Impact of Out-of-Pocket Costs on Prescription Fills Among New Initiators of Biologic Therapies for Rheumatoid Arthritis

BACKGROUND: Biologic disease-modifying antirheumatic drug (DMARD) therapies are a mainstay of treatment for rheumatoid arthritis (RA), yet high member out-of-pocket (OOP) costs for such therapies may limit patient access to these therapies. OBJECTIVE: To understand whether there is a relationship between OOP costs and the initial fill and subsequent refills of biologic DMARD treatments for RA members. METHODS: Members of a national Medicare Advantage and Prescription Drug (MAPD) plan with an adjudicated (paid or reversed) claim for a biologic DMARD indicated for RA were identified from July 1, 2007, to December 31, 2012, and followed retrospectively. The first adjudicated claim date was the index date. Members were required 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. Low-income subsidy and Medicaid-Medicare dual-eligible patients were excluded. The analysis used multivariate regression models to examine associations between initial prescription (Rx) abandonment rates and OOP costs and factors influencing the refill of a biologic DMARD therapy based on pharmacy claims. RESULTS: The final sample size included 864 MAPD members with an adjudicated claim for a biologic DMARD. The majority were female (77.4%) and mean age was 63.5 years (SD = 10.9). Most (78%) had conventional nonbiologic DMARD utilization during pre-index. The overall initial abandonment rate was 18.2% for biologic DMARDs, ranging 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). ORs for abandonment rose 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, relative to OOP costs of ≤ $250.00 (all P < 0.0001). Meeting the catastrophic coverage limit and utilization of a specialty pharmacy for the index claim were both associated with a decreased likelihood of abandoning therapy (OR = 0.29 and OR = 0.14, respectively; both P < 0.05). Among the subset of 533 members with a paid claim, 82.4% had at least 1 refill post-index. The negative association between OOP cost and likelihood of refilling an Rx was highly significant (P < 0.0001). CONCLUSIONS: This study suggests that the higher the member OOP cost, the less likely an MAPD member is to initiate or refill a biologic DMARD therapy for RA. Further research is needed to understand reasons for initial Rx abandonment and lack of refills, including benefit design and adverse events.