ArticleBMC health services research2019
Can income-based co-payment rates improve disparity? The case of the choice between brand-name and generic drugs.
Article in BMC health services research, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 7 papers.
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Who cites it
7 citing papers in PubMed.
- Effect of Pharmacist-Led Educational Intervention on Switching to Generic Medicine Among Patients Using Brand-Name Medicines in Japan.Pharmacy (Basel, Switzerland) · 2026Article
- Knowledge, attitudes, and practices toward premature rupture of membranes among pregnant women and their associated factors: A study at Beijing friendship hospital, Beijing, China.Preventive medicine reports · 2026Article
- Choice intention for the national volume-based procurement drug and its associated factors: a cross-sectional study on patients with late-life depression in China.BMC psychiatry · 2024Article
- Promoting generic drug usage in Japan: correlation between generic drug usage and monthly personal income.Journal of pharmaceutical policy and practice · 2023Article
- Impact of differential copayment on patient healthcare choice: evidence from South Korean National Cohort Study.BMJ open · 2021Article
- Study of Factors to Increase the Usage Rate of Generic Drugs in Platelet Aggregation Inhibitors.Inquiry : a journal of medical care organization, provision and financingArticle
- Copayment Adjustments Under Bundled and Two-Tiered Pricing: Welfare Implications for Outpatient Care in Taiwanese Hospitals.Inquiry : a journal of medical care organization, provision and financingArticle
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Authors and funding
5 authors.
Funding
Abstract
backgroundHigher income population tend to prefer brand-name to generic drugs, which may cause disparity in access to brand-name drugs among income groups. A potential policy that can resolve such disparity is imposing a greater co-payment rate on high-income enrollees. However, the effects of such policy are unknown. We examined how patients' choice between brand-name and generic drugs are affected by the unique income-based co-payment rates in Japan; 10% for general enrollees and 30% for those with high income among the elderly aged 75 and over.
methodsWe drew on cross-sectional price variation among commonly prescribed 311 drugs using health insurance claims data from a large prefecture in Japan between October 2013 and September 2014 to identify between-income-group differences in responses to differentiated payments.
resultsRunning 311 multivariate logistic regression models controlling individual demographics, the median estimate indicated that high-income group was 3% (odds ratio = 0.97) less likely to choose a generic drug than the general-income group and the interquartile estimates ranged 0.92-1.02. The multivariate feasible generalized least squares model indicated high-income group's higher likelihood to choose brand-name drugs than the general-income group without co-payment rate differentiation (p < 0.001). Such gap in the likelihood was attenuated by 0.4% (p = 0.027) with an US$1 increase in the difference in additional payment/month for brand-name drugs between income groups - no gap with US$10 additional payment/month. This attenuation was observed in drugs for chronic diseases only, not for acute diseases.
conclusionsIncome-based co-payment rates appeared to reduce disparity in access to brand-name drugs across income groups, in addition to reducing total medical expenditure among high-income group who shifted from brand-name drugs to generic ones due to larger drug price differences.
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