To our knowledge, this is the first study to link patient beliefs or communication about generic drugs with actual medication use, offering payors and policymakers insight into the expected benefits of educational campaigns to influence such perceptions. We found that health beliefs about generic drugs across a number of domains were associated with generic use. When evaluated individually, more positive responses in all domains of beliefs and communication about generics (general perceptions, generic safety/efficacy, generic value, comfort with generic substitution, and communicating with providers) were associated with greater generic drug use. However, after fully adjusting for all of these beliefs and communication, it was only the most actionable items—talking with providers about generics and comfort with generic substitution—that maintained significant relationships with actual generic drug use.
Empirical data is needed to guide the development of strategies to improve rational and cost-effective prescribing. Although numerous studies demonstrate that communication between patients and both pharmacists and physicians about new prescriptions written are incomplete27,28
and cost is rarely communicated,29–31
our results suggest that patients most comfortable with generic substitution and who communicate with providers about generics are more likely to use generics. Simply holding positive preferences for generic medications may exert little influence on the prescribing process. If insurers or policymakers hope to increase generic drug use, educational campaigns may be most effective if they concentrate on these 2 loci in which patients can most directly influence the medication they receive.
We are unable to definitively discriminate whether more positive beliefs and communication about generic drug use cause increased generic drug use, or whether patients who use more generics tend to have more positive views about them. However, if even part of the relationship between beliefs and actual use is causal, then educational campaigns that affect preferences or communication about generics would have a meaningful influence on drug use and overall drug spending. Recent estimates indicate that every 1% increase in generic drug use would reduce overall spending on prescription drugs in the United States by $4 billion annually.32
An educational campaign targeted at improving communication with providers about generics or comfort with generic substitution could reduce overall drug spending by billions of dollars annually in the United States if it even modestly affects generic drug use. As an important national purchaser of prescription drugs, Medicare may consider educating seniors about these issues.
Such educational interventions may also improve adherence to chronic medications. Most patients in the United States are enrolled in tiered benefit plans that charge greater copayments for branded drugs33
and recent findings suggest that patients enrolled in tiered benefit plans are most adherent to chronic medications when prescribed generic medications.34
To perform this analysis, we created a unique data set that linked beliefs to actual medication use. Few opportunities to examine the relationship between beliefs and actual medication use exist, and have been focused on understanding how patient requests for antibiotics or advertised medications affect prescribing behavior.35,36
Research designs such as ours may be useful as we evaluate the effects of prescription drug policies on medication use. Including beliefs and communication in models assessing medication use can help to clarify policy solutions to optimize the value of prescription drug care. Moreover, such designs may reveal unforeseen obstacles in policy development.
In the adjusted models, patient-level characteristics had less influence on generic drug use than seen in previous studies.14,15
However, previous studies did not account for patient beliefs or communication. Correlations have previously been reported between patient sociodemographic characteristics and preferences.37
The relationships identified in previous studies between patient characteristics and generic drug use were likely mediated by beliefs and communication with providers about generic drugs. In our adjusted analyses, few patient-level characteristics were significantly associated with generic drug use after controlling for patient-level beliefs and communication.
The response rate for this survey was less than 50%, although measured characteristics of respondents and nonrespondents were similar. Nonetheless, caution is warranted when generalizing these findings more broadly. In addition, we sampled only commercially-insured patients with pharmacy benefit coverage, and cannot comment on patients who either have no coverage or state- or federally-sponsored coverage.
Our outcome variable was influenced by drug mix. Patients may have had low generic fill rates because they were using single-source branded medications where no generic alternative was available. That said, the overall percentage of generic drug use in this sample was greater than 60%, consistent with national estimates.38
In another study evaluating the population from which our sample was randomly selected, the majority of branded drug use occurred in classes where generics were available (eg, statins or antihypertensives) and therapeutic interchange for a generic was a possibility.38
Nonetheless, if patients with specific characteristics and beliefs tended to fill only single-source medications with no generic therapeutic alternative, this could have introduced bias into our design. Including classes of medications with no generic alternative likely led to conservative estimates of the strength of relationship between beliefs about generics and actual generic drug use.
We did not account for days supply of prescriptions filled when calculating our outcome variable. We did not have access to this variable in our analytic dataset. Although we do not expect this to have introduced significant bias into our analysis, we may have missed an opportunity to explore whether use of mail-order pharmacies, which generally provide 3-month supplies, mediate some of the differences seen in generic fill rates in patients with varying beliefs and communication about generic drugs.
In addition, the strength of the relationship between general preferences for generics may have been moderated in our fully adjusted model by collinearity of predictor variables. However, unidimensional scales were identified using exploratory factor analysis, limiting the extent of collinearity between the factors. Additionally, we found stronger relationships between the 2 factors found to remain significant in the fully adjusted model than the other factors when factors were evaluated individually.
These findings point to strategies which health plans or policymakers may choose to educate patients about features of the process of choosing and filling prescriptions when trying to encourage rational medication use. In our consumer-driven healthcare system, patients and doctors frequently have difficulty navigating complex benefit designs and identifying the most cost-effective options.31,39
Educational campaigns that focus on enhancing the frequency that patients talk to their physicians and pharmacists about generic medications, and improve comfort with those discussions, may meaningfully influence generic drug use. Similarly, interventions that provide accessible information about generic options for patients’ medical conditions, increase opportunities for generic substitution, and that demystify the generic substitution process may be influential. Although there is little existing evidence to guide the development of such interventions, efforts to empower patients to actively participate in the medication selection process may have the greatest effect on actual drug use.