Consumer cost sharing and use of biopharmaceuticals for rheumatoid arthritis.

OBJECTIVES To evaluate the effect of consumer cost sharing on use of physician-administered and patient self-administered specialty drugs for rheumatoid arthritis. DESIGN Multivariate statistical analysis of probability and use of physician-administered specialty drugs, patient self-injected specialty drugs, non-biologic disease-modifying anti-rheumatic drugs, and symptom relief drugs. Analyses were conducted for patients enrolling in preferred provider organization (PPO) plans and health maintenance organization (HMO) plans with different cost-sharing requirements, adjusted for patient demographics, health status, and geographical location. SETTING Professional, facility, and pharmaceutical claims for beneficiaries of CalPERS, the public employee insurance purchasing alliance in California, for 2008-2009. Consumer cost-sharing requirements were obtained for each type of drug and service for each type of insurance plan. RESULTS PPO insurance enrollees face substantially higher cost sharing for physician-administered specialty drugs, compared with HMO enrollees in CalPERS. PPO patients with rheumatoid arthritis are only half as likely as HMO enrollees to choose a physician-administered specialty drug (4.2% vs 9.3%) (P ≤.05), and use 25% less of the drugs if they use any ($10,356 vs $13,678) (P ≤.05). They are 30% more likely to use a self-administered specialty drug than are HMO enrollees (29.3% vs 22.1%) (P ≤.05), and use 35% more of the drugs if any ($16,015 vs $12,378) (P ≤.05). CONCLUSIONS Consumer cost sharing reduces the use of physician-administered specialty drugs for rheumatoid arthritis. The higher use of patient self-administered specialty drugs suggests that the disincentives for use of physician-administered drugs were offset by an increased incentive to use self-administered drugs.