To examine the impact of cost‐sharing increases on continuity of specialty drug use in Medicare beneficiaries with multiple sclerosis () or rheumatoid arthritis ().
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 Sources/Study Setting
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.
Data Collection/Extraction Methods