Effects of ACA Medicaid Expansions on Health Insurance Coverage and Labor Supply

The effects of Medicaid expansion on the racial/ethnic composition within nursing home residents

BACKGROUND

The Affordable Care Act (ACA), enacted in 2010, aimed to improve healthcare coverage for American citizens. This study investigates the impact of Medicaid expansion (ME) under the ACA on the racial and ethnic composition of nursing home admissions in the U.S., focusing on whether ME has led to increased representation of racial/ethnic minorities in nursing homes.

METHODS

A difference-in-differences estimation methodology was employed, using U.S. county-level aggregate data from 2000 to 2019. This approach accounted for multiple time periods and variations in treatment timing to analyze changes in the racial and ethnic composition of nursing home admissions post-ME. Additionally, two-way fixed effects (TWFE) regression was utilized to enhance robustness and validate the findings.

RESULTS

The analysis revealed that the racial and ethnic composition of nursing home admissions has become more homogeneous following Medicaid expansion. Specifically, there was a decline in Black residents and an increase in White residents in nursing homes. Additionally, significant differences were found when categorizing states by income inequality, and poverty rate levels. These findings remain statistically significant even after controlling for additional variables, indicating that ME influences the racial makeup of nursing home admissions.

CONCLUSIONS

Medicaid expansion has not diversified nursing home demographics as hypothesized; instead, it has led to a more uniform racial composition, favoring White residents. This trend may be driven by nursing home preferences and financial incentives, which could favor residents with private insurance or higher personal funds. Mechanisms such as payment preferences and local cost variations likely contribute to these shifts, potentially disadvantaging Medicaid-reliant minority residents. These findings highlight the complex interplay between healthcare policy implementation and racial disparities in access to long-term care, suggesting a need for further research on the underlying mechanisms and implications for policy refinement.

Medicaid Expansion and Preventable Emergency Department Use by Race/Ethnicity

INTRODUCTION

This study aimed to examine changes in emergency department (ED) visits for ambulatory care sensitive conditions (ACSCs) among uninsured or Medicaid-covered Black, Hispanic, and White adults aged 26-64 in the first 5 years of the Affordable Care Act Medicaid expansion.

METHODS

Using 2010-2018 inpatient and ED discharge data from nine expansion and five nonexpansion states, an event study difference-in-differences regression model was used to estimate changes in number of annual ACSC ED visits per 100 adults ("ACSC ED rate") associated with the 2014 Medicaid expansion, overall and by race/ethnicity. A secondary outcome was the proportion of ACSC ED visits out of all ED visits ("ACSC ED share"). Analyses were conducted in 2022-2023.

RESULTS

Medicaid expansion was associated with no change in ACSC ED rates among all, Black, Hispanic, or White adults. When excluding California, where most counties expanded Medicaid before 2014, expansion was associated with a decrease in ACSC ED rate among all, Black, Hispanic, and White adults. Expansion was also associated with a decrease in ACSC ED share among all, Black, and White adults. White adults experienced the largest reductions in ACSC ED rate and share.

CONCLUSIONS

Medicaid expansion was associated with reductions in ACSC ED rates in some expansion states and reductions in ACSC ED share in all expansion states combined, with some heterogeneity by race/ethnicity. Expansion should be coupled with policy efforts to better link newly insured Black and Hispanic patients to non-ED outpatient care, alongside targeted outreach and expanded primary care capacity, which may reduce disparities in ACSC ED visits.

Effects of the Affordable Care Act Medicaid Expansions on the Employment and Work Hours of Nursing Assistants in Hospitals and Nursing Homes

We examine the effects of the Affordable Care Act Medicaid expansions on the employment and work hours of nursing assistants (NAs). We use the 2011-2019 American Community Survey data to identify NAs likely to be affected by Medicaid expansions (income up to 138% of the federal poverty level) in nursing homes and hospitals. Using classical difference-in-differences regressions, we find that Medicaid expansions have little effect on employment and work hours among NAs in the full sample. However, there is a 4.4 percentage-point increase in the probability of working part-time (<30 hours/week) for nursing home NAs (p < .05). We found no employment effects of Medicaid expansions for hospital NAs. Our study adds to the literature on the heterogeneous effects of Medicaid expansions on work effort across occupations and workplaces. The rise in part-time employment for nursing home NAs following Medicaid expansions suggests the need for improved benefits to encourage full-time employment.

