Comparison of observed to predicted outcomes using the ACS NSQIP risk calculator in patients undergoing pancreaticoduodenectomy.

BACKGROUND: Postoperative outcomes predicted by the ACS NSQIP universal risk calculator have not been validated for specific procedures like pancreaticoduodenectomy (PD).

METHODS: A random sample of 400 PD patients from the NSQIP database was analyzed. Patients were categorized into four groups of 100 each based on ICD-9 diagnosis (211.6, 157.0, 156.2, and 577.1). Estimated risks of postoperative outcomes recorded by the calculator were compared to observed outcomes using the Brier Score (BS). The calculated BS was compared to a null model BS. A BS of zero indicated perfect prediction, while a BS of one indicated the poorest prediction.

RESULTS: BS for all groupings was generally low, reflecting good prediction. BS for any and major complications was higher (0.23 and 0.22, respectively). This was also seen within ICD-9 subgroups. For patients with ampullary cancer, BS for these outcomes was higher (0.27 and 0.26, respectively). Comparison to the null model BS (0.24 and 0.24, respectively) correlated lesser predictive accuracy of the calculator for this subgroup.

CONCLUSIONS: The ACS NSQIP risk calculator, although accurate in predicting outcomes in patients undergoing PD, shows variation when accounting for specific ICD-9 diagnoses. Incorporating the diagnosis may better guide surgeons and patients preoperatively in making informed decisions. J. Surg. Oncol. 2016;114:157-162. © 2016 Wiley Periodicals, Inc.