Study Results on Asthma Medication Adherence

By Sudhanshu Bansal and Sumeet Vashishta

11 June 2018

Practical Analytic Approaches to Healthcare Challenges

Asthma accounted for 3,651 deaths, 2 million emergency department (ED) visits, and about 11 million physician office visits for 2014 in United States (US).[i] The estimated total cost of asthma, including medical expenses, loss of productivity resulting from missed work days, and premature death, was $56 billion in 2007.[ii] Daily long-term control therapy is recommended for patients who have persistent asthma to reduce airway inflammation, control chronic symptoms, and prevent acute asthma attacks.[iii], [iv] Studies have shown that non-adherence to asthma control medications leads to an increase in exacerbations of asthma and subsequent hospitalizations[v], [vi]

To explore the impact of adherence to controller medications on utilization of healthcare services, Milliman conducted an analysis on a large database using MedInsight, Milliman’s healthcare analytics platform. The analysis targeted MARA (Milliman Advanced Risk Adjuster) adjusted utilization of emergency department services related to asthma and any diagnosis (all cause) in members with persistent asthma. The results were compared among three different groups based on adherence to controller medications (adherence below 50 percent, 50-75 percent, and above 75 percent).


  1. A statistically significant inverse correlation was found between the adherence rate (proportion of days covered (PDC)) and the number of ED visits.
  2. Asthmatic members enrolled with Medicare having adherence rate above 75 percent had a higher cost utilization as compared to below 50 and 50-75 percent. To some extent this could be explained by the fact that the members with adherence rate above 75 percent had a high comorbidity risk score as indicated by MARA.
  3. Asthmatic members enrolled with Medicaid had the highest overall ED utilization amongst all payer types.

Males generally had a higher ED utilization as compared to females.



Although analysis was based on administrative data, the statistical significance of the results highlights adherence to asthma controller medications as a target for interventions to reduce utilization and improve health outcomes for members with asthma.

[i] Centers for Disease Control and Prevention. Asthma Facts—National Center for Health Statistics, 2014. Available at:

[ii] Barnett SBL, Nurmagambetov TA. Costs of asthma in the United States: 2002–2007. J Allergy Clin Immunol 2011; 127(1): 145–52. Available at:

[iii] National Asthma Education and Prevention Program Expert Panel Report 3, 2007. Guidelines for the diagnosis and management of asthma.

[iv] Centers for Disease Control and Prevention. Asthma Stats. Use of long-term control medication among persons with active asthma. Available at:

[v] Piecoro LT, et al. Asthma Prevalence, Cost, and Adherence with Expert Guidelines on the Utilization of Health Care Services and Costs in a State Medicaid Population. Health Services Research. 2001; 36(2): 357-71. Available at:

[vi] Stern L, et al. Medication compliance and disease exacerbation in patients with asthma: a retrospective study of managed care data. Ann Allergy Asthma Immunol. 2006; 97(3): 402-8. Available at:

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