Table 4. Participants With Adverse Events Related to the Study, by Randomized Group and According to Seriousness^a.

	No. of participants
	Early adenotonsillectomy (n = 231)		Watchful waiting (n = 227)
	Serious	Nonserious	Serious	Nonserious
Adverse events related to adenotonsillectomyb
Postoperative pain		11
Postoperative bleeding	5	8	1
Dehydration		3
Aspiration pneumonia		1
Adverse events related to other study procedurec
Hives (allergy to tape used in PSG)		1
Vomiting (immediately following blood draw)		1

Abbreviation: PSG, polysomnography.

^a Adverse events were defined as any unfavorable or unintended sign, symptom, or disease occurring in a participant at any stage following consent (see Supplement 1 and Supplement 2).

^b The following events were prespecified as not requiring reporting: intraoperative blood loss 7 mL/kg or less; postoperative pain, hoarseness, or difficulty swallowing lasting less than 21 days and not requiring intravenous hydration or unscheduled evaluation or treatment; postoperative blood-tinged oral or nasal secretions lasting less than 72 hours; velopharyngeal insufficiency lasting less than 2 months and not requiring evaluation or treatment.

^c The following events were prespecified as not requiring reporting: skin irritation associated with adhesives used in PSGs lasting less than 2 days; temporary depigmentation under areas of PSG sensor attachment lasting less than 1 month; poor sleep during PSG; temporary pain at the site of the phlebotomy lasting less than 48 hours; bleeding or bruising at the site of the phlebotomy not requiring evaluation or treatment; anxiety surrounding behavioral testing not requiring psychiatric attention.