Accuracy of National Surgery Quality Improvement Program Models in Predicting Postoperative Morbidity in Patients Undergoing Colectomy

BACKGROUND: The National Surgery Quality Improvement Program (NSQIP) is the standard for assessment of acuity-adjusted outcomes in surgery. The validity of NSQIP has not been well established in colorectal surgery. Technical and process variables, which NSQIP may not consider, affect morbidity rate. OBJECTIVE: A retrospective observational study was undertaken to determine the accuracy of NSQIP models in predicting morbidity for patients undergoing laparoscopic or open colectomy. METHODS: NSQIP participant use files for 2005 to 2008 were obtained. Data were selected using Current Procedural Terminology coding for open or laparoscopic colectomy. NSQIP-generated predicted morbidities were used to create area under the receiver operator curves (AUROCs). RESULTS: AUROCs demonstrated an accurate predictive model if the value was above 0.8 and indicated a marginal predictor mode if below 0.7. The AUROC for the general NSQIP model was 0.817 (confidence interval [CI] = 0.815-0.819, p < 0.001). AUROC for the combined laparoscopic and open colectomy group was 0.703 (CI = 0.698-0.709, p value < 0.001). AUROCs for the individual laparoscopic and open colectomy groups were 0.627 (CI = 0.615-0.640, p < 0.001) and 0.701 (CI = 0.695-0.707, p < 0.001). CONCLUSION: This study demonstrates that although NSQIP-generated morbidities used to create AUROCs are accurate for patients in an overall surgical model, predictive models for morbidity are marginal for laparoscopic and open abdominal colectomies. NSQIP risk models tend to emphasize comorbidities rather than intraoperative details or technical aspects of colonic resections.