Blythe J.S. Adamson, PhD, MPH Senior Quantitative Scientist Flatiron Health

Medicaid Expansion Reduced Racial Disparities in Cancer Treatment Interview with:

Blythe J.S. Adamson, PhD, MPH Senior Quantitative Scientist Flatiron Health

Dr. Adamson

Blythe J.S. Adamson, PhD, MPH
Senior Quantitative Scientist
Flatiron Health What is the background for this study?

Response: Racial disparities in access and outcomes have been documented across the full trajectory of cancer-related care. This includes access to prevention and screening, to early diagnosis, treatment, survival and other health outcomes. While these disparities have been well documented, finding mechanisms to reduce disparities is more challenging. One potential mechanism to reduce treatment disparities is to improve access to insurance coverage. The Affordable Care Act (ACA), passed in March 2010, included as its overall goals the improvement in healthcare quality and access, and enhancing equity in treatment and outcomes. The ACA allowed states to expand Medicaid to poor and near-poor adults, and this was implemented by many states starting in 2014. In addition, the ACA established private insurance marketplaces with income-based premium subsidies and limits on out-of-pocket spending for qualifying low-income enrollees.

Prior research has demonstrated that ACA Medicaid expansions are associated with increased coverage and improved overall access for cancer survivors; and for newly diagnosed patients, the ACA was associated with increased coverage and shifts to earlier stage diagnosis for some cancers. To our knowledge, no research has yet demonstrated that the ACA coverage expansions affected the process of cancer care, specific cancer treatments received or specific treatment outcomes, let alone whether disparities were reduced.  In this study we looked at the time from advanced/metastatic diagnosis to start of systemic treatment for black vs. white patients and based on whether they were diagnosed at a time and in a state that had vs. had not implemented Medicaid expansion. Our study hypothesis was that Medicaid expansion reduced disparity in timely treatment of black patients compared to white patients with advanced cancer. We defined timely treatment as start of systemic therapy within 30 days of advanced/metastatic diagnosis.

This is a retrospective observational study, not a randomized controlled trial. In other words, we selected a cohort of patients diagnosed with advanced or metastatic cancers over time and observed whether they received timely treatment. The Flatiron Health EHR-derived database was the principal data source for this research. Flatiron contributing practices include 280 cancer community based clinics and academic hospital outpatient settings (~800 sites of care) representing more than 2.2 million patients with cancer in the United States. Practices are located in 40 states. To produce the database, Flatiron extracted data from structured fields, including demographics, and recorded medication orders and administrations. Flatiron also abstracted unstructured data, using technology assisted review by highly trained clinicians. Abstracted data include diagnosis date, stage, and prescribed oral anticancer medications. The database used for research purposes was de-identified. We also used data from the Kaiser Family Foundation which has tracked Medicaid implementation policies for over twenty years, and the US Bureau of Labor Statistics from which we pulled state-year unemployment rates. What are the main findings?

Response: Our total sample included over 30,000 patients diagnosed with advanced cancer. The largest groups were non-small cell lung cancer, colorectal cancer, and breast cancer. We see that overall, for patients diagnosed under a non-expanded regime, an adjusted 47.7% received timely treatment, 48.3% for white patients and 43.5% for black patients. With Medicaid expansion, timely treatment increased to an adjusted 50.3% for white patients and 49.6% for black patients.Without expansion, the adjusted difference or disparity in timely treatment by race was 4.8 percentage points. With Medicaid expansion the disparity decreased to 0.8 percentage points and was no longer significant. The difference in difference estimate is 4.0. percentage points. In other words, the incremental effect of Medicaid expansion on black patients was 4 percentage points greater than the effect for white patients. What should readers take away from your report?

Response: Our study results indicate that Medicaid expansion was associated with reduced racial disparities in timely cancer treatment. This research, which focused on disparities in the process of cancer care, extends prior evidence of the effects of ACA expansions on coverage and access. This study provides important evidence of how national healthcare coverage policy can be used as a mechanism to reduce disparities in cancer care. This study also illustrates how enhanced EHR data, with large samples and wide geographic coverage, can be a valuable resource to assess cancer treatments, disparities, and potential interventions to address them. What recommendations do you have for future research as a result of this work? 

Response: We hope this research encourages others to apply real world data for real-time evaluation of healthcare policies. We want to encourage other researchers to leverage other datasets to replicate this analysis and examine other cancer outcomes. Data science tools are making it easier to conduct these computationally burdensome studies. Is there anything else you would like to add?

Response: As with all studies, there are limitations. Our outcome is receipt of systemic therapy within 30 days after diagnosis with an advanced cancer. We selected it as a metric associated with a better patient experience, but it isn’t a perfect surrogate for overall survival. Also, there is the potential for misclassification in our measure of timely treatment, which includes systemic therapy but not other modalities. While we do not expect that this misclassification will result in bias by race or expansion status, we are exploring strategies to refine this measure.


ASCO 2019 abstract, Affordable Care Act (ACA) Medicaid expansion impact on racial disparities in time to cancer treatment, presented Sunday, June 2, 2019.


Blythe J.S. Adamson, Aaron B. Cohen, Melissa Estevez, Kelly Magee, Erin Williams, Cary Philip Gross, Neal J. Meropol, Amy J. Davidoff; Flatiron Health, New York, NY; Yale School of Medicine, New Haven, CT; Yale School of Public Health, New Haven, CT

[wysija_form id=”3″]

Jun 6, 2019 @ 10:34 pm

The information on is provided for educational purposes only, and is in no way intended to diagnose, cure, or treat any medical or other condition. Always seek the advice of your physician or other qualified health and ask your doctor any questions you may have regarding a medical condition. In addition to all other limitations and disclaimers in this agreement, service provider and its third party providers disclaim any liability or loss in connection with the content provided on this website.