A Nationwide Registry-Based Cohort Study Of Incidence Of Tonsillectomy In Denmark, 1991-2012

Objective: To update tonsillectomy incidence rates in Denmark and identify whether the incidence rates vary between geographical areas in the country during the period 1991-2012. Design: This was a retrospective nationwide cohort study using data from the comprehensive Danish patient registries. Data included surgical code, gender and date of birth, date and place of surgery. Setting: Hospitals and private oto-, rhino-, laryngology (ORL) offices. Participants: Danes who underwent tonsillectomy in the period 1991-2012. Main outcome measure: Tonsillectomy. Results: In the 22-year period, 177 211 tonsillectomies were conducted, and the overall incidence of tonsillectomy decreased significantly over time. The overall annual incidence of tonsillectomies decreased from 155.7 per 100 000 inhabitants in 1991 to 129.4 per 100 000 inhabitants in 2012. In 1991, 5.5% of tonsillectomies were performed in office settings, while in 2012, it had increased to 26.6% (P <.01). The highest incidence of tonsillectomy was found in children between 3 and 4 years of age (predominance of males, P <.01) and in 15-to 19-year-olds (predominance of females, P <.01). Each year, 0.44% of children underwent tonsillectomy, and by the age of 20, 7.7% of the Danish people has had a tonsillectomy. There were significant regional differences in the number of tonsillectomies. Conclusion: The incidence rate of tonsillectomies in Denmark decreased significantly in the study period, but with great regional variance.