Is recipient's body mass index a determinant of short term complications in early renal transplantation?

OBJECTIVES Obesity prevalence has increased over the past 20 years in the general population and among kidney transplant recipients. General surgical belief is that obesity increases surgical difficulty. The aim of this study was to assess the impact of Body Mass Index (BMI) on perioperative complications. METHODS All kidney transplantations performed in adults in our centre from 2006 to 2011 were analysed. Data on patients' characteristics, surgical protocol, intra and postoperative complications and renal function were collected. Patients were divided into 4 groups as follows: underweight (BMI<18.5kg/m2), normal weight (18.5kg/m2≤BMI<25kg/m2), overweight (25kg/m2≤BMI<30kg/m2) and obese (BMI≥30kg/m2). We also studied the impact of BMI on complications using it as a continuous variable to identify potential threshold values. RESULTS Among 694 patients included, 52% had normal BMI, 7%, 31% and 9% were underweight, overweight and obese, respectively. In multivariate analysis, overweight was significantly associated with longer operative time compared to normal-weight patients (estimated mean difference of 10,4min, 95% confidence interval (CI) [4.0; 16.9]) and obesity was associated with an increased risk of wound dehiscence (odds ratio 3.1, 95%CI [1.3; 7.3] compared with normal-weight patients). Considering BMI as a continuous variable, the risk of parietal dehiscence significantly increased beyond a BMI of 26kg/m2, intraoperative blood loss and the risk of ureteral stenosis beyond 32kg/m2 and the risk of abdominal wall hematoma beyond a BMI of 34kg/m2. CONCLUSIONS We found BMI thresholds above which intraoperative blood loss and the risk of parietal dehiscence, ureteral stenosis, and parietal hematoma significantly increased. LEVEL OF EVIDENCE 3.