A higher hospital case mix index increases the odds of achieving a textbook outcome after hepatopancreatic surgery in the Medicare population.

Abstract Background The objective of the current study was to assess the impact of case mix index at the hospital level on postoperative outcomes among Medicare beneficiaries who underwent hepatopancreatic surgery. Methods Medicare beneficiaries who underwent hepatopancreatic surgery between 2013 and 2017 were identified and analyzed. The primary independent variable, Case Mix Index, is a freely available metric; the primary outcome was textbook outcome defined as the absence of complications, extended length of stay, readmission, and mortality. Results Among 37,412 Medicare beneficiaries, 64.9% (n = 24,299) underwent a pancreatectomy and 35.1% (n = 13,113) underwent hepatectomy. The overall incidence of textbook outcome was 47.2%, which varied by case mix index (low case mix index: 41.6% vs high case mix index: 51.3%), as did extended length of stay (low case mix index: 27.9% versus high case mix index: 19.3%), complications (low case mix index: 33.3% vs high case mix index: 24.7%), and 90-day mortality (low case mix index: 12.5% vs high case mix index: 6.3%). After controlling for hepatopancreatic-specific surgical volume and hospital teaching status, multivariable analyses revealed that patients who underwent surgery at a low case mix index hospital had 28% decreased odds (95% confidence interval 0.66–0.79) of achieving a textbook outcome versus patients from a high case mix index hospital. Moreover, patients at a low case mix index hospital had 39% increased odds of extended length of stay (95% confidence interval 1.23–1.59), 48% increased odds of experiencing a complication (95% confidence interval 1.32–1.65), and 56% increased odds of 90-day mortality (95% confidence interval 1.31–1.87). Conclusion Case mix index was strongly associated with the probability of achieving a textbook outcome after hepatopancreatic surgery. Hospitals with a higher case mix index were more likely to perform hepatopancreatic surgeries with no adverse postoperative outcomes.