Out-of-Pocket Costs Influence Refill Rates for Rheumatoid Arthritis Drugs

Out-of-pocket spending has significant impact on prescription drug adherence in the treatment of RA through Medicare Advantage and Prescription Drug plan.

A recent study found the higher the out-of-pocket (OOP) costs, the less likely members of the Medicare Advantage and Prescription Drug (MAPD) plan will initiate or refill a biologic disease-modifying antirheumatic drug (DMARD) therapy for rheumatoid arthritis (RA).

During the study, published in the Journal of Managed Care & Specialty Pharmacy, researchers examined members of the national MAPD plan from July 1, 2007, to December 31, 2012, with a paid or adjudicated claim for a biologic DMARD for RA.

The first adjudicated claim date required members to have 180 days of continuous enrollment pre- and post-index, and ≥ 1 diagnosis for RA (ICD-9-CM: 714.0 or 714.2) during pre-index or ≤ 30 days post-index.

Multivariate regression models were also used to analyze the associations between initial prescription abandonment rates and the OOP costs, as well as factors that influence the refill of biologic DMARD therapy based off pharmacy claims.

The results of the study, which included a sample size of 864 MAPD members with adjudicated claim for biologic DMARD, showed 78% of members had conventional non-biologic DMARD utilization during pre-index.

The overall initial abandonment rate was 18.2% for biologic DMARDs, which ranged from 1.3% for the lowest OOP cost group ($0-$250) to 32.7% for the highest OOP cost group (> $550; P < 0.0001 for Cochran-Armitage trend test).

Furthermore, ORs for abandonment increased from 18.4 to 32.7 to 41.2 for OOP costs of $250.01-$400.00, $400.01-$550.00, and > $550.00 respectively. This was relative to OOP costs of ≤ $250.00 (all P < 0.0001).

When the catastrophic coverage limit and utilization of a specialty pharmacy for the index claim was met, an association was found with a decreased likelihood of abandoning therapy (OR = 0.29 and OR = 0.14, respectively; both P < 0.05).

Among 533 members with a paid claim, approximately 82.4% had at least 1 refill post-index. There was also a highly significant negative association between OOP cost and likelihood of refilling an Rx (P < 0.0001).

Within the study, 77% of member were women, and had a mean age of 63.5-years-old (SD = 10.9).

Although the study revealed an association, further research still needs to be done in order to determine the reason for initial Rx abandonment and lack of refills, which includes benefit design and adverse events.

“While there has been an increase in the availability of biologic DMARDs for the treatment of RA, this study found an overall abandonment rate of 18.2% for members initiating such therapies,” the authors wrote. “Furthermore, we observed a correlation between the member’s OOP cost of the initial prescription and the likelihood the prescription would be abandoned: the higher the OOP cost, the greater the number of abandoned prescriptions.”