To evaluate the effect of tonsillectomy on the subsequent risk of pneumonia in an adult population, a longitudinal follow-up case control study was conducted using a national health screening cohort dataset between 2003 and 2012. A total of 1005 tonsillectomy participants were 1:4 matched with 4020 control participants for age, sex, income, and region of residence. The number of pneumonia diagnoses were counted from the index date (ID) to the date after the first-year (post-ID 1y), second-year (post-ID 2y), and third-year (post-ID 3y) periods. Simple linear regression and multiple linear regression were conducted to calculate estimated values (EVs) and 95% confidence intervals for each post-ID pneumonia and compared between the two groups. Subgroup analyses were performed according to age, sex, and the number of pneumonia cases during the year prior to the ID (pre-ID 1y). In the simple linear regression model, post-ID pneumonia did not show a significant correlation with tonsillectomy (post-ID 1y: EV = 0.003; post-ID 2y: EV = 0.007; post-ID 3y: EV = 0.013; all p > 0.05). In the multiple regression model, post-ID pneumonia also did not show a significant correlation with tonsillectomy (post-ID 1y: EV = 0.001; post-ID 2y: EV = 0.006; post-ID 3y: EV = 0.011; all p > 0.05). In the subgroup analyses, tonsillectomy did not show a significant correlation with post-ID pneumonia in either the simple linear regression or multiple linear regression models (all p > 0.05). Tonsillectomy performed in the adult population did not show any effect in increasing the incidence of pneumonia during the first three postoperative years.
Keywords: adult population; immunity; pneumonia; population health; tonsillectomy.