In addition to the Medicaid expansion, The Patient Protection and Affordable Care Act (ACA, P.L. 111-148, as amended) established premium subsidies for the purchase of private coverage on the exchanges for those with incomes between 100 percent and 400 percent of the federal poverty level (FPL). Together with other changes to the insurance market, these new coverage options were intended to increase the number of individuals with health insurance coverage (CBO 2010). It also was anticipated that gains in health coverage would lead to improved access to and use of services.
Enrollment data provide only one data point; to understand the broader impact on coverage, survey data need to be examined. This is the case because the expected increase in the number of covered individuals also reflect the cumulative effect of the Medicaid expansion, other increases in Medicaid enrollment, exchange enrollment, and any new enrollment in employer-sponsored coverage. For more information, see Medicaid enrollment changes following the ACA.
Federal surveys, with their large sample sizes, provide a more complete assessment of the ACA’s impact on coverage rates, although a number of smaller, private surveys have provided early estimates on the law’s effect. Survey data released to date have shown a decline in the number of uninsured adults and a corresponding increase in Medicaid coverage. States that have expanded Medicaid have lower rates of uninsurance than non-expansion states. For example, according to the Current Population Survey, the uninsured rate was lower in states that expanded Medicaid (6.5 percent) than in those states that did not (11.7 percent) (Barnett and Berchick 2017).
Several studies have found that there has been a decline in the uninsured rate following the Medicaid expansion, with greater declines in Medicaid expansion states. An article in Health Affairs found that the uninsured rate fell in both expansion and non-expansion states between 2010 and 2015, but that declines were significantly greater (7.5 percentage points) in expansion states. This study also found that Medicaid expansion was associated with significantly better quality of coverage as reported by low-income adults (Decker et al. 2017). Another Health Affairs article found that 18 percent of individuals who were uninsured in 2013, gained coverage through Medicaid. Only 11 percent of individuals who were uninsured in 2013 remained uninsured in 2014 (Kirby and Vistnes 2016).
Additionally, a recent study found a link between parents gaining Medicaid eligibility and increased enrollment among children. Among children whose parents gained coverage under the Medicaid expansion, public coverage increased by 5.7 percentage points versus 2.7 percentage points among children whose parents remained ineligible for Medicaid following the expansion (including those who remained ineligible due to their state not expanding Medicaid or for a different reason). The study also estimated that an additional 200,000 low-income children would have gained coverage if all states had adopted the expansion (Hudson and Moriya 2017).
Estimates suggest that more than one-fourth (6.8 million) of the remaining uninsured population is eligible for Medicaid or CHIP. An additional 2.4 million uninsured individuals fall into the so-called coverage gap, meaning that they earn too much to be eligible for Medicaid, but not enough to qualify for subsidized exchange coverage. These individuals would likely be eligible for Medicaid if their states had chosen to expand coverage (Garfield et al. 2017).
Access to care and service use
Several studies suggest that newly insured adults are using care. The data do not, however, consistently distinguish between those with Medicaid and other sources of coverage or all Medicaid enrollees and the new adult group, although some provide data by income. For example:
- Several studies examined the impact of gaining coverage (either through Medicaid or in general) on unmet need, and on having a usual source of care among low-income adults:
- A May 2017 study from the Commonwealth Fund using data from the National Health Interview Survey and the Behavioral Risk Factor Surveillance System found that following the first open enrollment period of October 2013 to March 2014, previously uninsured individuals gaining coverage through Medicaid expansions were between 47.1 and 85.6 percent more likely to report having a usual source of care (Glied, Ma, and Borja 2017).
- A study from the Urban Institute Health Policy Center used data from the September 2015 round of the Health Reform Monitoring Survey and found that individuals with Medicaid coverage were just as likely to report having a usual source of care or a recent routine checkup, but more likely to report difficulty getting a doctor’s appointment than other insured enrollees. Compared with enrollees in exchange plans, Medicaid enrollees were less likely to report unmet health needs due to affordability or problems paying medical bills (Holahan et al. 2016).
- An article in Health Affairs found that, nationally, adults with income below 138 percent FPL were more likely to report a usual source of care as well as a routine checkup within the last year than prior to implementation of the ACA. This study also reported a decline in unmet need due to cost and problems paying family medical bills. However, more than 20 percent also reported an access problem within the past 12 months (Shartzer et al. 2016).
