Evaluating the benefits of health insurance on cancer care

Millions of Americans acquire their health insurance under the Affordable Care Act, including individuals from disadvantaged communities (as defined by a summary measure comprised of U.S. Census measures of income, education, and employment). Patients with one of the four leading causes of cancer deaths have lower rates of cancer-specific survival based on where they live, specifically based on their social determinants of health. The extent to which health insurance can ease the effects of these social determinants of health on cancer care is the subject of current research led by Dartmouth-Hitchcock Norris Cotton Cancer Center's Sandra Wong, MD, Vice President and Chair of the Department of Surgery. Her work, "The impact of health insurance status on cancer care in disadvantaged communities" was recently published in the journal, Cancer.

Wong's study finds that the effect of having health insurance appears to be more pronounced in those from disadvantaged communities, compared to more advantaged communities, through better access to cancer care. However, the differences attributed to social determinants of health were not fully mitigated. Insured patients from less disadvantaged communities still had higher odds of receiving cancer-directed surgery and better cancer-specific survival than insured patients from disadvantaged communities. Interestingly, Medicaid insurance was associated with a much more modest survival benefit in those from disadvantaged communities.

"We were seeking to examine the differential impact of health insurance on cancer care across communities with varying social determinants of health" says Wong. "To the best of our knowledge, this is the first national study to explore the interplay between health insurance and social determinants of health and the resultant impact on cancer care and cancer outcomes."

The Dartmouth-Hitchcock study collected Surveillance, Epidemiology, and End Results registry data for 364,507 patients diagnosed with the four highest causes of cancer deaths: breast cancer, prostate cancer, lung cancer, and colorectal cancer, between 2007 and 2011. In the entire cohort, 304,224 patients (83.5%) were insured, 43,572 (12%) had Medicaid coverage, and 16,711 (4.6%) were uninsured. A social determinant score was determined based on five measures of wealth, education, and employment. In order to quantify the differences in the effects of health insurance on these varying social strata, patients were stratified into quintiles, the lowest quintile representing the most disadvantaged communities. Logistic regression and Cox proportional hazards models were used to estimate associations and cancer-specific survival within each quintile. The models were respectively adjusted for age, sex, race/ethnicity, marital status, cancer type, and stage.

Researchers found a consistent relation between a community's relative advantage and cancer-specific care, survival and outcomes. Although health insurance appeared to lessen this relation, it did not fully eliminate the differences caused by the measured social determinants of health. Notably, patients from disadvantaged communities had a larger relative benefit from health insurance, which demonstrated their need for improved access to care.

"These data will help inform ongoing healthcare payment reform efforts," says Wong. "Those from the most disadvantaged communities benefit the most from health insurance, but there are still disparities compared the most advantaged communities. Provisions for insurance are necessary but insufficient to eliminate inequities in cancer outcomes. Attention is also needed for community-level efforts and closer examination of the social determinants of health."