The efficacy of tonsillectomy, adenoidectomy, and T&A on otitis media has been investigated in many studies. Currently in the United States, tympanostomy tubes, adenoidectomy, or both are recommended for otitis media with effusion in patients age 4 or older based on several systematic reviews [6, 13,14,15]. Adenoidectomy is not recommended in patients younger than 4 if there are no distinct indications such as nasal obstruction or chronic adenoiditis .
The pathophysiology of otitis media includes dysfunction in ventilation, drainage of secretion, and mucosa edema due to negative pressure caused by Eustachian tube dysfunction. Adenoidectomy may enhance Eustachian tube function, which would improve ventilation and drainage and help control pressure in the middle ear. In contrast, tonsillectomy alone may not be a helpful treatment for otitis media because tonsils are not anatomically associated with Eustachian tube function. Biofilms of bacteria in the adenoid have been reported to cause inflammation and mucosal edema, resulting in otitis media [5, 16, 17]. Paradise et al. suggested that otitis media could be associated with infection not only in the nasopharynx, but also in the oropharynx based on their results that T&A was narrowly more efficacious against otitis media than adenoidectomy only .
The effect of T&A on the use of medical services has been reported in several studies. Tarasiuk et al. reported reductions in total annual health care costs, number of new admissions, emergency department visits, number of consultations, and prescribed drugs in children with obstructive sleep apnea syndrome who had T&A . Using Medicaid data from the United States, Chang et al. reported a reduction in costs after T&A in children with adenotonsillar hypertrophy due to less antibiotic use and fewer outpatient visits . However, these studies analyzed visits and the costs of diseases other than otitis media. Furthermore, the characteristics of patients included in our study are different from those of previous studies. We included patients from a national database that included a representative population with data on whole-household income.
We did not find any significant differences in number of medical services used in association with otitis media between surgery and non-surgery groups before and after surgery. Similarly, the cost of medical services used in association with otitis media was not significantly different between the two groups after surgery. Medical service costs, however, were significantly higher in the surgery group 1 year before surgery. Overall, T&A did not appear to help decrease the number or cost of medical services used in association with otitis media.
The abrupt increase in the cost of medical services used in association with otitis media observed in the T&A group but not the non-T&A group 1 year before surgery is difficult to explain. It could be attributable to the cost associated with preoperative workups before undergoing general anesthesia, including complete blood count, blood chemistry, chest plain radiography, and electrocardiography. Although these costs are not directly associated with otitis media, many of the patients who underwent preoperative workups might have had accompanying otitis media, and the main diagnostic codes of some patients might have been the codes associated with otitis media. No medical services except preoperative workups could have caused such an abrupt increase in costs just before surgery.
Considering this, the continued decrease in cost in the T&A group immediately after surgery does not demonstrate effectiveness of T&A for otitis media. If T&A were effective for otitis media, both the number and cost of medical services used in association with otitis media would become significantly lower in the T&A group than in the non-T&A group after surgery. The cost of medical services used in association with otitis media decreased with time after surgery in both groups. This could be attributed to a spontaneous decrease of otitis media occurrence. Based on the results of this study, it seems that T&A is not related to otitis media regarding number and cost of medical services.
Although this study was retrospective in nature and based on National Health Insurance Service data, and although the data were analyzed by diagnostic codes, we believe that the relationships between T&A and otitis media with respect to medical services used were effectively evaluated for a sample cohort that represented the wider population. The T&A and non-T&A groups in this study had similar sociodemographic characteristics, and the object of the study was to investigate differences in the number and cost of medical services used by the two groups. Thus, the effects of other factors, such as sex, age, income, residence, and factors that can influence the incidence of otitis media (such as allergies and other comorbidities), were not investigated using multivariate regression analysis. Also, detailed costs for consultation fees, workups, and treatment procedures could not be compared between the two groups, as the National Sample Cohort database only contained data on the total cost of medical services used in association with otitis media. Nonetheless, this research is significant because it is the first study to use population-based data to investigate the effect of T&A on the use of medical services related to otitis media.
Patients who underwent adenoidectomy alone or tonsillectomy alone were not included in this study because there were few of them. A future study that designates more surgery classifications (e.g., tonsillectomy alone, adenoidectomy alone, and T&A) may provide more meaningful results. Population-based studies may also be important for national health authorities to identify medical services used in association with otitis media and to manage national health insurance funds appropriately.