Cost sharing, family health care burden, and the use of specialty drugs for rheumatoid arthritis.

OBJECTIVES

To examine the impact of benefit generosity and household health care financial burden on the demand for specialty drugs in the treatment of rheumatoid arthritis (RA).

DATA SOURCES/STUDY SETTING: Enrollment, claims, and benefit design information for 35 large private employers during 2000-2005.

STUDY DESIGN

We estimated multivariate models of the effects of benefit generosity and household financial burden on initiation and continuation of biologic therapies.

DATA EXTRACTION METHODS

We defined initiation of biologic therapy as first-time use of etanercept, adalimumab, or infliximab, and we constructed an index of plan generosity based on coverage of biologic therapies in each plan. We estimated the household's burden by summing up the annual out-of-pocket (OOP) expenses of other family members.

PRINCIPAL FINDINGS

Benefit generosity affected both the likelihood of initiating a biologic and continuing drug therapy, although the effects were stronger for initiation. Initiation of a biologic was lower in households where other family members incurred high OOP expenses.

CONCLUSIONS

The use of biologic therapy for RA is sensitive to benefit generosity and household financial burden. The increasing use of coinsurance rates for specialty drugs (as under Medicare Part D) raises concern about adverse health consequences.