OBJECTIVE To examine the association between expansion of the Medicaid program under the Affordable Care Act and changes in healthcare spending among low income adults during the first four years of the policy implementation (2014-17). DESIGN Quasi-experimental difference-in-difference analysis to examine out-of-pocket spending and financial burden among low income adults after Medicaid expansions. SETTING United States. PARTICIPANTS A nationally representative sample of individuals aged 19-64 years, with family incomes below 138% of the federal poverty level, from the 2010-17 Medical Expenditure Panel Survey. MAIN OUTCOMES AND MEASURES Four annual healthcare spending outcomes: out-of-pocket spending; premium contributions; out-of-pocket plus premium spending; and catastrophic financial burden (defined as out-of-pocket plus premium spending exceeding 40% of post-subsistence income). P values were adjusted for multiple comparisons. RESULTS 37 819 adults were included in the study. Healthcare spending did not change in the first two years, but Medicaid expansions were associated with lower out-of-pocket spending (adjusted percentage change -28.0% (95% confidence interval -38.4% to -15.8%); adjusted absolute change -$122 (£93; €110); adjusted P<0.001), lower out-of-pocket plus premium spending (-29.0% (-40.5% to -15.3%); -$442; adjusted P<0.001), and lower probability of experiencing a catastrophic financial burden (adjusted percentage point change -4.7 (-7.9 to -1.4); adjusted P=0.01) in years three to four. No evidence was found to indicate that premium contributions changed after the Medicaid expansions. CONCLUSION Medicaid expansions under the Affordable Care Act were associated with lower out-of-pocket spending and a lower likelihood of catastrophic financial burden for low income adults in the third and fourth years of the act's implementation. These findings suggest that the act has been successful nationally in improving financial risk protection against medical bills among low income adults.

中文翻译：

---

美国医疗补助扩张后低收入成年人的自付费用和财务负担：准实验差异研究。

目的 研究在政策实施的前四年（2014-17 年），根据平价医疗法案扩大医疗补助计划与低收入成年人医疗保健支出变化之间的关联。设计 准实验差异分析，以检查医疗补助扩张后低收入成年人的自付费用和财务负担。设置美国。参与者 来自 2010-17 年医疗支出小组调查的具有全国代表性的 19-64 岁个人样本，家庭收入低于联邦贫困线的 138%。主要成果和措施 四项年度医疗支出成果： 自费支出；保费供款；自付费用加保费支出；和灾难性的财务负担（定义为自付费用加上超过维持生计收入 40% 的保费支出）。P值针对多重比较进行了调整。结果 37 819 名成人被纳入研究。前两年的医疗保健支出没有变化，但医疗补助扩张与较低的自付费用相关（调整后的百分比变化 -28.0%（95% 置信区间 -38.4% 至 -15.8%）；调整后的绝对变化 - 122 美元（93 英镑；110 欧元）；调整后的 P<0.001），较低的自付费用加保费支出（-29.0%（-40.5% 至 -15.3%）；-442 美元；调整后的 P<0.001），以及较低的在第三至第四年经历灾难性的财务负担（调整后的百分点变化 -4.7（-7.9 至 -1.4）；调整后的 P=0.01）。没有发现任何证据表明医疗补助扩张后保费缴款发生了变化。结论 平价医疗法案下的医疗补助扩张与较低的自付费用和较低的低收入成年人在该法案实施的第三年和第四年发生灾难性经济负担的可能性有关。这些调查结果表明，该法案在全国范围内成功地改善了低收入成年人对医疗费用的财务风险保护。