Temporal trends in postoperative outcomes after major abdominal surgery: a population-based cohort study

Background: Enhanced recovery after surgery protocols and minimally invasive surgery are strategies to mitigate postoperative complications, therefore complication rate is expected to decrease over time. We estimated temporal trends and variation in clinical and health system outcomes. Methods: This was a population-based cohort study in Ontario, Canada, using data from the Institute of Clinical Evaluative Science. Male and female adults who underwent major elective abdominal surgery (gastroesophagectomy, pancreaticoduodenectomy, partial hepatectomy, colorectal resection) during 2005–21 were included. The primary outcome was a composite of moderate-to-severe postoperative complications. Secondary outcomes were health system outcomes. The primary analyses estimated aggregate unadjusted, and case-mix adjusted, linear trends. Results: We included 148 725 patients. The yearly rate of moderate-to-severe complications was similar (rate ratio [RR] 0.994, 95% confidence interval [CI] 0.985–1.002). Temporal improvements in length of stay (RR 0.968, 95% CI 0.959–0.977), ICU admission (RR 0.982, 95% CI 0.966–0.998), days alive and at home (RR 1.004, 95% CI 1.003–1.005), and total costs (RR 0.990, 95% CI 0.982–0.997) were estimated. Temporal improvements in complication rates were seen for colorectal resection (RR 0.988, 95% CI 0.980–0.997) and gastroesophagectomy (RR 0.985, 95% CI 0.974–0.996), whereas complication rates for partial hepatectomy (RR 1.012, 95% CI 1.003–1.022) and pancreaticoduodenectomy (RR 1.016, 95% CI 1.004–1.028) increased over time. Conclusions: Despite advances in perioperative protocols and techniques, the overall adjusted rate of moderate-to-severe complications did not change over time. Contrasting trends were evident between different surgical procedures. OSF protocol registration: https://doi.org/10.17605/OSF.IO/792BR.