Geographic Variation in Appendiceal Perforation Rates in Canada: a Population-Based Cohort Study

Background We hypothesized that patients living in rural neighborhoods experience delayed access to surgical services manifesting in increased appendiceal perforation rates in cases of appendicitis. Methods This population-based cohort study included adult patients with acute appendicitis in Canada (excluding Quebec) between April 2008 and March 2015. The main outcome of interest was rate of perforation. Predictors of interest included socioeconomic, geographic, and individual predictors of perforation. Spatial analysis was used to analyze spatial clustering of perforation. Results We identified 143,195 patients throughout the course of the study. The average perforation rate across our study was 35.9% (n = 51,456). Cluster analysis identified 286 (24%) neighborhoods with perforation rates greater than the average. Rural neighborhoods had a 1.89 times higher odds of being in a high perforation cluster (95% CI 1.08-3.08, p = 0.024). Compared to neighborhoods > 75 km from the admitting hospital, closer neighborhoods were less likely to be in a high perforation cluster (0-35 km OR 0.64, 95% CI 0.38-0.98, p = 0.049; 36-75 km OR 0.60, 95% CI 0.37-0.92, p = 0.019). Patients admitted to small community hospitals had a 0.51 times lower odds of perforation than those admitted to academic centers (95% CI 0.47-0.54, p < 0.001) and those who lived in high perforation clusters had a 1.42 times higher odds of perforation (95% CI 1.39-1.46, p < 0.001). Conclusion Neighborhoods located far from hospitals have increased appendiceal perforation rates. Also, patients with appendicitis treated at small community hospitals have significantly lower odds of perforation. From a policy point of view, patients with symptoms of appendicitis can be safely treated at the nearest hospital.