Body mass index is an independent predictor of Clavien-Dindo grade 3 complications in patients undergoing robot assisted radical prostatectomy with extensive pelvic lymph node dissection.

Robot assisted radical prostatectomy (RARP) with extensive pelvic lymph node dissection (ePLND) is an effective procedure for treating and staging prostate cancer; however, high grade complications represent a critical issue. To investigate clinical factors associated with the risk of Clavien-Dindo grade 3 complications in patients undergoing RARP with ePLND. The study included 211 consecutive patients who were operated in a period running from June 2013 to March 2017. Factors associated with grade 3 complications were evaluated by the logistic regression model. Receiver operating characteristic curves and area under the curve (AUC) were used to assess the risk model. Of the 211 patients included in the study, 55 (26.1%) had complications, which were classified Clavien grade one in 36 cases (17.1%), two in 7 (3.3%), 3a in 9 (4.3%) and 3b in 3 (1.4%). Higher median measurements of body mass index (BMI) were detected in grade 3 subjects (27.6 kg/m2) when compared to grade 0-2 cases (25 kg/m2) and the difference was significant (P = 0.015). BMI increased the risk of high grade complications (odds ratio, OR 1.184; P = 0.047) with a fair discrimination power (AUC 0.709). It generated a risk curve by the model, which stratified patients in low (BMI < 26 kg/m2; probability risk less than 5%), intermediate (26 ≤ BMI (kg/m2) ≤ 30; risk between 5 and 10%), and high (BMI > 30 kg/m2; risk between 10 and 20%) risk classes for grade 3 complications. BMI is an independent predictor of grade 3 complications, which are increased by 18.4% for each unit rise. Patients may be stratified preoperatively by BMI into grade 3 risk categories, which include low (normal weight), intermediate (overweight), and high (obese) risk cases.