Perforations and bleeding in a population-based cohort of all registered colonoscopies in Sweden from 2001 to 2013.

Background: The rates of perforation and bleeding are important quality measures of colonoscopy performance. Objective: The objective of this article is to assess the frequency of colonoscopy-related bleeding and perforation in Swedish counties and to relate these findings to patient characteristics. Method: Data on 593,308 colonoscopies performed on adults from 2001 to 2013 were retrieved from Swedish inpatient and outpatient registers. Covariates were assessed in a multivariate Poisson regression model. The correlation between perforation and bleeding was calculated with Pearson's bivariate correlation formula.
Results: The relative frequency of bleeding and perforation vary across counties (bleeding: 0.02%-0.27%; perforation: 0.02%-0.27%). There were significant positive correlations between the relative frequency of bleeding and perforation at the county level, both including (r = 0.792, p < 0.001) and excluding polypectomies r = 0.814 (p < 0.001). The relative risks of these conditions in the counties ranged from 0.12, p < 0.001, to 1.53, p = 0.05 (bleeding) and from 0.17, p = 0.002, to 2.42, p < 0.001 (perforation). Conclusions: There are substantial differences in colonoscopy performance in Sweden. These differences do not seem to be explained by patient characteristics.