- A study from the Kaiser Family Foundation found that adults who gained coverage were more likely to have a usual source of care, regardless of coverage type. They also were more likely to have used medical care compared to those who remained uninsured. However, newly insured adults were more likely to reports difficulties finding a physician that would take them as a new patient (Garfield and Young 2015).
- One study found that adults with incomes between 100 and 138 percent FPL experienced similar increases in having a usual source of care and primary care whether covered by Medicaid in expansion states or by the exchanges in non-expansion states. However, adults in expansion states experienced larger reductions in out-of-pocket spending but greater difficulty accessing physicians relative to their counterparts in non-expansion states (Selden et al. 2017).
- Several studies examined the impact of Medicaid expansion on Medicaid-covered utilization of specific types of services:
- A study published in 2018 found that Medicaid expansion was associated with improved receipt of timely care among hospital patients with five common surgical conditions: appendicitis, cholecystitis, diverticulitis, peripheral artery disease, and aortic aneurysm. Specifically, it was associated with a 1.8 percentage point increase in the probability of early uncomplicated presentation and a 2.7 percentage point increase in the probability of receiving optimal management (Loehrer et al 2018).
- A study in Annals of Emergency Medicine found that following Medicaid expansion in 2014, total emergency department use per 1,000 population increased by an additional 2.5 visits in expansion states compared to non-expansion states. The share of emergency department visits covered by Medicaid increased by 9 percentage points and the share of emergency department visits that were uninsured decreased by 5 percentage points relative to non-expansion states (Nikpay, et al 2017).
- A study in the Annals of Internal Medicine found that in the second half of 2014, Medicaid expansions were associated with higher utilization of certain services (including those provided by general practitioners and overnight hospital stays), and increased diagnoses for certain health conditions (diabetes and high cholesterol) in adults with incomes below 138 percent FPL as compared to their counterparts in non-expansion states (Wherry and Miller 2016).
- A National Bureau of Economic Research study found that in the first 15 months of Medicaid expansion, Medicaid-covered prescription drug utilization increased by 19 percent in expansion states relative to non-expansion states. The largest increases in Medicaid-covered prescriptions were for diabetes medications, contraceptives, and cardiovascular drugs. Increases were greatest in geographic areas with high pre-ACA uninsured rates and with large Hispanic and black populations. There were no significant reductions in prescriptions among uninsured, Medicare, or privately insured populations. The authors note that this indicated that increases in Medicaid utilization did not substitute for previous sources of coverage (Ghosh et al. 2017).
- A 2017 study in the American Journal of Public Health found that Medicaid expansion was associated with a 3.4 percent increase in overall cancer diagnosis rates and a 6.4 percent increase in early-stage diagnoses among the working-age population (Soni et al. 2017).
- Additionally, several studies have examined the impact of Medicaid expansion on use of Medicaid-covered behavioral health and substance use disorder (SUD) treatment:
- A 2017 Government Accountability Office (GAO) report found that in four expansion states—Iowa, New York, Washington, and West Virginia—between 20 and 34 percent of expansion enrollees received behavioral health treatment in 2014, including psychotherapy and prescription drugs. Among individuals in these states diagnosed with opioid abuse or dependence, between 62 and 81 percent used some outpatient treatment services, and between 11 and 41 percent used medication-assisted treatment (GAO 2017).
- An April 2017 article in Medical Care found that state adoption of Medicaid expansion was associated with a 70 percent increase in Medicaid-covered buprenorphine prescriptions and a 50 percent increase in Medicaid spending on these prescriptions, suggesting improved access to treatment. Increases in non-expansion states were not significant (Wen et al. 2017).
- An April 2017 National Bureau of Economic Research article found that postexpansion, there was no evidence of increased admission to specialty treatment for SUD in expansion states relative to non-expansion states. However, Medicaid-covered prescriptions for outpatient medications used for SUD treatment increased by 33 percent in expansion states relative to non-expansion states (Maclean and Saloner 2017).
- A June 2016 article in Health Affairs found that in 2014, the uninsurance rate among adults who reported past-year criminal justice contact and met screening criteria for SUD declined from 38 to 28 percent. However, overall treatment rates among this population were unchanged in 2014 (Saloner et al. 2016).
Effect of alternative approaches to expansion
A series of articles looked at three states, Arkansas, Kentucky, and Texas, in order to compare individuals in states taking different approaches to expansion to a non-expansion state.
