Childhood tonsil and/or adenoid removal may be associated with long-term increased risks of diseases related to immune function

EBM Focus - Volume 13, Issue 26

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Reference: JAMA Otolaryngol Head Neck Surg 2018 early online

  • Evidence evaluating the long-term effects of childhood tonsil or adenoid removal is limited.
  • A retrospective cohort study of over 1 million children in Denmark evaluated associations between adenoidectomy, tonsillectomy, and adenotonsillectomy before age 9 and risks of subsequent (up to age 30) development of multiple diseases that may be affected by changes in immune function.
  • Childhood removal of tonsils and/or adenoids is associated with long-term modest increased risks of almost all evaluated diseases, particularly respiratory, allergic, and infectious diseases. These findings are limited by the retrospective and observational study design but should be considered when determining management for children with recurrent sore throats or other indications for tonsillectomy and/or adenoidectomy.

Tonsillectomy or adenotonsillectomy is performed in about 530,000 children every year in the United States, most commonly to address recurrent throat infections or sleep-related breathing disorders (Clin Pediatr (Phila) 2016, JAMA Pediatr 2015, Pediatrics 2015). They are regarded as routine and relatively safe surgeries, but evidence assessing the long-term effects of removing these lymphatic tissues is limited. To evaluate the long-term risks of developing diseases that may be impacted by changes in immune function, a retrospective cohort study of 1,753,100 children was conducted using Danish electronic medical records. Individuals born from 1979 to 1999 were assessed for adenoidectomy, tonsillectomy, or adenotonsillectomy before age 9 and subsequent (up to age 30) development of each of 28 target disease groups. Target disease groups were defined by ICD codes and included infectious, allergic, and respiratory diseases, as well as circulatory, endocrine, and other diseases that may be indirectly affected by immune dysfunction. Children were excluded if they were part of multiple gestations; had any of the 3 surgeries after age 9; had outlying weight, length, or parental age at birth; or had missing data for numerous covariates used in analyses. Also, for each target disease group, the analysis was restricted to children who were not diagnosed with a qualifying disease before age 9. A total of 1,218,351 children were included in the risk analyses. The risk with each of the 3 surgeries was assessed separately, and the p value determining statistical significance was adjusted for multiple comparisons (78 in total; 6 of a possible 84 assessments were not conducted due to insufficient power).

In the cohort, 1.4% of children had adenoidectomy, 1% had tonsillectomy, and 2.6% had adenotonsillectomy before age 9. Each of the 3 surgeries was associated with modest but significant increased risks of almost all target disease groups. The largest risks were observed for upper respiratory tract conditions, which occurred after age 9 in 10.77% of patients without surgery and had a relative risk (RR) with tonsillectomy of 2.72 (95% CI 1.54-4.8) and an RR with adenoidectomy of 1.99 (95% CI 1.51-2.63) (there was insufficient power to assess the risk with adenotonsillectomy). For several other disease groups, at least 1 surgery had a large increased risk (arbitrarily defined here as an RR with an upper limit of the 95% CI > 1.9). The single group of “any respiratory condition” had an RR of 1.48 (95% CI 1.13-1.95) with adenoidectomy and occurred in 20.19% without surgery, but there was insufficient power to assess risks with tonsillectomy or adenotonsillectomy. There were also large increased risks of allergic conjunctivitis and chronic obstructive pulmonary disease, but each condition occurred in < 0.3% without surgery.

Each of the surgeries were associated with smaller increased risks (upper limit of 95% CI < 1.9) for infectious/parasitic conditions, but the effect may be meaningful due to the high event rate of this disease group (12.1% without surgery). Similarly, several other disease groups were at a small increased risk with each of the surgeries but have at least a moderate event rate (5%-10%): lower respiratory tract conditions, any skin condition, any digestive condition, asthma, any eye/adnexa condition, and pneumonia. Finally, the 3 surgeries were not associated with long-term reduced risks of most conditions they aim to treat (other than tonsillitis): adenoidectomy was associated with a reduced risk of sleep disorders, but it was also associated with an increased risk of chronic sinusitis. Adenotonsillectomy was associated with an increased risk of sinusitis, and all 3 surgeries were associated with an increased risk of otitis media. None were associated with altered risks of abnormal breathing.

This study suggests that childhood removal of the tonsils and/or adenoids is associated with long-term modest increased risks of diseases that may be affected by changes in immune function, particularly respiratory, allergic, and infectious diseases. The retrospective and observational nature of this study limit conclusions to a description of an association; although numerous covariates were used in the risk analyses, confounding in a cohort study cannot be reduced to the levels of a randomized trial. For example, children who are prone to respiratory infections and other diseases or who are more likely to use the healthcare system may be more likely to have their tonsils and/or adenoids removed. The exclusion of children who were diagnosed with a qualifying disease before age 9 in the risk analysis for a target disease group mitigates this concern slightly, but the use of ICD codes alone to determine event rates does not capture many conditions that may affect overall health. Finally, potential confounding related to differential access to healthcare is reduced by using Danish health registries, but this also limits generalization to countries without universal healthcare systems. Nevertheless, previous evidence evaluating possible long-term risks of tonsil or adenoid removal is limited. The associations in this study, while being interpreted within the context of study limitations, should be considered when deciding between conservative and surgical management for children with recurrent sore throats or other indications for tonsil or adenoid removal.

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