High complication rate among patients undergoing appendectomy in Ontario: a population-based retrospective cohort study

Background — Appendectomy is a common emergency procedure. The risks have been reported in previous studies but often are limited to inpatient complications. The purpose of this study was to describe inpatient and outpatient rates of complications associated with appendectomy in a contemporary population-based cohort and explore factors associated with these complications.

Methods — We conducted a retrospective study using linked data for Ontario within Institute for Clinical Evaluative Sciences databases. Patients who underwent emergent appendectomy between 2009 and 2014 were included. The primary outcome was a complication (death, readmission, emergency department visit, lengthy [> 7 d] hospital stay, percutaneous abscess drainage, reoperation or 1 of the predefined complication codes) occurring within 30 days of surgery. We used modified Poisson regression to identify predictors of complications.

Results — A total of 50 369 patients underwent emergent appendectomy over the study period, of whom 16 953 (33.7%) had a perforated appendix. Overall, 14 451 patients (28.7%) (8428 [25.2%] in the nonperforated group and 6023 [35.5%] in the perforated group) had at least 1 complication. The most common complication was an emergency department visit (7942 patients [15.8%]), followed by surgical site infection (4792 [9.5%]). Increasing age, female sex, rural residence, perforation status, daytime surgery and open surgical technique were associated with increased risk of complications.

Conclusion — We found a higher rate of complications after appendectomy than previously reported. The most common complication was presentation to the emergency department. Our definition of complications is more inclusive than in previous studies and provides a deeper understanding of complications after appendectomy.

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