Objectives: The rates for colonoscopy-associated adverse events vary considerably worldwide. In Sweden, the figures are known to a limited extent. We assessed the frequency of severe colonoscopy-related adverse events and the impacts of different risk factors, including the use of general anaesthesia.
Material and methods: This is a retrospective population-based cohort study of the colonoscopies performed during the years 2001-2013 on adults identified in the Swedish health registers. The rates for bleeding, perforation, splenic injury and 30-day mortality were calculated. Covariates for risks were assessed in a multivariate Poisson regression model.
Results: There were 593,315 colonoscopies performed on the 426,560 individuals included in the study. The rates for colonoscopy-related bleeding and perforation were 0.17% and 0.11%, respectively. When polypectomy was performed, the rates were 0.53% for bleeding and 0.25% for perforation. There were 31 splenic injuries (1:20,000 colonoscopies) reported. The crude 30-day death rate for colonoscopy was 0.68%. Of those diagnosed with bleeding or perforation, 5.6% and 6.1% were dead within 30 days, respectively. The multivariate RR for perforation when general anaesthesia was employed was 2.65 (p < .001; 95%CI 1.71-4.12).
Conclusions: The perforation rate seemed to be relatively high in an international perspective. General anaesthesia was associated with a significantly higher risk for perforation. Splenic injuries were more frequent than expected.
Keywords: Register based; adverse events; anaesthesia; colonoscopy; national population study.