Table 1.

Features of the included studies.

Study feature	PEAK	AIMS	MIST	APRIL	INFANT
Years conducted	2001–2005	2004	2008–2010	2011–2015	2013–2015
Participants enrolled	285	238	278	607	300
Age of participants	24–48 months	12–59 months	12–53 months	12–71 months	12–59 months
Positive Modified Asthma Predictive Index1 required	Yes	No	Yes	No	No
Additional requirements in the past year	None	≥2 clinically significant wheezing exacerbations2	≥1 clinically significant wheezing exacerbation2	≥2 clinically significant wheezing exacerbations2	Uncontrolled asthma3
Study design	Parallel arm	Parallel arm	Parallel arm	Parallel arm	Cross-over
Run-in period	4 weeks	2 weeks	2 weeks	2–4 weeks	2–8 weeks
Run-in medication4	Placebo	No medication	Placebo	No medication	Placebo or openlabel ICS or LTRA
Treatment arm duration	104 weeks	52 weeks	52 weeks	52–78 weeks	16 weeks
Treatment arm interventions	Daily ICS Placebo	Intermittent ICS5 Intermittent LTRA5 Placebo	Daily ICS Intermittent ICS5	Azithromycin5 Placebo	Daily ICS Daily LTRA As-needed ICS

¹Defined as frequent wheezing (at least 4 episodes in the previous year) and either 1 major risk factor (parental history of asthma, personal history of atopic dermatitis, or aeroallergen sensitization) or 2 of 3 minor risk factors (peripheral blood eosinophilia ≥4%, 527 wheezing without colds, or allergic sensitization to foods)

²Defined as a wheezing episode necessitating an urgent care visit, hospitalization, or systemic corticosteroids

³Defined as symptoms >2 days per week (previous 2 weeks), nighttime awakening from asthma at least once (previous 4 weeks), ≥4 wheezing episodes within the past year, or ≥2 exacerbations requiring systemic corticosteroids in the preceding 6 months.

⁴Open-label albuterol sulfate was permitted during the run-in for each study

⁵Administered only during respiratory tract illnesses