Health Reform and Coverage Changes Among Native Americans

The Affordable Care Act (ACA) expands health insurance for Native Americans through Medicaid and Marketplace coverage, despite Native Americans being exempt from the law’s individual mandate. The ACA also permanently reauthorized the Indian Health Care Improvement Act, which funds the Indian Health Service (IHS). The IHS provides health care services to 2.2 million Native Americans annually but is not considered insurance by the US government.¹ We evaluated changes in insurance and IHS coverage among Native Americans following the ACA’s implementation.

We used the 2012-2014 American Community Survey (ACS), administered by the US Census Bureau. The survey is mailed to 3.5 million households annually, with a response rate of 90% to 97%.² The ACS can be used to evaluate changes in health insurance in states and smaller geographic areas.³

Our sample included individuals aged 0 to 64 years reporting “American Indian or Alaska Native” race (US Census terminology for Native Americans). Analyses were conducted at 2 geographic levels: nationally, and among Native American reservations containing populated land in both a Medicaid expansion and nonexpansion state. Reservations were approximated using ACS public use microdata areas.²

First, we assessed overall national coverage changes. Then we used a differences-in-differences approach to compare pre-ACA (2012-2013) and post-ACA (2014) changes in outcomes between Medicaid expansion and nonexpansion states. The outcome was primary health insurance, in 4 mutually exclusive categories: Medicaid with IHS, Medicaid without IHS, private coverage, and uninsured. We also assessed overall rates of IHS coverage.

Models adjusted for demographics and employment. We used national survey weights and robust standard errors clustered by state. Two-sided P < .05 was considered significant. The study used publicly available data, and institutional review board approval was waived by Harvard University.

Our national and reservation samples included 168 654 and 24 575 nonelderly Native Americans, respectively (Table 1). The reservation sample was poorer, younger, and less likely to be employed.

Nationally, the Native American uninsured rate dropped from 24.8% to 20.6% (P < .001). The national differences-in-differences estimate for Medicaid expansion was a 2.9 percentage-point decline in the uninsured rate (95% CI, −4.4 to −1.5; P < .001), and a decline of 8.6 percentage points (95% CI, −15.6 to −1.7; P = .02) in the reservation sample (Table 2). Medicaid coverage (with or without IHS) increased nationally, with coverage gains roughly equally divided between those with and without concurrent IHS. On reservations, however, most Medicaid coverage gains occurred among those also reporting IHS. Reductions in private coverage were nonsignificant, with estimates ranging from −1.5 (95% CI, −3.3 to 0.4; P = .12) to −2.0 (95% CI, −12.4 to 8.4; P = .68) percentage points. Overall changes in IHS were also nonsignificant.

We tested whether coverage was differentially changing in expansion vs nonexpansion states in 2013 (pre-ACA). Nationally, we detected 2 significant changes for expansion vs nonexpansion states: 0.8 percentage points in Medicaid with IHS (95% CI, 0.1 to 1.6; P = .03) and −1.8 percentage points in private coverage (95% CI, −3.3 to −0.2; P = .02). Uninsured and IHS rates were stable (−0.1; 95% CI, −1.9 to 1.7; P = .91; and 0.4; 95% CI, −2.0 to 2.8; P = .74, respectively), and there were no significant differential changes in the reservation sample. Repeating the Table 2 regressions for the national sample adjusting for differential linear time trends for expansion vs nonexpansion states produced results similar to our main findings, except that the 2014 change in Medicaid with IHS became nonsignificant (−0.1; 95% CI, −1.2 to 1.0; P = .82).

The ACA was associated with significant coverage increases for Native Americans, primarily in Medicaid expansion states, consistent with national trends for all racial/ethnic groups.^4,5 Nationally, much of the coverage increase occurred among Native Americans without connections to IHS. Among those living on or near reservations, Medicaid gains were concentrated among those also reporting IHS coverage, whose health care costs at IHS facilities can now be reimbursed by Medicaid. Meanwhile, there was no net change in IHS rates, suggesting that Medicaid expansion is supplementing rather than replacing IHS. Moreover, this finding suggests that the law may bring additional resources from Medicaid into IHS, which has struggled with budget shortfalls.⁶

Study limitations include only 1 year of post-ACA data, imprecise measurement of income and insurance in survey data, and the absence of health care utilization data in the ACS. Finally, factors besides the ACA may have differentially affected coverage in expansion and nonexpansion states.

Corresponding Author: Benjamin D. Sommers, MD, PhD, Department of Health Policy and Management, Harvard T. H. Chan School of Public Health, 677 Huntington Ave, Room 406, Boston, MA 02115 (bsommers@hsph.harvard.edu).

Published Online: May 16, 2016. doi:10.1001/jamainternmed.2016.1695.

Author Contributions: Ms Frean had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: All authors.

Acquisition, analysis, or interpretation of data: Frean, Sequist, Sommers.

Drafting of the manuscript: Frean, Shelder, Sommers.

Critical revision of the manuscript for important intellectual content: Frean, Rosenthal, Sequist, Sommers.

Statistical analysis: Frean, Sommers.

Obtained funding: Sommers.

Administrative, technical, or material support: Sequist.

Study supervision: Sequist, Sommers.

Conflict of Interest Disclosures: Dr Sommers serves in the Office of the Assistant Secretary for Planning and Evaluation at the US Department of Health and Human Services (DHHS). No other disclosures are reported.

Funding/Support: Dr Sommers and Ms Frean were supported by grant No. K02HS021291 from the Agency for Healthcare Research and Quality (AHRQ).

Role of the Funder/Sponsor: The AHRQ had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Disclaimer: The views presented herein are those of the authors and do not represent the DHHS or AHRQ.