Impact of Generic-Only Drug Benefits on Inhaled Corticosteroid Use in Medicare Patients with Asthma
Author Information
Author(s): Vicki Fung, Ira B. Tager, Richard Brand, Joseph P. Newhouse, John Hsu
Primary Institution: Kaiser Permanente Division of Research
Hypothesis
How does the introduction of generic-only drug coverage affect the use of inhaled corticosteroids among Medicare patients with asthma?
Conclusion
Patients reduced their inhaled corticosteroid use in response to losing drug coverage, but switching to lower-cost options helped mitigate this reduction.
Supporting Evidence
- 74% of patients switched to generic-only coverage, leading to reduced inhaled corticosteroid use.
- Patients using higher-cost inhaled corticosteroids were more likely to switch to lower-cost options under restricted coverage.
- Restricted coverage was associated with a decrease in inhaled corticosteroid use among patients who did not switch.
Takeaway
When patients had to pay more for their asthma medicine because of insurance changes, they used it less. But if they switched to a cheaper version, they didn't stop using it as much.
Methodology
The study used linear difference-in-difference models to analyze changes in inhaled corticosteroid use before and after the introduction of generic-only coverage.
Potential Biases
Potential bias due to unmeasured confounding factors despite adjustments for many socio-demographic and clinical characteristics.
Limitations
The study was non-randomized, which may introduce unmeasured differences between groups.
Participant Demographics
Participants were Medicare Advantage beneficiaries aged 65 and older with asthma, with a mix of gender and race/ethnicity.
Statistical Information
P-Value
0.001
Confidence Interval
95% CI: -25.0 to -6.0
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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