Reporting of rejection after renal transplantation in large immunosuppressive trials: Biopsy-proven, clinical, presumed, or treated rejection?

Background. Prevention of acute rejection still is all important endpoint in randomized controlled trials. Poor study reporting may create confusion and render decision-snaking difficult. The present study thoroughly analyses the presentation and definition of rejection in reports on large multicenter immunosuppressive trials published in the field of renal transplantation. Methods. Publications of large immunosuppression trials in kidney transplantation were identified by a predefined search strategy. The reported acute and biopsy-proven acute rejection (BPAR) episodes and additional information oil number of patients recruited, publication year, impact factor, definition of acute rejection and the reporting of efficacy analyses were extracted. All reports were scanned for (a) at what point and (b) for which signs or reasons a biopsy was performed. Results. Eight of 41 (19.5%) papers investigating rejection rates reported a sufficient definition of acute rejection. Twenty-eight of 41 (68.3%) presented more than one rejection rate and were published in significantly higher impact journals. The absolute difference between clinical rejection and BPAR had a median of 6.5% and a wide range (0-16.9 %). Efficacy analysis was presented in all but four (90.2%) reports. Thirteen of 35 (37.1%) papers did report the timing of the biopsies and 25 of 35 (71.4%) publications gave specifications of when a biopsy sample should be taken. Conclusions. The requirements of proper reporting of rejection episodes are not fulfilled in most of the publications and the use of many different terms for the description of rejection rates is confusing at present. Our comprehensive review clearly demonstrates the need for improved and standardized reporting of rejection episodes and we suggest to report both acute rejection and BPAR.