National Asthma Education and Prevention Program severity classification as a measure of disease burden in children with acute asthma

OBJECTIVE. To examine the association between the National Asthma Education and Prevention Program (NAEPP) severity classification and other measures of burden of disease in children with acute asthma. METHODS. We performed a cross-sectional study of 750 children < 18 years of age with a physician diagnosis of asthma and treated in an emergency department (ED) for acute asthma exacerbation. Subjects were assigned to 1 of 4 levels of severity ( mild intermittent, mild persistent, moderate persistent, or severe persistent). Assignments followed 3 methods: the report of symptom frequency alone ( standard method); symptom frequency and reported controller-medication use ( modified method); or the additive modified method in which the symptom frequency and reported controller-medication use were assigned numeric values and a score was calculated. An asthma-specific quality-of-life score was calculated by using the Integrated Therapeutics Group Child Asthma Short Form (ITG-CASF). The number of ED visits and hospital admissions for asthma over the previous 12 months was collected also. Differences between severity groups were compared with analysis of variance, and the proportion of variance explained (r(2)) was calculated. RESULTS. Using the standard classification method, 55% of subjects had mild intermittent asthma, 21% had mild persistent asthma, 14% had moderate persistent asthma, and 10% had severe persistent asthma. Among those classified as having mild intermittent asthma by symptoms alone, 22% were reclassified as having persistent asthma when controller medications were accounted for. With all 3 scoring methods, mean ITG-CASF scores decreased significantly with each increasing level of severity. However, the magnitude of this association was modest. There was a significant but limited association between severity level and mean number of ED visits and hospitalizations. CONCLUSION. NAEPP severity classification alone provides an incomplete picture of the burden of disease in children with asthma.