Racial/Ethnic Differences in Association Between Medicaid Expansion and Causes and Costs of Readmission After Acute Ischemic Stroke

OBJECTIVE

The purpose of this study was to examine whether the relative frequency of leading causes and total associated costs of readmission after acute ischemic stroke changed with Medicaid expansion, and how these changes differed by racial/ethnic group.

METHODS

We used a difference-in-differences approach to compare changes in the relative frequency of leading causes of unplanned 30-day readmission and to examine changes in the costs associated with unplanned readmission between expansion states (AR, MD, NM, and WA) and non-expansion states (FL and GA). To estimate the differential effect of Medicaid expansion by race/ethnicity on the causes and cost of readmission, we added a time*treatment*race interaction. Multinomial logistic regression was performed to analyze the changes in readmission cause. Gamma log-link modeling was used to study changes in readmission costs for expansion compared to non-expansion states.

RESULTS

The final multinomial model showed an association between expanded Medicaid and the relative frequency of sepsis readmission for White patients. According to predictive margins, White patients in expansion states had an estimated increase of 3.3 percentage points in the share of readmissions for sepsis but not for White patients in non-expansion states. In contrast, non-White patients in expansion states had a decrease of 1.8 percentage points in the share of readmissions for sepsis. Overall, Medicaid expansion was associated with a net increase of 6.7 percentage points in the share of readmissions for sepsis among non-Hispanic Whites relative to all other groups. In the final gamma model, Medicaid expansion was associated with a decrease in readmission costs overall. According to predictive margins, the net cost reduction in expansion versus non-expansion states was an average of $2509.

CONCLUSIONS

Medicaid expansion is associated with an overall decrease in unplanned readmission costs and an increase among readmitted White patients in the likelihood of readmission for sepsis.

Health insurance and fertility among low-income, childless, single women: evidence from the ACA Medicaid expansions

Expansions of Medicaid family planning services have been associated with decreases in pregnancy rates. Access to a broader range of medical, non-family planning services may influence pregnancy rates as well if the increased exposure to medical services spills over to other kinds of behaviour. Using a difference-in-difference approach, I examine the impact of the Affordable Care Act (ACA) Medicaid expansions on the propensity of low-income, single women to become single mothers. Previous expansions of Medicaid family planning services allow us to also investigate the influence of access to other medical services (i.e. non-family planning). I find that although access to contraceptives is associated with a reduction in the propensity of becoming a single mother among adult, low-income women, medical services beyond access to contraceptives can provide additional impacts.

Medicaid Expansions and Private Insurance 'Crowd-Out' (1999-2019)

Recent Medicaid expansions have rekindled the debate around private insurance "crowd-out". Prior research is limited by short-time horizons and state-specific analyses. Our study overcomes these limitations by evaluating twenty years of Medicaid expansions across the entire United States. We obtain data from the U.S. Census Bureau for all U.S. states and D.C. for private insurance coverage rates of adults 18-64, for years 1999-2019. After estimating a naïve, staggered Two-Way Fixed Effects Difference-in-Differences regression model, we implement four novel econometric methods to diagnose and overcome threats of bias from staggered designs. We also test for pre-treatment differential trends and heterogenous effects over time. Our findings suggest that Medicaid expansion was associated with a 1.5%-point decline in private insurance rates (p < 0.001). We also observe significant heterogeneity over time, with estimates peaking four years after expansion. The importance of a 1-2%-point crowd-out, we leave for future research and debate.

Medicaid Expansion Lowered Uninsurance Rates Among Nonelderly Adults In The Most Heavily Redlined Areas

Medicaid expansion narrowed racial and ethnic disparities in health coverage, but few studies have explored differential impact by exposure to structural racism. We analyzed data on historical residential redlining in US metropolitan areas from the Mapping Inequality project, along with data on uninsurance from the American Community Survey, to test whether Medicaid expansion differentially reduced uninsurance rates among nonelderly adults exposed to historical redlining. Our difference-in-differences analysis compared uninsurance rates in Medicaid expansion and nonexpansion states both before (2009-13) and after (2015-19) the state option to expand Medicaid pursuant to the Affordable Care Act took effect in 2014. We found that Medicaid expansion had the greatest impact on lowering uninsurance rates in census tracts with the highest level of redlining. Within each redline category, there were no significant differences by race and ethnicity. Our results highlight the importance of considering contextual factors, such as structural racism, when evaluating health policies. States that opt not to expand Medicaid delay progress toward health equity in historically redlined communities.

