To examine the impact of cost‐sharing increases on continuity of specialty drug use in Medicare beneficiaries with multiple sclerosis () or rheumatoid arthritis ().
Data Sources/Study Setting
Five percent Medicare claims data (2007–2010).
Quasi‐experimental study examining changes in specialty drug use among a group of Medicare Part D beneficiaries without low‐income subsidies (non‐) as they transitioned from a 5 percent cost‐sharing preperiod to a ≥25 percent cost‐sharing postperiod, as compared to changes among a disease‐matched contemporaneous control group of patients eligible for full low‐income subsidies (), who faced minor cost sharing (≤$6.30 copayment) in both the pre‐ and postperiods.
Data Collection/Extraction Methods
Key variables were extracted from Medicare data.
Relative to the group, the non‐ group had a greater increase in incidence of 30‐day continuous gaps in any Part D treatment from the lower cost‐sharing period to the higher cost‐sharing period (, absolute increase = 10.1 percent, = 1.61, 95% 1.19–2.17; , absolute increase = 21.9 percent, = 2.75, 95% 2.15–3.51). The increase in Part D treatment gaps was not offset by increased Part B specialty drug use.
Cost‐sharing increases due to specialty tier‐level cost sharing were associated with interruptions in and specialty drug treatments.
