Increased risk of appendectomy due to appendicitis after tonsillectomy in women: A longitudinal follow-up study using a national sample cohort

The purpose of this study was to evaluate the risk of appendectomy due to appendicitis after tonsillectomy in Koreans using national cohort data. Using the national cohort study from the Korean Health Insurance Review and Assessment Service, 1:4 matched tonsillectomy participants (9015) and control participants (36,060) were selected. The Cox-proportional hazard model was used. In this analysis, a crude and adjusted model for age, sex, income, region of residence, and the past medical histories of hypertension, diabetes mellitus, and dyslipidemia were used. For the subgroup analyses, the participants were divided as follows: children (≤14 years old) vs adolescents and adults (≥15 years old) and men vs women. The adjusted hazard ratio (HR) of tonsillectomy for appendectomy was 1.06 (95% confidence interval, CI = 0.89–1.27, P = .517). In the subgroup analysis, the HR was 1.03 (95% CI = 0.82–1.30, P = .804) in children and 1.10 (95% CI = 0.84–1.47, P = .468) in adolescents and adults. In another subgroup analysis, the HR was 0.89 (95% CI = 0.70–1.12, P = .314) in men and 1.39 (95% CI = 1.06–1.83, P = .018) in women. The risk of appendectomy was higher in the tonsillectomy group but only in women.