Tonsillectomy increases the risk of retropharyngeal and parapharyngeal abscesses in adults, but not in children: A national cohort study

OBJECTIVES The purpose of this study is to evaluate the risk of retropharyngeal and parapharyngeal abscesses (deep neck infection) after tonsillectomy in Koreans using national cohort data. METHODS Using the national cohort study from the Korean Health Insurance Review and Assessment Service, participants who had undergone a tonsillectomy (5,299) and control participants (21,196) were selected and matched 1:4 (for age, sex, income, region of residence, and pre-operative upper respiratory infection visits). The Cox-proportional hazard model was used. A crude model and an adjusted model for age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia were used in this analysis. For the subgroup analyses, the participants were divided into 2 groups: children (≤ 14 years old) and adolescents and adults (≥ 15 years old). RESULTS The adjusted hazard ratio of deep neck infection after tonsillectomy was 1.43 (95% confidence interval, CI = 1.18-1.72, P < 0.001). In subgroup analysis, this ratio was 1.12 (95% CI = 0.86-1.47, P = 0.390) in children and 1.87 (95% CI = 1.43-2.45, P < 0.001) in adolescents and adults. The crude hazard ratios were almost the same as the adjusted ratios. CONCLUSION The risk of deep neck infection was higher in the tonsillectomy group. The subgroup analysis showed a similar finding in the adolescent and adult group but not in the child group.