The impact of access to prenatal health insurance for noncitizen women on child health

OBJECTIVE

To estimate the effects of prenatal public health insurance targeting noncitizens on the health of U.S.-born children of noncitizen mothers beyond birth outcomes.

DATA SOURCES AND STUDY SETTING

This paper uses the restricted version of the 1998-2014 National Health Interview Survey with state-level geographic identifiers.

STUDY DESIGN

The empirical strategy compares outcomes in states that adopted the Children's Health Insurance Plan (CHIP) Unborn Child Option with states that never adopted or adopted it at different times, controlling for differences in the pre-treatment period. I use a flexible event-study analysis to quantify the effects of the Unborn Child Option on noncitizen women's health insurance coverage, health care utilization, and their children's health.

DATA COLLECTION/EXTRACTION METHODS

All data are derived from pre-existing sources.

PRINCIPAL FINDINGS

The study finds that the impact of the Unborn Child Option is a 4.7%-point increase in public health insurance coverage (p < 0.01) and 0.48 more doctor's office visits (p < 0.1) annually among noncitizens of childbearing ages. Subsequently, the reform leads to a 7%-point rise in the rate of parents reporting their 4-6-year-old children are in "excellent" or "very good" health (p < 0.01). While no improvements are evident at birth and at younger ages, observed health improvements begin to appear by preschool age.

CONCLUSIONS

The study contributes to the literature by providing evidence that certain benefits of in-utero public health insurance targeting noncitizens may appear several years after birth, specifically around preschool age.

Effects of the affordable care Act's Medicaid expansion on health insurance coverage for individuals in same-sex couples

OBJECTIVE

To examine whether the Affordable Care Act's (ACA's) Medicaid expansions affected health insurance coverage for individuals in same-sex couples.

DATA SOURCES AND STUDY SETTING

We used data on adults aged 18-64 years in same-sex couples (n = 33,512) from the 2008-2018 American Community Survey (ACS).

STUDY DESIGN

To estimate the effect of the impact of the state Medicaid expansions under the ACA on health insurance coverage for sexual minorities, we utilize a standard difference-in-differences approach to leverage the variation across geography and time in expanding Medicaid.

DATA COLLECTION

Secondary and publicly available ACS data were obtained from IPUMS at the University of Minnesota.

PRINCIPAL FINDINGS

We find that Medicaid expansion significantly increased health insurance coverage among low-income men and women in same-sex couples by 4.9 (standard error [SE] = 1.75) and 6.5 (SE = 1.96) percentage points, respectively. We find increases in the likelihood of having Medicaid and reductions in private health insurance from an employer or privately purchased insurance. Effects on Medicaid take-up are consistently larger for low-income women in same-sex couples as compared to low-income men in same-sex couples.

CONCLUSIONS

We provide the first evidence on the relationship between state Medicaid expansions under the ACA and health insurance coverage among sexual minority adults, a group that has been understudied in past research. Our results confirm that sexual minority adults benefitted from the ACA's Medicaid expansions with respect to increased health insurance coverage.

Who did the ACA Medicaid expansion impact? Estimating the probability of being a complier

Who enrolled in Medicaid as a consequence of the Affordable Care Act (ACA)? Using the 2010-2017 American Community Survey, I estimate how characteristics relating to work status and race/ethnicity affect the probability that an individual will be a complier, defined as those induced by the ACA Medicaid expansion to obtain Medicaid coverage. Across all states, I find that part-time workers, not non-workers, are the most likely to be compliers. This finding is not consistent with certain notions that Medicaid participants are the "undeserving poor" - a sentiment that may have hindered efforts to expand Medicaid in certain states. Additionally, I find that in non-expansion states, many of which have high Black populations, the probability of being a complier is higher for Blacks than for other racial/ethnic groups, suggesting that Black people in non-expansion states would be the largest beneficiaries of any new expansions. This paper not only identifies the types of individuals who were already impacted by the expansion but also identifies which populations would benefit the most from subsequent expansions.

Medicaid reimbursement rates for primary care services and behavioral health outcomes

We study the effects of changing Medicaid reimbursement rates for primary care services on behavioral health outcomes-defined here as mental illness and substance use disorders. Medicaid enrollees are at elevated risk for these, and other, chronic conditions and are likely to have unmet treatment needs. We apply two-way fixed-effects regressions to survey data specifically designed to measure behavioral health outcomes over the period 2010-2016. We find that higher primary care reimbursement rates reduce mental illness and substance use disorders among non-elderly adult Medicaid enrollees, although we interpret findings for substance use disorders with some caution as they may be vulnerable to differential pre-trends. Overall, our findings suggest positive spillovers from a policy designed to target primary care services to behavioral health outcomes.

