Rates and risk factors for subsequent tonsillectomy after prior adenoidectomy: a regression analysis.

OBJECTIVE To determine the role of adenoidectomy without concurrent tonsillectomy in the treatment of upper airway obstruction, by determining rates and risk factors for subsequent tonsillectomy. DESIGN Retrospective cohort study with nested case-control study. Data were evaluated using Kaplan-Meyer curves with Cox proportional hazards regression analysis, as well as contingency table and logistic regression analysis. SETTING Tertiary care pediatric hospital with satellite clinics and surgical centers. PATIENTS A total of 2462 patients aged 5 months to 18 years undergoing adenoidectomy without concurrent tonsillectomy. MAIN OUTCOME MEASURES A 5-year database was searched for birth dates, dates of initial surgery, and dates of subsequent tonsillectomy (if performed) or latest follow-up. Cases (tonsillectomies) were then matched 1:1 by age with controls (no subsequent tonsillectomy). Medical charts were reviewed to identify potential predisposing factors, including sex, tonsil size, and adenoidectomy or tonsillectomy indication. RESULTS Within 5.4 years, 108 patients underwent subsequent tonsillectomy. The relative risk of subsequent tonsillectomy decreases by 0.83 (95% confidence interval, 0.78-0.88) for each increasing year of age at adenoidectomy. The odds of undergoing a future tonsillectomy significantly increase with increasing tonsil size at the time of adenoidectomy. There was a trend toward doubling the risk of subsequent tonsillectomy when the adenoids were removed for upper airway obstruction (including obstructive sleep apnea) compared with other indications (P = .06). CONCLUSION Knowledge of the rates and risk factors for subsequent tonsillectomy will allow more informed counseling of parents regarding whether tonsillectomy should be performed or deferred at the time of an indicated adenoidectomy.