AUA 2019: Development and Validation of a Risk Score Based on Patient Characteristics to Predict Major Complications after Partial Nephrectomy

Chicago, IL ( The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) Surgical Risk Calculator (SRC) is an evidence-based clinical tool that involves patient comorbidities used to assess preoperative surgery risk. One recent study found that the SRC performed well at predicting complications after acute care surgeries.1 In urology, the nephrometry score has been found to correlate with postoperative complication rates after partial nephrectomy. Unlike the nephrometry score that correlates specific tumor characteristics and complication rates, Dr. Melissa J. Huynh and colleagues developed and validated a risk score that could predict the probability of major postoperative complications based on patients’ specific comorbidities.

Utilizing the Premier Healthcare Database, Dr. Yu explained that the group identified patient comorbidities and major (Clavien grade 3-5) surgical complications using ICD9 codes. They utilized data from half of the set of patients to develop the risk score, and they used the other half for the purpose of validation.

In total 26,778 partial nephrectomies were identified from the database performed between 2003 and 2015. The major complication rate was 5.6% for the entire cohort. The group’s final risk scoring scheme for predicting complication risk involved 9 total predictors. (Table 1) The predicted probabilities for any Clavien grade 3-5 complication varied by risk category that involved four groups: low (score <3), intermediate (score 4-11), high risk (score 12-30), and very high risk (score >30). For low risk, there was a 2.6% chance of having a major complication, for intermediate, high, and very high risk, the probabilities were 4.6%, 17.6%, and 40.7%, respectively. In conclusion, Huynh and colleagues both developed and validated a risk scoring system to predict postoperative complications for partial nephrectomy that takes into account patient comorbidities.

This group should be lauded for their impressive work that involved sizable numbers. This is an important advancement for preoperative surgical risk counseling. Sometimes there is a mismatch between what patients want and what surgeons might think would be best for them. A relatively frail patient may want to have surgery done to remove a tumor mass due to various factors but having objective numbers for the patient may provide real, tangible information for patients. This both facilitates patient counseling and education and enhances the entire informed consent process.

Table 1. Scoring scheme for predicted risk of complications following partial nephrectomy.


Presented by: Alice X. Yu, MD, Department of Urology, Massachusetts General Hospital, Boston, Massachusetts 

Written by: John Sung (@JohnM_Sung), Medical Student Texas A&M University, College of Medicine, Dallas, Texas, Research Fellow, University of California, Irvine Department of Urology atthe American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois

1. Golden DL, Ata A, Kusupati V, et al. Predicting Postoperative Complications after Acute Care Surgery: How Accurate Is the ACS NSQIP Surgical Risk Calculator? Am Surg. 85(4):335-341. 2019