Date of Graduation


Document Type


Degree Type



School of Pharmacy


Pharmaceutical Systems and Policy

Committee Chair

Usha Sambamoorthi

Committee Co-Chair

Nilanjana Dwibedi

Committee Member

Traci J. LeMasters

Committee Member

Megan Adelman

Committee Member

S. Suresh Madhavan


In many older adults, asthma and chronic obstructive pulmonary disease (COPD) coexist as “Asthma-COPD overlap” (ACO). This dissertation pursued three Aims: 1) estimate the economic burden of ACO and its contributory factors; 2) evaluate the association of ACO to “cost-related medication nonadherence” (CRN); and 3) identify adherence trajectory patterns and examine the impact of initial maintenance therapies (IMT) type (inhaled corticosteroids monotherapy (ICS) vs. fixed-dose combination of ICS and long-acting beta agonist (ICS/LABA)) on adherence trajectory patterns among older adults Medicare Beneficiaries. The first and second Aims were cross-sectional studies by using Medicare Current Beneficiary Survey data. For the third Aim, we used a longitudinal retrospective cohort design, using 10% sample of Optum’s Deidentified Clinformatics®. In this study, older adults with ACO had nearly four times higher average total healthcare expenditures compared to those no-asthma no-COPD (NANC). The higher number of medications and fragmented care were the leading contributors of the economic burden. Moreover, compared to older adults with NANC, those with ACO were more likely to report any CRN. This association was highly dependent on number of medications. In addition, we identified four medication adherence trajectories to IMT among older adults with ACO. Those who using ICS/LABA were less likely to have “persistent low adherence” (Adjusted Odds Ratio= 0.38). In summary, these findings highlight the need to reduce the economic burden and improve medication adherence among older adults with ACO. Additionally, using ICS/LABA for IMT may improve adherence to IMT among older adults with ACO.

Embargo Reason

Publication Pending