- A May 2017 study in Health Affairs found that by the end of 2016, the uninsured rate in Kentucky and Arkansas declined by more than 20 percentage points relative to the uninsured rate in Texas. Among previously uninsured individuals, gaining coverage was associated with a 41 percentage point increase in the likelihood of having a usual source of care as well as a 23 percentage point increase in the likelihood of being in self-reported excellent health. Additionally, it was associated with a $337 decrease in average annual out-of-pocket spending (Sommers et al. 2017).
- An October 2016 study in Journal of the American Medical Association found that, in 2015, the second year of expansion, Kentucky and Arkansas both saw significant changes in coverage and access. Expansion was associated with a 22.7 percent decrease in the uninsured rate; significant increases in access to primary care, outpatient utilization, preventive care, improved health quality, and improved self-reported health; and significant decreases in emergency department use. There were few differences found between Kentucky and Arkansas (Sommers et al. 2016).
- A January 2016 study in Health Affairs found that in the expansion states difficulty paying for medical care and skipping medication due to cost declined. Additionally, the share of adults with chronic conditions who obtained regular care increased. There were few differences found based on the type of expansion, traditional in Kentucky compared to a waiver in Arkansas (Sommers et al. 2016).
Effect of expansion on other measures of well-being
A series of studies have examined the impact of Medicaid expansion on factors such as personal finances, psychological stress, and problems paying medical bills:
- A 2018 study in Health Affairs examined the effects of Medicaid versus exchange coverage on out-of-pocket spending and probability of being uninsured. Among adults with income between 100 and 138 percent FPL, living in an expansion state relative to a non-expansion state was associated with:
- a $344 reduction in average out-of-pocket spending,
- a 4.1 percentage point decline in the likelihood of having out-of-pocket spending in excess of 10 percent of income,
- a 7.7 percentage point decline in the probability of having any out-of-pocket spending at all, and
- a 5 percent decline in the probability of being uninsured (Blavin et al. 2018).
- One study found that between 2010 and 2015, Medicaid expansion resulted in increased coverage and decreased psychological stress and problems paying medical bills. It did not find any significant effects on health status, affordability of prescription drugs, or mental health care, and only limited effects on increased use of care overall (McMorrow et al. 2017).
- A study investigating the effect of Medicaid expansion on household financial health found that expansion reduced unpaid medical bills sent to collection by $3.4 billion in the first two years. It also found that individuals’ improved financial health led to better terms for available credit valued at $520 million per year (Brevoort et al. 2017).
- Another study examining the effect of the Medicaid expansion on individuals’ personal finances found that individuals in Medicaid expansion states experienced improved credit scores; reduced past due balances; and reduced probability of a medical collection of over $1,000, one or medical bills go to collection, derogatory balances of any time, and bankruptcy filings (Caswell and Waidmann 2017).
- An article in Health Affairs examined the impact of early Medicaid expansion in California on reduced payday borrowing. It found significant reductions in the number of loans and number of unique borrowers per month and in the amount of payday loan debt in early expansion counties in California relative to non-expansion counties nationwide (Allen et al. 2017).
Spillover effects on other public programs
Several articles have examined the spillover effects of increased insurance coverage on other public programs, recipients of other types of health insurance, as well as on crime, and have suggested positive or neutral impacts. For example:
- A September 2017 article examining the relationship between access to health care and criminal behavior found that following Medicaid expansion, reported instances of violent and property crime per 100,000 people fell by 5 percent in expansion states and 3 percent in non-expansion states, a statistically significant difference. Crime reductions were even more pronounced in counties that experienced the largest decreases in uninsured rates following expansion (Vogler 2017).
- An August 2017 article in Health Affairs found that in states that expanded Medicaid, allowing non-elderly adults to qualify without having to obtain a disability determination through the Supplemental Security Income (SSI) program, SSI participation decreased by 3 percent relative to non-expansion states after 2014 (Soni et al. 2017).
- An August 2017 article in the American Economic Journal examined the effect of Medicaid expansion on spending and utilization among Medicare beneficiaries. It found that a 1 percentage point increase in the share of non-elderly adults eligible for Medicaid was associated with a $477 reduction in average beneficiary spending for individuals dually eligible for Medicare and Medicaid (McInerney, Mellor, and Sabik 2017).
- A May 2017 article in Health Affairs examined whether increases in insurance coverage at the local level affected access to care for adults in the area that continuously had health insurance over the period. It found no relationship across eight measures of access (e.g., receipt of preventive care) and no relationship in vulnerable subpopulations, including Medicaid beneficiaries and individuals residing in health care professional shortage areas (Abdus and Hill, 2017).