Study: Increased Cost Sharing Can Lead to Medication Non-Adherence

The higher cost-sharing, the worse medication adherence is. This is the finding of a literature review published in the April 2022 issue of the Journal of Managed Care + Specialty Pharmacy.

The review, sponsored by Xcenda and the National Pharmaceutical Council, aimed to assess the relationship and factors associated with cost-sharing and medication adherence, clinical outcomes, healthcare resource utilization, and costs.

Reviewers did an assessment of 79 articles published between January 2010 and August 2020. Most studies, 71, reported the relationship between cost-sharing and treatment adherence, persistence and/or discontinuation; 16 reported data on cost-sharing and healthcare resource utilization or medication initiation, 11 on cost-sharing and healthcare costs, and 6 on cost-sharing and clinical outcomes.

The majority of publications found that increased cost-sharing was associated with worse adherence (84% of studies), persistence (79% of studies), or discontinuation (58% of studies). “When taken together, the included studies appear to suggest not only that increased cost-sharing is associated with decreased adherence but also that there is a ‘dose-response’ relationship, in which larger differences in cost-sharing were associated with worse adherence,” the reviewers wrote.

They found that the relationship between cost-sharing and adherence appeared to be stronger in patients are being treated for cardiovascular disease, compared with patients receiving oncology or diabetes treatment.

The reviewers noted the outcome definitions varied, making comparisons across publications difficult. Additionally, they said the association between cost-sharing and outcomes may be affected by the specific health condition a patient has, by insurance, or by patient characteristics, including income, health status, and race and ethnicity.

“We found a consistent inverse relationship between cost-sharing and worse adherence across many studies. Higher cost-sharing was consistently associated with lower adherence to prescribed medication. The association persisted regardless of the condition/patient population under study or type of cost-sharing (eg, copays, coinsurance, deductibles). The aggregate data also suggested that larger increases in cost-sharing were associated with worse adherence. The aggregate data suggest that increased cost-sharing may be associated with decreased outpatient visits but increased hospitalizations and no association with emergency department visits,” they wrote.