METHODS
The Childhood Adenotonsillectomy Trial (CHAT) was a single-blind,
randomized, controlled trial at seven academic sleep centers
(ClinicalTrials.gov number, NCT00560859). Methodologic details have been
published previously [13]. Briefly, eligible children aged 5 to 9
years, with OSA syndrome (OSAS) without prolonged oxyhemoglobin
desaturation considered suitable candidates for AT were enrolled. OSAS
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, arterial
oxyhemoglobin saturation of less than 90% for 2% or more of the total
sleep time were not eligible, owing to the severity of the
polysomnographic findings. Exclusion criteria included recurrent
tonsillitis, a z score based on the body-mass index (the weight in
kilograms divided by the square of the height in meters) of 3 or more,
and medication for attention deficit– hyperactivity disorder. Children
were randomly assigned to two arms of treatment: early AT within 4 weeks
after randomization or a strategy of
watchful waiting with supportive
care (WWSC).
The primary outcome of this post-hoc analysis was wheezing at 7-months
of follow-up after AT. Wheezing was divided in two groups: “no
wheezing” and “any wheezing”. The latter included rarely (less than
once a week), sometimes (1 to 2 times per week), frequently (3 to 4
times per week) and always or almost always (5 to 7 times per week).
“Any wheezing” was further divided according to the severity of
wheezing in three groups: frequent wheezing (sometimes, frequent, and
always), rarely wheezing, and no wheezing.