Evaluation of the American College of Surgeons National Surgical Quality Improvement Program Surgical Risk Calculator in Gynecologic Oncology Patients Undergoing Minimally Invasive Surgery

Study Objective

To evaluate the ability of the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) surgical risk calculator to predict discharge to postacute care and perioperative complications in gynecologic oncology patients undergoing minimally invasive surgery (MIS).

Design

A retrospective chart review (Canadian Task Force classification II-1).

Setting

A university hospital.

Patients

All patients undergoing MIS on the gynecologic oncology service from January 1, 2009, to December 30, 2013.

Interventions

Surgical procedures were reviewed, and appropriate Common Procedural Terminology codes were assigned. Twenty-one preoperative risk factors were abstracted from the chart and entered into the ACS NSQIP surgical risk calculator. The predicted risk of discharge to postacute care and 8 additional postoperative complications were calculated and recorded. Actual postoperative complications were abstracted from the medical record. The association between the calculated risk and the actual outcome was determined using logistic regression. The ability of the calculator to accurately predict a particular event was assessed using the c-statistic and Brier score.

Measurements and Main Results

Of the 876 patients reviewed, a majority underwent hysterectomy (71.6%), with almost half of those patients undergoing additional cancer staging procedures (34.8%). Although the calculator was a poor predictor of postoperative complications, it was a strong predictor for discharge to postacute care (c-statistic = 0.91, Brier score = 0.02) with an odds ratio of 2.31 (95% confidence interval, 1.65–3.25; p < .0001).

Conclusion

The ACS NSQIP surgical risk calculator does not accurately predict postoperative complications or length of stay in gynecologic oncology patients undergoing MIS. Although it was a strong predictor of need for discharge to postacute care, it vastly overestimated the number of patients requiring this service. Therefore, the calculator's risk score for discharge to postacute care may be considered during preoperative counseling but should not be a predictor of whether or not the patient should proceed with surgery.