Effect of Medicaid Expansion on Health Insurance for Low-Income Nursing Home Aides

We examine how the Affordable Care Act Medicaid expansion affected the insurance coverage and the sources of coverage among low-income nursing home aides using the 2010-2019 American Community Survey data. Insurance coverage for low-income nursing home aides increased from about 60% to nearly 90% in expansion states but rose to only about 80% in nonexpansion states. Using a difference-in-differences regression design, we find that Medicaid expansion was associated with a 5.1 percentage-point increase in overall insurance coverage. Expansion states had a 12.2 percentage-point gain in Medicaid that was partially offset by a 6.4 percentage-point reduction in private insurance coverage. Our results show that ACA Medicaid expansion increased insurance coverage for low-income nursing home aides; however, there was substantial crowd-out of private insurance coverage in this population. Policymakers should consider expanding Medicaid while incentivizing affordable private health insurance options for low-income nursing home aides to improve insurance coverage.

Effects of Urban and Rural Resident Basic Medical Insurance on Healthcare Utilization Inequality in China

Objectives: This study aims to evaluate the effects of Urban and Rural Resident Basic Medical Insurance (URRBMI) integration on healthcare utilization and explore the contribution of URRBMI to healthcare utilization inequality among middle-aged and older adults. Methods: Using data from the China Health and Retirement Longitudinal Study (CHARLS) 2011-2018. The difference-in-difference model, concentration index (CI), and decomposition method were adopted. Results: The results suggested that the probability of outpatient visits and the number of outpatient visits had decreased by 18.2% and 10.0% respectively, and the number of inpatient visits had increased by 3.6%. However, URRBMI had an insignificant effect on the probability of inpatient visits. A pro-poor inequality for the treatment group was observed. The decomposition revealed that the URRBMI contributed to the pro-poor inequality in healthcare utilization. Conclusion: The findings suggest that URRBMI integration has decreased outpatient care utilization and improved the number of inpatient visits. While the URRBMI has improved healthcare utilization inequality, some challenges still exist. Comprehensive measures should be taken in the future.

Impacts of Publicly Funded Health Insurance for Adults on Children's Academic Achievement. SOUTHERN ECONOMIC JOURNAL 2023;89:860-884. [PMID: 38845841 PMCID: PMC11156232 DOI: 10.1002/soej.12614]

Empirical evidence demonstrates that publicly funded adult health insurance through the Affordable Care Act (ACA) has had positive effects on low-income adults. We examine whether the ACA's Medicaid expansions influenced child development and family functioning in low-income households. We use a difference-in-differences framework exploiting cross-state policy variation and focusing on children in low-income families from a nationally representative, longitudinal sample followed from kindergarten to fifth grade. The ACA Medicaid expansions improved children's reading test scores by approximately 2 percent (0.04 SD). Potential mechanisms for these effects within families are more time spent reading at home, less parental help with homework, and eating dinner together. We find no effects on children's math test scores or socioemotional skills.

Can Medicaid be a Solution to the Problem? Underinsurance in Medicaid Expansion Versus Non-Expansion States

The positive effects of Medicaid expansions have been extensively documented in the literature. However, it is not clear whether the reform has had an equally meaningful effect with respect to underinsurance, which is the state of having health insurance yet lacking adequate coverage or facing substantial financial risks upon usage of services. Based on a quasi-experimental difference-in-differences approach, we analyzed the data from a nationally representative sample to estimate the effect of Medicaid expansion on the probability of underinsurance among the non-elderly low-income adult population of the U.S. We found no evidence of significant changes in the likelihood of underinsurance due to Medicaid expansion during the first 4 years after the ACA implementation. However, a supplementary analysis of the longer-term impact (2018-2019) suggests that there might be a time lag between Medicaid expansion and its effect on underinsurance. It is important to realize that expansion of coverage alone may not be sufficient to protect millions of Americans, particularly those with low incomes, from underinsurance. It is, therefore, crucial for policymakers to build legislative frameworks that protect individuals from excessive healthcare expenses and prevent treatment avoidance or delay.

