PURPOSE: To assess the potential of the impairment domain components of the NHLBI asthma guidelines to predict future asthma exacerbations in patients with severe or difficult-to-treat asthma.
METHODS: Children aged 6-11 years (n=289) and adolescents/adults (n=2094) aged ≥12 years from TENOR with non-missing data at baseline and month 12 were included. Using impairment domain components, patients’ asthma was categorized into very poorly controlled (VPC), not well controlled (NWC), and well controlled (WC) at baseline. The effect of omitting each impairment domain component on classification into VPC and NWC groups was examined. Multivariable logistic regression, by age group, was used to predict risk of asthma exacerbation, defined as corticosteroid burst, emergency room visit, or overnight hospitalization at month 12. Analyses were performed with/without the Asthma Therapy Assessment Questionnaire (ATAQ) control survey in adolescents/adults.
RESULTS: The proportion of patients whose asthma control classification remained the same after omitting one impairment domain component was high (>90% for majority of components). In both age groups, an asthma exacerbation at baseline was the strongest independent predictor of exacerbation at month 12 (odds ratio [OR]: 2.94 in children; OR: 2.93 in adolescents/adults; OR: 3.17 when ATAQ excluded, p<.001 for all). Children with VPC asthma based on short-acting beta2-agonist (SABA) use had a two-fold increased risk of exacerbation (OR: 2.03, p=0.011) compared with children without VPC asthma. Adolescents/adults with NWC or VPC asthma based on SABA use (OR: 1.49), lung function (OR: 1.66), or ATAQ (OR: 1.94) were also at increased risk of exacerbations (p<.001 for all). When ATAQ was excluded, daytime symptoms and normal activity were also significantly associated with asthma exacerbations.
CONCLUSION: Although not all impairment domain components may be necessary to classify asthma control accurately, certain individual components are important for predicting asthma exacerbations. The ATAQ alone may reasonably capture significant components needed to predict exacerbations.
CLINICAL IMPLICATIONS: Individual impairment domain components are important for predicting future asthma exacerbations. When needed, the ATAQ may be used to predict exacerbations.
DISCLOSURE: Bradley Chipps, Consultant fee, speaker bureau, advisory committee, etc. R.S. Zeiger has consultant arrangements with AstraZeneca, Aerocrine, Genentech, GlaxoSmithKline, MedImmune, Merck, and Schering-Plough and receives grant/research support from AstraZeneca, Aerocrine, Genentech, GlaxoSmithKline, and Merck.; Other This study was supported by Genentech, Inc., South San Francisco, CA and Novartis Pharmaceuticals Inc., East Hanover, NJ.; No Product/Research Disclosure Information