Predictive validity of ACS-NSQIP risk calculator in ovarian cancer patients undergoing interval debulking surgery

Abstract

Objectives: To determine whether the American College of Surgery-National Surgery Quality Improvement Program (ACS-NSQIP) risk calculator accurately predicts postoperative complications and length of stay in patients undergoing interval debulking surgery (IDS) for advanced stage epithelial ovarian cancer. Methods: Pre-operative risk factors, post-operative complication rates, and Current Procedural Terminology codes were abstracted from records of ovarian cancer patients managed with IDS from 01/2010-07/2015. A power calculation was done to estimate the minimum number of complications needed to evaluate accuracy of the ACS-NSQIP risk calculator. Predicted risk compared with observed risk was calculated using logistic regression. The predictive accuracy of the ACS-NSQIP risk calculator in estimating post-operative complications or length of stay (LOS) was assessed using c-statistics and Briar scores. Complications with a c-statistic of >0.70 and Brier score of Results: 261 patients underwent IDS, encompassing 21 unique CPT codes. Readmission(n=25), surgical site infection(n=35), urinary tract infection(n=35), and serious postoperative complications(n=57) met the minimum event threshold (n>10). All predicted complication rates fell within the interquartile range of the observed incidence rates, however the ACS-NSQIP calculator demonstrated neither discriminative ability nor accuracy for any postoperative complications based on c-statistics and Brier scores. The calculator accurately predicted LOS within 1 day for only 32% of patients and could not accurately predict patients likely to have a prolonged LOS (c-statistic=0.65). Download : Download high-res image (99KB) Download : Download full-size image Conclusions: Among patients undergoing IDS, the ACS-NSQIP did not accurately discriminate which patients were at increased risk of complications or extended LOS. The risk calculator should be considered to have limited utility in informing preoperative counseling or surgical planning.