Quarterly Assessment of Short-Acting β₂-Adrenergic Agonist Use as a Predictor of Subsequent Health Care Use for Asthmatic Patients in the United States

Abstract

Purpose. An annual time frame for risk assessment may not account for the variable course of asthma. The purpose of this study was to determine whether excessive short-acting β₂-adrenergic agonist (SABA) dispensed quarterly was associated with asthma exacerbations in the subsequent quarter. Patients and Methods. This retrospective cohort analysis included 93,604 health plan members aged 6–56 years with ≥2 years of continuous enrollment (2003–2007), an asthma diagnosis, and asthma prescription claims. The amount of SABA dispensed in claims (metered-dose inhaler and nebulized) was converted to canister equivalents (CEs) in the first observation quarter and categorized as 0, 0.5–3, and ≥3 (excessive SABA use). Asthma exacerbation risk (hospitalization, emergency department [ED] visit, or oral corticosteroid [OCS] claim in the subsequent quarter) was assessed using logistic regression. Covariates used in the regression models were age, sex, geographic region, comorbidities, specialist consultation, asthma controller medication use, and asthma severity. Results. The cohort included 33,951 patients aged 6–17 years (36%) and 59,653 aged 18–56 years (64%); 64% had 0 SABA CE, and 5% had >3 SABA CEs. Compared with 0 CE, excessive SABA use (>3 CEs) was associated with an increased likelihood of hospitalization (adjusted odds ratio [OR]: 3.15, 95% confidence interval [CI]: 1.89–5.27) and an ED/urgent care (UC) visit (adjusted OR: 3.14, 95% CI: 2.32–4.28). Conclusion: The risk of an asthma exacerbation was associated with excessive SABA use in the previous quarter. Assessment of excessive SABA dispensed during a calendar quarter can be used to identify patients at increased exacerbation risk in the subsequent quarter.

Keywords :

• asthma control
• asthma exacerbation
• health services research
• outcomes research
• pharmacoepidemiology
• SABA utilization

Acknowledgments

The authors would like to thank Lauren Farmer of the Division of Clinical and Outcomes Research, Lovelace Respiratory Research Institute, for her assistance in the writing of the manuscript, Susan Berry, M.S.W., L.C.S.W., of the Division of Clinical and Outcomes Research, Lovelace Respiratory Research Institute, for her assistance in the preparation of the manuscript, and Anny Wu, Pharm.D., of Scientific Connexions (Newtown, Pennsylvania) for her assistance in editing the manuscript.