The effect of health insurance expansion on price and demand for medications among the uninsured
中文摘要
社会医疗保险的扩张不仅会影响新受益人,也会影响仍未纳入该计划的人群。本文以医疗保险D部分(Medicare Part D)为背景研究这类溢出效应。参保需求的增加既可能抬高也可能降低价格,取决于市场状况:当制药企业面临弹性较小的需求时,价格可能上升;而当需求集中度强化了竞争性市场中的议价与价格传导时,价格则可能下降。我发现Part D降低了65岁以下、无处方药保险的美国人所支付的自付单价。价格下降在受Part D影响更大的治疗类别以及类内竞争更强的类别中幅度更大,这与需求集中度渠道相一致。需求的增加主要来自仿制药和既有使用者。隐含的消费者剩余收益约为每人每年76美元,其中约65美元来自边际内消费的价格下降,约11美元来自额外消费。需求反应在收入较低、较年轻且较健康的未参保人群中似乎最强,这与该群体中原先存在的更高程度用药不依从相一致。尽管多个药物类别的价格有所下降,但在美国与过度使用关联更大的药物上,需求并未显著增加,这表明可能存在正的健康净溢出效应。
Abstract
Social health insurance expansions can affect not only new beneficiaries but also those who remain outside the program. This paper studies these spillovers in the context of Medicare Part D. Increases in insured demand can raise or lower price depending on market conditions: they may increase price when pharmaceutical firms face less elastic demand, but reduce price when demand concentration strengthens bargaining and pass-through in competitive markets. I find that Part D lowered the out-of-pocket unit price paid by Americans under age 65 without prescription drug insurance. Price declines are larger in therapeutic classes more exposed to Part D and in classes with stronger within-class competition, consistent with a demand-concentration channel. Demand increases mainly for generic drugs and among existing users. The implied consumer-surplus gain is roughly $76 per person per year, comprising about $65 from lower price on inframarginal consumption and $11 from additional consumption. Demand responses appear strongest among lower-income, younger, and healthier uninsured individuals, consistent with greater pre-existing non-adherence. Although price fall across several drug classes, demand does not increase significantly for medications associated with greater overuse in the United States, suggesting potentially positive net health spillovers.