Asiimwe Edgar, May Folasade, Bendavid Eran
Division of General Internal Medicine, UCSF, San Francisco, California, USA
National Clinician Scholars Program at UCSF, San Francisco, California, USA.
BMJ Open. 2025 Jun 23;15(6):e099058. doi: 10.1136/bmjopen-2025-099058.
Studies examining the association between Medicaid expansion (ME) under the Affordable Care Act (ACA) and colon cancer incidence have produced mixed results.
To re-visit the association between the ACA-ME and annual cases of colon cancer.
Difference-in-differences (DiD).
The primary analyses used data from the National Cancer Database from 2010 to 2018, a hospital-based cancer registry in the USA. We also conducted exploratory analyses using data from the Surveillance, Epidemiology and End Results (SEER) registry.
Patients aged 40 and older with newly diagnosed colon cancer.
The primary outcome was the percent change in colon cancer of all stages. Secondary outcomes were percent changes in stage I and stage IV cases.
Among those aged 40-49, we observed a statistically significant greater increase in stage I colon cancer in expansion states relative to non-expansion states (DiD (percent change) 9.7% (95% CI, 2.5% to 17.4%)). In those aged 50-64, we did not observe statistically significant differences between the two state groups in any of the outcomes. Among those aged 65+, we observed a statistically significant relative decrease for all stages in ACA-ME states (-1.0% (95% CI, -1.0% to -3.0%)) and for stage IV (-3.0% (95% CI, -2.0% to -5.0%)). We explored our findings among younger individuals (<50) in trend plots comparing annual colorectal cancer cases to percent uninsured using SEER data and observed that increases in cases coincided with declining uninsurance in several states.
Post-ME, we observed a greater relative increase in colon cancer among those <50 in expansion states. Our exploratory analyses suggest that fewer barriers to healthcare post-ME may have contributed to these findings; additional studies are needed. We also observed relative decreases in the 65+ age group, corroborating previous reports of spillover benefits in expansion states.
关于《平价医疗法案》（ACA）下的医疗补助扩大计划（ME）与结肠癌发病率之间关联的研究结果不一。
重新探讨ACA-ME与结肠癌年度病例之间的关联。
差异-in-差异（DiD）分析。
主要分析使用了2010年至2018年美国国家癌症数据库的数据，该数据库是一个基于医院的癌症登记处。我们还使用监测、流行病学和最终结果（SEER）登记处的数据进行了探索性分析。
年龄在40岁及以上且新诊断为结肠癌的患者。
主要结局是各阶段结肠癌的百分比变化。次要结局是I期和IV期病例的百分比变化。
在40-49岁人群中，我们观察到与非扩大州相比，扩大州I期结肠癌的相对增加在统计学上具有显著意义（DiD（百分比变化）9.7%（95%CI，2.5%至17.4%））。在50-64岁人群中，我们未观察到两个州组在任何结局方面存在统计学上的显著差异。在65岁及以上人群中，我们观察到ACA-ME州所有阶段的相对减少具有统计学意义（-1.0%（95%CI，-1.0%至-3.0%）），IV期为（-3.0%（95%CI，-2.0%至-5.0%））。我们使用SEER数据在趋势图中比较了年轻个体（<50岁）的年度结直肠癌病例与未参保百分比，以探索我们的发现，并观察到在几个州病例增加与未参保率下降同时出现。
在ME实施后，我们观察到扩大州中<50岁人群的结肠癌相对增加幅度更大。我们的探索性分析表明，ME实施后医疗保健障碍减少可能促成了这些发现；需要进一步研究。我们还观察到65岁及以上年龄组的相对减少，这证实了先前关于扩大州溢出效益的报告。
