Patient factors predict complications after partial nephrectomy: Validation and calibration of the PREP (Preoperative Risk Evaluation for Partial Nephrectomy) score.

To develop and validate the PREP (Preoperative Risk Evaluation for Partial Nephrectomy) score to predict the probability of major postoperative complications following partial nephrectomy (PN) based on patient comorbidities.

The Premier Healthcare Database was used to identify patients who had undergone elective PN. Through review of ICD-9 codes, we identified patient comorbidities and major surgical complications (Clavien grade 3-5). Multivariable logistic regression was used to identify predictors of major complications. We used half of the set as the training cohort to develop our risk score and the other half as a validation cohort.

From 2003-2015, 25,451 PN were performed. The overall rate of major complications was 4.9%. The final risk score consisted of 10 predictors: age, sex, CHF, CAD, COPD, CKD, diabetes, hypertension, obesity, smoking. In the training cohort, the area under the receiver-operator characteristic curve (AUC) was 0.75 (95% CI 0.73-0.78), while the AUC for the validation cohort was 0.73 (95% CI 0.70-0.75). The predicted probabilities of major complication in the low risk (≤10 points), intermediate risk (11-20 points), high risk (21-30 points), and very high risk (>30 points) categories were 3% (95% CI 2.6-3.2), 8% (95% CI 7.2-9.2), 24% (95% CI 20.5-27.8), and 41% (95% CI 34.5-47.8) respectively.

We developed and validated the PREP score to predict the risk of complications following PN based on patient characteristics. Calculation of the PREP score can help providers select treatment options for patients with a cT1a renal mass and enhance the informed consent process for patients planning to undergo PN.

BJU international. 2020 Sep 12 [Epub ahead of print]

Melissa J Huynh, Ye Wang, Mugdha Joshi, Ross Krasnow, Alice X Yu, Matthew Mossanen, Benjamin I Chung, Steven L Chang

Division of Urology, Brigham and Women's Hospital, Boston, MA, USA., Center for Surgery and Public Health, Brigham and Women's Hospital, Boston, MA, USA., Harvard Medical School, Boston, MA, USA., Department of Urology, MedStar Washington Hospital Center, Washington, DC, USA., Department of Urology, Stanford University, Stanford, CA, USA.