Health insurance coverage during the COVID-19 pandemic: The role of Medicaid expansion

Using data from the US Census Bureau's Household Pulse Survey, we analyzed the likelihood of loss of health insurance and enrollment into new health coverage during the early months of the COVID-19 pandemic. Loss of employment was associated with a significant increase in the likelihood of loss of health insurance and, specifically, an increase in the likelihood of employer-sponsored health insurance. However, individuals in Medicaid expansion states experienced a lower likelihood of loss of health insurance compared with individuals in nonexpansion states. At the same time, there was a statistically significant increase in Medicaid enrollment in expansion states, by 3.2 percentage points. Reemployment or acquiring employment was associated with a gain in health insurance coverage. During an economic downturn, eligibility, and coverage gaps leave many without affordable coverage options, and the pandemic will likely bring renewed attention to gaps in Medicaid coverage in nonexpansion states.

The impact of the repeal of the federal individual insurance mandate on uninsurance

The federal individual mandate of the Affordable Care Act, which required people to pay a tax penalty if they did not have health insurance, was repealed in 2019. However, some states implemented state-level insurance mandates which essentially replaced the federal mandate. I use nationally representative survey data from the 2015-19 Annual Social and Economic Supplement to the Current Population Survey to compare the probability of becoming newly uninsured among people living in states without state-level insurance mandates versus states with a mandate, before and after the 2019 repeal. In a sample of 214,821 lower-income, nonelderly adults, the repeal of the federal mandate was associated with a 0.5% point, or 24%, increase in the year-over-year probability of becoming newly uninsured. These results suggest that people respond to financial incentives when making insurance enrollment decisions. In the absence of a federal mandate, state-level mandates may reduce transitions to uninsurance.

The Affordable Care Act and regulation: Coverage effects of guaranteed issue and ratings reform

An important part of the Affordable Care Act (ACA) that has received relatively little research attention is regulatory reform in the small and non-group markets, particularly guaranteed issue and rating restrictions. In order to identify the effect of this part of the ACA, I use states that already had these policies before 2014 as a control group for states newly exposed to them under the ACA. Overall, the reforms do not have any effect in states that expanded Medicaid but are associated with a 1.64 percentage point (or 2.16%) increase in the probability of having health insurance coverage in states that did not expand Medicaid. Effects are seen across broad age range, and are strongest for those whose incomes are slightly above the Medicaid threshold and qualify them for the highest Marketplace subsidy levels.

Do non-citizens migrate for welfare benefits? Evidence from the Affordable Care Act Medicaid expansion

We explore if low-educated noncitizens, who have a considerably high uninsured rate, internally migrate to states with more generous public insurance benefits. We utilize the state-level variation in accessing Medicaid benefits and employ a difference-in-differences methodology that compares in-migration and out-migration rates of non-citizens in states that adopted Medicaid expansion, both before and after the policy implementation, to the outcomes of non-citizens in states that did not adopt the expansion. We find that interstate in-migration (out-migration) rates of Medicaid expansion states did not increase (decrease) relative to that of non-expansion states after the expansion.

INFORMATION GAPS AND HEALTH INSURANCE ENROLLMENT: Evidence from the Affordable Care Act Navigator Programs

We studied the impact of Affordable Care Act navigator programs on health insurance coverage, using the 80 percent cut in program funding under the Trump administration as a natural experiment. Our study design exploited county-level differences in the program prior to funding cuts. We did not find that cuts to the program significantly decreased rates of marketplace coverage or any health insurance coverage by 2019; however, our estimates could not rule out marketplace coverage declines of up to 2.7 percent (point estimate -1.3 percent, 95 percent CI: 2.7 percent to 0.1 percent), or total coverage declines of up to 1.8 percentage points (point estimate -0.8 percentage points or -1.2 percent, 95 percent CI: -1.8 to 0.2). Cuts to the navigator program significantly decreased marketplace coverage and total coverage among lower-income adults, and significantly decreased total coverage among adults under age 45, Hispanic adults, and adults who speak a language other than English at home. We found no significant impact of the cuts on Medicaid enrollment (95 percent CI: -1.9 percentage points to 0.5 percentage points); most uninsured people in the states we studied lived in locations that had not implemented Medicaid eligibility expansions. These findings suggest that before the funding cuts, navigators were helping underserved consumers obtain coverage.

Impact of Medicaid Expansion Under the Affordable Care Act on Receipt of Surgery for Breast Cancer

To determine whether Medicaid expansion under the 2010 Affordable Care Act affected rates of breast cancer surgery.

