A Randomized Controlled Study of Adenotonsillectomy for Children with Obstructive Sleep Apnea Syndrome (CHAT)

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Accession Number

Study Type
Clinical Trial

Collection Type
Open BioLINCC Study See bottom of this webpage for request information

Study Period
October 2007 – June 2012

NHLBI Division

Dataset(s) Last Updated
January 3, 2018


Commercial Use Data Restrictions No

Data Restrictions Based On Area Of Research No


The Childhood Adenotonsillectomy Trial (CHAT) was designed to evaluate the efficacy of early adenotonsillectomy versus watchful waiting with supportive care, with respect to cognitive, behavioral, quality-of-life, and sleep factors at 7 months of follow-up, in children with the obstructive sleep apnea syndrome.


Childhood obstructive sleep apnea syndrome is associated with numerous adverse health outcomes, including cognitive and behavioral deficits. The most commonly identified risk factor for the childhood obstructive sleep apnea syndrome is adenotonsillar hypertrophy. Thus, the primary treatment is adenotonsillectomy, which accounts for more than 500,000 procedures annually in the United States alone. However its usefulness in reducing symptoms and improving cognition, behavior, quality of life, and polysomnographic findings has not been rigorously evaluated.


A total of 464 children underwent randomization. Eligible children were 5 to 9 years of age, had the obstructive sleep apnea syndrome without prolonged oxyhemoglobin desaturation, and were considered to be suitable candidates for adenotonsillectomy. The obstructive sleep apnea syndrome was defined as an obstructive apnea–hypopnea index (AHI) score of 2 or more events per hour or an obstructive apnea index (OAI) score of 1 or more events per hour. Children with an AHI score of more than 30 events per hour, an OAI score of more than 20 events per hour, or arterial oxyhemoglobin saturation of less than 90% for 2% or more of the total sleep time were not eligible.


CHAT was a multicenter, single-blind, randomized, controlled trial at seven academic sleep centers. Children were randomly assigned to early adenotonsillectomy (surgery within 4 weeks after randomization) or a strategy of watchful waiting. At the baseline visit, children with coexisting conditions that could exacerbate the obstructive sleep apnea syndrome (e.g., allergies and poorly controlled asthma) were referred for treatment as needed. Children underwent standardized polysomnographic testing with scoring at a centralized sleep reading center, cognitive and behavioral testing, and other clinical and laboratory evaluations at baseline and 7 months after randomization. At both examinations, caregivers were asked to complete survey instruments, and teachers were mailed behavioral assessments. The primary study outcome was the change in the attention and executive-function score on the Developmental Neuropsychological Assessment.


As compared with a strategy of watchful waiting, surgical treatment for the obstructive sleep apnea syndrome in school-age children did not significantly improve attention or executive function as measured by neuropsychological testing but did reduce symptoms and improve secondary outcomes of behavior, quality of life, and polysomnographic findings, thus providing evidence of beneficial effects of early adenotonsillectomy.

N Engl J Med. 2013 Jun 20;368(25):2366-76.

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