Hospital Variation in Outcomes following Appendectomy in a Regional Quality Improvement Program

Objective To determine hospital variation in clinical outcomes following appendectomy for acute appendicitis. Methods Using data from the Michigan Surgical Quality Collaborative (MSQC), we selected patients with procedure codes for open or laparoscopic appendectomy with a diagnosis of acute appendicitis (2006—2011). We used multivariate regression models for risk adjustment of patient level factors and reliability adjustment for sample size differences between hospitals. Adjusted rates of outcomes for each hospital were generated by multiplying ratios of observed to expected events by overall mean event rates. Results During the study period, 12,410 patients underwent appendectomies in 49 participating MSQC hospitals. Neither the mortality rate nor the rate of superficial or deep surgical site infection demonstrated significant variation. However, significant variation was observed for all other clinical outcomes, including a 14-fold difference the rate of post-operative sepsis and septic shock. Conclusion We found significant hospital variation in outcomes following appendectomy and identified missing variables that could help to explain the observed variation. These findings have been used to enhance ongoing quality improvement efforts across the state of Michigan.