Medication Adherence Among Adults With Comorbid Chronic Conditions Initiating Oral Anticancer Agent Therapy for...

Increased use of oral anticancer agents (OAAs) has empowered adults with multiple myeloma (MM) to manage their oncolytic therapy, but such a shift may result in issues with medication use, particularly among patients being concurrently treated for pre-existing, multiple chronic conditions.

This retrospective cohort study used 2013-2018 commercial and Medicare claims data to assess medication use in adults with MM. To be included, adults (18 years and older) must have been diagnosed with and had 2+ claims for an OAA, had continuous enrollment for 12 months before and after OAA initiation, and have been previously diagnosed with and had prescription fills for 2+ select chronic conditions. The proportion of days covered metric assessed medication adherence and was compared for 12 months before and after the OAA initiation by Wilcoxon signed-rank tests, McNemar's tests, and difference-in-differences models.

The mean OAA adherence in the first year of therapy was 58.3% (standard deviation: 24.5) and 65.1% (standard deviation: 27.01) for commercial and Medicare patients, respectively. Adherence and the proportion adherent (proportion of days covered ≥ 80%) to comorbid therapies generally declined in the first year after OAA initiation. Changes in medication use were particularly noticeable among those on antihypertensive therapy: adjusted analyses uncovered a 2.5% (Medicare) and 5.2% (commercial) difference in adherence to these medications between those initially adherent and nonadherent to OAA therapy (both P < .05).

Initiating OAA therapy in adults with MM may complicate an already complex treatment regimen, resulting in poor overall medication adherence in patients with multiple comorbid conditions.