The rate per year of asthma episodes culminating in an asthma attack for each of the 3 treatment groups. Asthma attacks were defined as respiratory symptoms requiring healthcare resource utilization (HRU), which comprised unscheduled visits to a physician or emergency department, treatment with corticosteroids (oral, rectal, or inhaled), or hospitalization. Each day during an episode, the patient's legal guardian recorded all the HRU that was required specifically for breathing problems.

Each day during an asthma episode, the patient's legal guardian was asked to rate each of the symptoms of wheeze and difficulty breathing on a 6-point scale (Scale 0 (best) to 5 (worst)). The average of the individual symptom scores on each of the 3 days prior to an asthma attack was reported. If a patient had multiple episodes during 1 year, the symptom scores were averaged across all the episodes.

Each day during an asthma episode, the patient's legal guardian was asked to rate each of the symptoms of Wheeze, Difficulty Breathing, Interference with Activity, and Daytime Cough on a 6-point scale (Scale 0 (best) to 5 (worst)). The average of the individual symptom scores on each of the 12 days of intermittent treatment for an episode (before the first attack) was reported. If a patient had multiple episodes over 1 year, the symptom scores were averaged across all the episodes.