Predictors of Tonsillectomy after Previous Adenoidectomy for Upper Airway Obstruction

Objective. (1) Characterize risk factors for subsequent tonsillectomy in pediatric patients undergoing primary adenoidectomy for upper airway obstruction. (2) Compare rates of subsequent tonsillectomy between adenoidectomy patients with and without upper airway obstruction. Study Design. Historical cohort study with a nested case-control study. Cohort data were analyzed using KaplanMeier plots and a multiple regression model. Case- control data were analyzed using logistic regression. Subjects and Methods. Patients undergoing adenoidectomy without tonsillectomy at the University of Missouri between 1995 and 2010 were identified using billing records and selected chart review. A nested case- control study with detailed chart review was conducted to determine predictors of subsequent tonsillectomy in patients with upper airway obstruction. Results. Of 1291 patients identified in the historical cohort, 7.8% later underwent tonsillectomy. Age younger than 3 years (P = .027), female sex (P < .0001), and upper airway obstruction (P = .001) were found to be significant predictors of subsequent tonsillectomy. In the nested case- control study, potential predictors investigated included adenoidectomy indications, symptoms, smoke exposure, weight, comorbidities, and tonsil size at the time of adenoidectomy. Of these, only tonsil size was significant, with an increased odds of future tonsillectomy of 2.5 (P = .01) for each unit increase in tonsil size. Conclusion. Patients undergoing adenoidectomy for upper airway obstruction are likely to be at an increased risk of subsequent tonsillectomy when compared with those with other indications. Within this subgroup of patients with upper airway obstruction, young age, female sex, and large tonsil size may further increase the risk of subsequent tonsillectomy.