Department of Obstetrics and Gynecology, University of Pennsylvania Health System, Philadelphia, PA; Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC.
Department of Obstetrics and Gynecology, University of Pennsylvania Health System, Philadelphia, PA.
Am J Obstet Gynecol. 2021 Feb;224(2):195.e1-195.e17. doi: 10.1016/j.ajog.2020.08.007. Epub 2020 Aug 7.
Women with gynecologic cancer face socioeconomic disparities in care that affect survival outcomes. The Affordable Care Act offered states the option to expand Medicaid enrollment eligibility criteria as a means of improving timely and affordable access to care for the most vulnerable. The variable uptake of expansion by states created a natural experiment, allowing for quasi-experimental methods that offer more unbiased estimates of treatment effects from retrospective data than the traditional regression adjustment.
To use a quasi-experimental, difference-in-difference framework to create unbiased estimates of impact of Medicaid expansion on women with gynecologic cancer.
We performed a quasi-experimental retrospective cohort study from the National Cancer Database files for women with invasive cancers of the uterus, ovary and fallopian tube, cervix, vagina, and vulva diagnosed from 2008 to 2016. Using a marker for state Medicaid expansion status, we created difference-in-difference models to assess the impact of Medicaid expansion on the outcomes of access to and timeliness of care. We excluded women aged <40 years owing to the suppression of the state Medicaid expansions status in the data and women aged ≥65 years owing to the universal Medicare coverage availability. Our primary outcome was the rate of uninsurance at diagnosis. Secondary outcomes included Medicaid coverage, early-stage diagnosis, treatment at an academic facility, and any treatment or surgery within 30 days of diagnosis. Models were run within multiple subgroups and on a propensity-matched cohort to assess the robustness of the treatment estimates. The assumption of parallel trends was assessed with event study time plots.
Our sample included 335,063 women. Among this cohort, 121,449 were from nonexpansion states and 213,614 were from expansion states, with 79,886 posttreatment cases diagnosed after the expansion took full effect in expansion states. The groups had minor differences in demographics, and we found occasional preperiod event study coefficients diverging from the mean, but the outcome trends were generally similar between the expansion and nonexpansion states in the preperiod, satisfying the necessary assumption for the difference-in-difference analysis. In a basic difference-in-difference model, the Medicaid expansion in January 2014 was associated with significant increases in insurance at diagnosis, treatment at an academic facility, and treatment within 30 days of diagnosis (P<.001 for all). In an adjusted model including all states and accounting for variable expansion implementation time, there was a significant treatment effect of Medicaid expansion on the reduction in uninsurance at diagnosis (-2.00%; 95% confidence interval, -2.3 to -1.7; P<.001), increases in early-stage diagnosis (0.80%; 95% confidence interval, 0.2-1.4; P=.02), treatment at an academic facility (0.83%; 95% confidence interval, 0.1-1.5; P=.02), treatment within 30 days (1.62%; 95% confidence interval, 1.0-2.3; P<.001), and surgery within 30 days (1.54%; 95% confidence interval, 0.8-2.3; P<.001). In particular, large gains were estimated for women living in low-income zip codes, Hispanic women, and women with cervical cancer. Estimates from the subgroup and propensity-matched cohorts were generally consistent for all outcomes besides early-stage diagnosis and treatment within 30 days.
Medicaid expansion was significantly associated with gains in the access and timeliness of treatment for nonelderly women with gynecologic cancer. The implementation of Medicaid expansion could greatly benefit women in nonexpansion states. Gynecologists and gynecologic oncologists should advocate for Medicaid expansion as a means of improving outcomes and reducing socioeconomic and racial disparities.
患有妇科癌症的女性在护理方面存在社会经济差异，这会影响生存结果。《平价医疗法案》为各州提供了扩大医疗补助计划参保资格标准的选择，以此作为改善最弱势群体及时和负担得起的护理机会的手段。各州对扩张的不同接受程度创造了一个自然实验，允许使用准实验方法从回顾性数据中获得比传统回归调整更无偏的治疗效果估计。
使用准实验、差异中的差异框架来创建关于医疗补助计划扩张对妇科癌症女性影响的无偏估计。
我们从 2008 年至 2016 年期间诊断为子宫、卵巢和输卵管、宫颈、阴道和外阴浸润性癌症的女性的国家癌症数据库文件中进行了准实验回顾性队列研究。使用州医疗补助计划扩张状态的标志物，我们创建了差异中的差异模型，以评估医疗补助计划扩张对获得和及时护理的结果的影响。我们排除了年龄<40 岁的女性，因为数据中抑制了州医疗补助计划扩张状态，以及年龄≥65 岁的女性，因为普遍提供了医疗保险覆盖。我们的主要结局是诊断时无保险的比率。次要结局包括医疗补助覆盖、早期诊断、在学术机构治疗以及在诊断后 30 天内进行任何治疗或手术。在多个亚组和倾向匹配队列中运行模型，以评估治疗估计的稳健性。使用事件研究时间图评估平行趋势的假设。
我们的样本包括 335063 名女性。在这一组中，121449 名来自非扩张州，213614 名来自扩张州，在扩张州的扩张全面生效后，有 79886 例治疗后病例被诊断。两组在人口统计学方面存在微小差异，并且我们偶尔会发现前周期事件研究系数与平均值背离，但在扩张和非扩张状态的前周期中，结果趋势总体上相似，满足了差异中的差异分析的必要假设。在基本的差异中的差异模型中，2014 年 1 月的医疗补助计划扩张与诊断时保险增加、在学术机构治疗和诊断后 30 天内治疗显著相关（所有 P<.001）。在包括所有州并考虑到不同扩张实施时间的调整模型中，医疗补助计划扩张对减少诊断时无保险（-2.00%；95%置信区间，-2.3 至-1.7；P<.001）、早期诊断增加（0.80%；95%置信区间，0.2-1.4；P=.02）、在学术机构治疗（0.83%；95%置信区间，0.1-1.5；P=.02）、在诊断后 30 天内治疗（1.62%；95%置信区间，1.0-2.3；P<.001）和在诊断后 30 天内手术（1.54%；95%置信区间，0.8-2.3；P<.001）有显著的治疗效果。特别是，在低收入邮政编码、西班牙裔女性和宫颈癌女性中，估计值较大。除了早期诊断和 30 天内治疗外，所有结果的亚组和倾向匹配队列的估计值通常都一致。
医疗补助计划扩张与非老年妇科癌症女性获得和及时治疗的收益显著相关。医疗补助计划的实施可以使非扩张州的女性受益匪浅。妇科医生和妇科肿瘤医生应该倡导医疗补助计划扩张，以此作为改善结果和减少社会经济和种族差异的手段。
