Most Nocturnal Asthma Symptoms Occur Outside of Exacerbations and Associate with Morbidity

Abstract

RATIONALE: Although nocturnal awakenings help categorize asthma severity and control, their clinical significance has not been thoroughly studied. We sought to determine the clinical consequences of nocturnal asthma symptom(s) requiring albuterol in children with mild-to-moderate persistent asthma.METHODS: 285 children ages 6 to 14 years with mild-to-moderate persistent asthma were randomized to receive one of three controller regimens and completed daily symptom diaries for 48 weeks. Diary responses were analyzed for the frequency and consequences of nocturnal asthma symptoms requiring albuterol.RESULTS: Nocturnal asthma symptoms requiring albuterol occurred in 72.2% of participants at least once and in 24.3% of participants 13 times or more. 81% 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 versus 18.1% of days not preceded by nocturnal symptoms; Relative Risk (RR)=2.3; 95% CI:2.2, 2.4], school absence (5.0% versus 0.3%; RR=10.6; 95% CI:7.8, 14.4), and doctor contact (3.7% versus 0.2%; RR=8.8; 95% CI:6.1, 12.5). Relative risks for these morbidity factors were similar during exacerbation periods (RR=1.7 for albuterol use, 5.5 for school absence, and 4.9 for doctor contact). Nocturnal symptoms did not predict the onset of an exacerbation.CONCLUSIONS: 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. RATIONALE: Although nocturnal awakenings help categorize asthma severity and control, their clinical significance has not been thoroughly studied. We sought to determine the clinical consequences of nocturnal asthma symptom(s) requiring albuterol in children with mild-to-moderate persistent asthma. METHODS: 285 children ages 6 to 14 years with mild-to-moderate persistent asthma were randomized to receive one of three controller regimens and completed daily symptom diaries for 48 weeks. Diary responses were analyzed for the frequency and consequences of nocturnal asthma symptoms requiring albuterol. RESULTS: Nocturnal asthma symptoms requiring albuterol occurred in 72.2% of participants at least once and in 24.3% of participants 13 times or more. 81% 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 versus 18.1% of days not preceded by nocturnal symptoms; Relative Risk (RR)=2.3; 95% CI:2.2, 2.4], school absence (5.0% versus 0.3%; RR=10.6; 95% CI:7.8, 14.4), and doctor contact (3.7% versus 0.2%; RR=8.8; 95% CI:6.1, 12.5). Relative risks for these morbidity factors were similar during exacerbation periods (RR=1.7 for albuterol use, 5.5 for school absence, and 4.9 for doctor contact). Nocturnal symptoms did not predict the onset of an exacerbation. CONCLUSIONS: 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.