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Impact of Cost‐Sharing Increases on Continuity of Specialty Drug Use: A Quasi‐Experimental Study
Author(s) -
Li Pengxiang,
Hu Tianyan,
Yu Xinyan,
Chahin Salim,
Dahodwala Nabila,
Blum Marissa,
Pettit Amy R.,
Doshi Jalpa A.
Publication year - 2018
Publication title -
health services research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.706
H-Index - 121
eISSN - 1475-6773
pISSN - 0017-9124
DOI - 10.1111/1475-6773.12744
Subject(s) - cost sharing , specialty , medicine , medicare part d , copayment , family medicine , prescription drug , medical prescription , health insurance , nursing , health care , economics , economic growth
Objective To examine the impact of cost‐sharing increases on continuity of specialty drug use in Medicare beneficiaries with multiple sclerosis ( MS ) or rheumatoid arthritis ( RA ). Data Sources/Study Setting Five percent Medicare claims data (2007–2010). Study Design Quasi‐experimental study examining changes in specialty drug use among a group of Medicare Part D beneficiaries without low‐income subsidies (non‐ LIS ) 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 ( LIS ), 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. Principal Findings Relative to the LIS group, the non‐ LIS 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 ( MS , absolute increase = 10.1 percent, OR = 1.61, 95% CI 1.19–2.17; RA , absolute increase = 21.9 percent, OR = 2.75, 95% CI 2.15–3.51). The increase in Part D treatment gaps was not offset by increased Part B specialty drug use. Conclusions Cost‐sharing increases due to specialty tier‐level cost sharing were associated with interruptions in MS and RA specialty drug treatments.