As readers of Medical Care are no doubt aware, prescription drug expenditures for Medicare beneficiaries are high – nearly $90 billion in 2012. There is some evidence that Medicare Part D has reduced financial burdens, at least among some beneficiaries, but recent surveys suggest that around 4.4% of individuals ages 65 and older (including those not on Medicare) experienced out-of-pocket cost burdens that interfered with adherence to providers’ treatment recommendations.
In their recent Medical Care article, Burcu and colleagues discussed the convergent validity and tested the factor structure of several questions about cost-related medication burden in the Medicare Current Beneficiary Survey (MCBS). They found 2 distinct but related constructs: (1) cost-related medication nonadherence, and (2) drug-shopping behaviors. Interestingly, a question about whether beneficiaries had reduced spending on basic needs was closely related to the measures of cost-related nonadherence and loaded strongly on that factor.
Cost-related nonadherence was measured by:
- taking smaller doses
- skipping doses
- deciding not to fill or refill a prescription
- delaying filling or refilling a prescription, and/or
- spending less on basic needs to have more money for medication.
Drug-shopping behavior was measured by:
- asking for generic version of prescription
- obtaining/asking for medication samples
- comparing prices/shopping for the best prices for medications, and/or
- purchasing medications from another country.
While the main 4 questions used to measure cost-related nonadherence have been validated previously, Burcu and colleagues are the first to have also looked robustly at the factor structure including items about coping mechanisms such as shopping behavior and and spending on basic needs. In the confirmatory factor analysis, the nonadherence factor performed well both with and without the items about spending on basic needs. Another item commonly used in studies of nonadherence–whether medications were purchased by mail or internet–did not load significantly on either factor and was dropped. The authors point out several potential reasons for this, including: home-bound individuals might be more likely to use these methods regardless of cost; some plans provide incentives for using these methods; and the question does not specifically ask about the behavior as a mechanism to reduce costs.
The results of this article are timely, as the Affordable Care Act (ACA) contains provisions to reduce the out-of-pocket costs that Medicare beneficiaries pay for medications. By validating the MCBS questions about nonadherence and suggesting a 2-factor approach, Burcu and colleagues have made the task of evaluating the ACA’s impact on nonadherence easier. They’ve also provided a way to increase the comparability of studies about self-reported cost-related nonadherence in the Medicare population.
Jess Williams