Effect of Present at Time of Surgery (PATOS) on Outcomes in Pancreatic Surgery

Abstract

Introduction: While there is some data available on the importance of accounting for the effect of present at time of surgery (PATOS) when estimating unadjusted postoperative complication rates, little is known about the impact of PATOS on outcomes in patients undergoing pancreatic surgery specifically. By taking PATOS into account, we hypothesized that unadjusted, observed postoperative complication rates might be reduced, with these reductions being different across outcomes; however, we expected fewer differences in risk-adjusted results, i.e., observed to expected ratios (O/E ratios).

Methods: We retrospectively analyzed the ACS NSQIP Participant Use Files (PUFs) from 2015 to 2019. PATOS data were analyzed for the 8 postoperative complications of superficial, deep, and organ space surgical site infection; pneumonia; urinary tract infection; ventilator dependence; sepsis; and septic shock. Postoperative complication rates were compared by ignoring PATOS vs. taking PATOS into account.

Results: Of the 31,919 patients in the ACS NSQIP PUFs who underwent pancreatic surgery, 1120 (3.51%) patients had one or more PATOS conditions. The event rates after taking PATOS into account declined for all outcomes-superficial surgical site infection (SSI) rates reduced by 2.56%, deep SSI rates reduced by 4.28%, organ space SSI rates reduced by 9.31%, pneumonia rates reduced by 2.91%, urinary tract infection rates declined by 4.69%, and septic shock rates declined by 9.27%.

Conclusion: Our paper highlights that accounting for PATOS is important for estimating unadjusted postoperative complication rates in patients undergoing pancreatic surgery. Risk adjustment is essential to any attempt at quality assessment and benchmarking. Failure to account for PATOS may penalize surgeons who care for the sickest and most complicated patients and subsequently encourage cherry-picking of less risky patients and procedures.