What happens when patients suddenly stop their medications? We study the health consequences of drug interruptions caused by large, abrupt, and arbitrary changes in price. Medicare’s prescription drug benefit as-if-randomly assigns 65-year-olds a drug budget as a function of their birth month, beyond which out-of-pocket costs suddenly increase. Those facing smaller budgets consume fewer drugs and die more: mortality increases 0.0164 percentage points per month (13.9%) for each ${\$}$100 per month budget decrease (24.4%). This estimate is robust to a range of falsification checks, and lies in the 97.8th percentile of 544 placebo estimates from similar populations that lack the same idiosyncratic budget policy. Several facts help make sense of this large effect. First, patients stop taking drugs that are both ‘high-value,’ and suspected to cause life-threatening withdrawal syndromes when stopped. Second, using machine learning, we identify patients at the highest risk of drug-preventable adverse events. Contrary to the predictions of standard economic models, high-risk patients (e.g., those most likely to have a heart attack) cut back more than low-risk patients on exactly those drugs that would benefit them the most (e.g., statins). Finally, patients appear unaware of these risks. In a survey of 65-year-olds, only one-third believe that stopping their drugs for up to a month could have any serious consequences. We conclude that, far from curbing waste, cost-sharing is itself highly inefficient, resulting in missed opportunities to buy health at very low cost (${\$}$11,321 per life-year).

中文翻译：

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成本分摊的健康成本


当患者突然停止服药时会发生什么？我们研究了价格的大幅、突然和任意变化导致药物中断对健康的影响。Medicare 的处方药福利根据 65 岁的出生月份随机分配药物预算，超过该预算后，自付费用会突然增加。那些预算较少的人消耗的药物更少，死亡更多：每月预算每减少 100 美元 （24.4%），死亡率每月增加 0.0164 个百分点 （13.9%）。该估计值对一系列证伪检查是稳健的，并且位于来自缺乏相同特殊预算政策的类似人群的 544 个安慰剂估计值的第 97.8 个百分位。有几个事实有助于理解这种巨大的影响。首先，患者停止服用既“高价值”又疑似在停药后会导致危及生命的戒断综合征的药物。其次，使用机器学习，我们识别药物可预防不良事件风险最高的患者。与标准经济模型的预测相反，高危患者（例如，最有可能心脏病发作的患者）比低风险患者减少对他们最有益的药物（例如他汀类药物）的剂量。最后，患者似乎没有意识到这些风险。在一项针对 65 岁人群的调查中，只有三分之一的人认为停药长达一个月可能会产生任何严重后果。我们得出的结论是，成本分摊非但不能遏制浪费，反而本身效率非常低下，导致错过了以极低成本（每生命年 11,321 美元）购买健康的机会。