Most nocturnal asthma symptoms occur outside of exacerbations and associate with morbidity

Abstract

Background: Although nocturnal awakenings help categorize asthma severity and control, their clinical significance has not been thoroughly studied.

Objective: We sought to determine the clinical consequences of nocturnal asthma symptoms requiring albuterol (NASRAs) in children with mild-to-moderate persistent asthma outside of periods when oral corticosteroids were used for worsening asthma symptoms.

Methods: Two hundred eighty-five children aged 6 to 14 years with mild-to-moderate persistent asthma were randomized to receive one of 3 controller regimens and completed daily symptom diaries for 48 weeks. Diary responses were analyzed for the frequency and consequences of NASRAs.

Results: NASRAs occurred in 72.2% of participants at least once, and in 24.3% of participants, they occurred 13 or more times. The majority (81.3%) of nocturnal symptoms occurred outside of exacerbation periods and were associated the next day with the following events: albuterol use (56.9% of days preceded by nocturnal symptoms vs 18.1% of days not preceded by nocturnal symptoms; relative risk [RR], 2.3; 95% CI, 2.2-2.4), school absence (5.0% vs 0.3%; RR, 10.6; 95% CI, 7.8-14.4), and doctor contact (3.7% vs 0.2%; RR, 8.8; 95% CI, 6.1-12.5). Similar findings were noted during exacerbation periods (RRs of 1.7 for albuterol use, 5.5 for school absence, and 4.9 for doctor contacts). Nocturnal symptoms did not predict the onset of exacerbations.

Conclusion: Nocturnal symptoms requiring albuterol in children with mild-to-moderate persistent asthma receiving controller therapy occurred predominantly outside of exacerbation periods. Despite being poor predictors of exacerbations, they were associated with increases in albuterol use, school absences, and doctor contacts the day after nocturnal symptom occurrences.

Figure 1. NASRA occurrence during exacerbation periods

The horizontal axis is centered on the day prednisone treatment was initiated. For 21% of the asthma exacerbations which occurred during the course of the trial, a NASRA was reported the night before prednisone was initiated. The frequency of NASRA remained low until the third day prior to prednisone initiation and returned to pre-exacerbation levels within 5 days.