 6.058, 95% confidence interval, 3.172-11.569, P < .001). Conclusions. The incidence of rejection, graft failure, and patient mortality in KT were high after MW. Therefore, MW should be considered carefully.