Tiered Co-payments and Cost-Related Medication Underuse?
- Presenter:
Mon June 5, 2006 9:30-10:45 Room Alumni Lounge
Introduction Many insurance plans use tiered co-payments, in which patients pay less for generic medications than for branded prescriptions, to encourage the use of generic medications. However, co-payments may force some patients to forgo prescription drugs due to costs. Research indicates that approximately 20% of adults with a chronic illness will underuse prescription drugs due to cost pressures. With cost-sharing on the rise, many decision makers are concerned because underuse of medication has been linked to worse health outcomes and to greater rates of hospitalization. In this study, we analyze how tiered co-payments are associated with medication underuse.
Methods We fielded a national survey of chronically ill adults over age 50 (n=4085). Respondents reported whether they had been given a prescription for each of 16 chronic health problems. On a condition-by-condition basis, participants were asked: “In the past 12 months, have you ever taken less of this medication than prescribed by your doctor because of the cost?” If they said yes, they were asked whether they (1) did not fill a prescription at all, (2) took fewer pills or a smaller dose, (3) put off or postponed getting a prescription filled, (4) used herbal medicines or vitamins when they felt sick rather than take their prescription medication, and (5) took the medication less frequently than recommended to ‘stretch out’ the time before getting a refill. For each of these five questions, responses were collecting using a 5-point ordinal scale: never, less than every two or three months, about every two or three months, at least once a month, at least once a week. We used linear probability models to estimate the probability of underuse as a function of co-payments among those with tiered co-payments (n=2771). We created dummy variables for co-payments: <$5, >$5 and <=$15, >$15 and <=$50, or >$50, do not know, or are not sure. In the multivariate analyses, we controlled for age, gender, income, and chronic conditions, and we used sampling weights and corrected the standard errors for clustering.
Results Cost-related underuse was more consistently associated with higher co-payments for generic medications than for branded medications, suggesting that people were less-price sensitive to their branded medications. The association between co-payments and cost-related underuse was strongest for not filling a prescription and postponing the filling of a prescription; the association was considerably weaker for stretching out the dose, taking fewer doses or substituting herbal medications.
Conclusions A substantial minority responds to co-payments by underusing their medication, and the effect is greatest at the cash register where people either do not fill the prescription or postpone filling the prescription. Although underuse is associated with co-payments, the effects are not the same for generic and brand name medication. People were more likely to forego medication when prescribed a generic than a brand name medication. Given that most patients do not talk to their clinician about medication underuse, clinicians need to explain the use of generic medications to their patients so that patients do not always equate value with price.
