Adenotonsillectomy vs Watchful Waiting in Pediatric Mild to Moderate Obstructive Sleep Apnea: The KATE Randomized Clinical Trial.

Importance: Adenotonsillectomy (ATE) is the standard procedure to treat children with obstructive sleep apnea (OSA). Objective: To investigate whether ATE is more effective than WW for treating otherwise healthy children with mild to moderate OSA. This randomized clinical trial (RCT) of young children investigated the benefit of ATE compared with watchful waiting (WW) after 3 years. Design, Setting, and Participants: The Karolinska Adenotonsillectomy (KATE) RCT was conducted between 2014 and 2020 with a 3-year follow-up and included children aged between 2 to 4 years with an Obstructive Apnea-Hypopnea Index (OAHI) score of 2 or greater and less than 10 at the otorhinolaryngology department of the Karolinska University Hospital in Stockholm, Sweden. All children were randomized to ATE (n = 29) or WW (n = 31). Interventions: ATE in children with OSA. Data were collected and analyzed in 2023. Main Outcomes and Measures: Results from polysomnography (PSG) and OSA-18 questionnaire were compared between the groups with the difference between changes in OAHI as the primary outcome. Children in the WW group underwent surgical treatment (crossovers) if remaining signs of OSA; OAHI score greater than 1 and/or severe symptoms, and were offered follow-ups but excluded from the per protocol analysis. Results: A total of 48 of 60 children (80%) (ATE n = 23, WW n = 16, crossovers n = 9) completed the study. Thirty-nine of 60 children (65%) were analyzed per protocol, 23 (59%) from the ATE group, 16 (41%) from the WW group. No group difference was seen in changes of OAHI (Cohen d, 0.05; 95% CI, -0.7 to 0.6), but a difference of medium effect size (Cohen d, 0.54; 95% CI, -1.3 to 0.1) when comparing changes in total OSA-18 score, in favor of ATE. Thirteen of 31 children (42%) in the WW group crossed over to surgery, follow-up PSG in 9 showed normalized OAHI after ATE. The crossover group had at baseline more of moderate OSA (Cohen d, 0.8; 95% CI, -1.5 to -0.5), higher total OSA-18 score (Cohen d, 0.8; 95% CI, -1.5 to 0.0), and larger tonsils (Cohen d, 1.3; 95% CI, -2.1 to -0.5) compared with nonoperated. Conclusions and Relevance: This small long-term RCT suggests that ATE was not more effective than WW. However, almost half of the children in the WW group had remaining signs of OSA and underwent surgery. Altogether, the results indicate that children with mild signs of OSA and small tonsils could be recommended WW. Trial Registration: ClinicalTrials.gov Identifier: NCT02315911.