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UBC Theses and Dissertations

Utility of the American College of Surgeons National Surgical Quality Improvement Program Surgical Risk Calculator to accurately predict postoperative outcomes after colon resection Al Lawati, Rihab


BACKGROUND: Predicting potential complications from surgery is a crucial step to aid decision to operate. The American College of Surgeons (ACS) initiated the National Surgical Quality Improvement Program (NSQIP) which collects and analyses patients’ outcomes from surgery. ACS NSQIP developed a Surgical Risk Calculator (RC) to predict risks of postoperative complications. Aim of this study was to assess RC accuracy for predicting complications in patients undergoing colon resection. METHODS: Validation study with secondary use of administrative data conducted in a tertiary care center. Patients who received colorectal procedures in our Enhanced Recovery After Surgery (ERAS) program from November 2013 to December 2015 were enrolled. RC predictions were calculated and compared with observed NSQIP outcomes within 30 days follow-up. Observed versus predicted outcomes were compared. RC accuracy was assessed by graphical examination of the model calibration for outcomes that exceeded 50 events. Predicted versus observed length of stay (days mean±SD) was compared. RESULTS: A total of 368 patients were enrolled. RC predicted versus observed outcomes (n) were: serious complication 40.3 vs. 51; any complication 60.5 vs. 70; surgical site infection (SSI) 31.8 vs. 51; pneumonia 5.8 vs. 15; cardiac complication 16.5 vs. 9; urinary tract infection 9.8 vs. 11; venous thromboembolism 4.8 vs. 4; acute renal failure 16.6 vs. 5; return to operating room 14.6 vs. 6; death 4.2 vs. 2; Discharge to facility 20.2 vs. 12. Good calibration was observed for any complication and serious complications. SSI was underestimated but RC adjustment by surgeon improved SSI prediction. Length of stay was inaccurately predicted: 4.4±1.3 predicted versus 8.6±12.1 days observed (p <0.01, Wilcoxon Rank Sum Test). CONCLUSION: Application of RC in our population closely predicts serious and any complication but less accurately predicts SSI unless adjusted by surgeon and inaccurately predicts length of hospital stay. All outcomes including the above require analysis of greater number of events to permit final conclusions on RC use.

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