The Affordable Care Act Medicaid expansion: A difference-in-differences study of spillover participation in SNAP

The Affordable Care Act’s Medicaid expansion to individuals with adults under 138 percent of the federal poverty level led to insurance coverage for millions of Americans in participating states. This study investigates Medicaid expansion’s potential spillover participation in the Supplemental Nutrition Assistance Program (SNAP; formerly the Food Stamp Program). In addition to providing public insurance, the policy connects individuals to SNAP, affecting social determinants of health such as hunger. We use difference-in-differences regression to estimate the effect of the Medicaid expansion on SNAP participation among approximately 414,000 individuals from across the United States. The Current Population Survey is used to answer the main research question, and the SNAP Quality Control Database allows for supplemental analyses. Medicaid expansion produces a 2.9 percentage point increase (p = 0.002) in SNAP participation among individuals under 138 percent of federal poverty. Subgroup analyses find a larger 5.0 percentage point increase (p = 0.002) in households under 75 percent of federal poverty without children. Able-Bodied Adults Without Dependents (ABAWDs) are a category of individuals with limited access to SNAP. Although they are a subset of adults without children, we found no spillover effect for ABAWDs. We find an increase in SNAP households with $0 income, supporting the finding that spillover was strongest for very-low-income individuals. Joint processing of Medicaid and SNAP applications helps facilitate the connection between Medicaid expansion and SNAP. Our findings contribute to a growing body of evidence that Medicaid expansion does more than improve access to health care by connecting eligible individuals to supports like SNAP. SNAP recipients have increased access to food, an important social determinant of health. Our study supports reducing administrative burdens to help connect individuals to safety net programs. Finally, we note that ABAWDs are a vulnerable group that need targeted program outreach.

Impacts of the Affordable Care Act's Medicaid Expansion on Live Births

BACKGROUND

We hypothesize that the Affordable Care Act's (ACA) Medicaid expansion, which extended health insurance coverage to preconception, between-conception, and postconception periods for women meeting income eligibility guidelines, impacted the number of live births in the United States by increasing access to contraception and financial well-being. These impacts may differ by maternal socioeconomic and demographic characteristics.

METHODS

Using data from birth certificates aggregated to the state-year level and a difference-in-differences design, we estimated the association between Medicaid expansion and count of live births. We also examined whether associations differed by socioeconomic and demographic characteristics.

RESULTS

Overall, Medicaid expansion was not meaningfully associated with the count of births (difference-in-differences ß = 0.002; 95% confidence interval [CI] = -0.010, 0.015). However, among certain groups, Medicaid expansion was associated with meaningful changes in the count of live births, though all confidence intervals included the null value. The estimate of the relation between Medicaid expansion and the count of live births was -0.025 (95% CI = -0.052, 0.001) for those ages 18-24 years; -0.078 (95% CI = -0.231, 0.075) for those who were married, and -0.035 (95% CI = -0.104, 0.034) for those who were unmarried.

CONCLUSIONS

Despite its potential to impact live births, our results indicate that the ACA's Medicaid expansion was not, in general, associated with live births of US residents of reproductive age. However, for younger, married, and unmarried women, the magnitude of estimates supports the hypothesis of a potentially meaningful effect of Medicaid expansions on live births.

Association of Medicaid Expansion With Neuraxial Labor Analgesia Use in the United States: A Retrospective Cross-Sectional Analysis

BACKGROUND

The Affordable Care Act has been associated with increased Medicaid coverage for childbirth among low-income US women. We hypothesized that Medicaid expansion was associated with increased use of labor neuraxial analgesia.

METHODS

We performed a cross-sectional analysis of US women with singleton live births who underwent vaginal delivery or intrapartum cesarean delivery between 2009 and 2017. Data were sourced from births in 26 US states that used the 2003 Revised US Birth Certificate. Difference-in-difference linear probability models were used to compare changes in the prevalence of neuraxial labor analgesia in 15 expansion and 11 nonexpansion states before and after Medicaid expansion. Models were adjusted for potential maternal and obstetric confounders with standard errors clustered at the state level.

RESULTS

The study sample included 5,703,371 births from 15 expansion states and 5,582,689 births from 11 nonexpansion states. In the preexpansion period, the overall rate of neuraxial analgesia in expansion and nonexpansion states was 73.2% vs 76.3%. Compared with the preexpansion period, the rate of neuraxial analgesia increased in the postexpansion period by 1.7% in expansion states (95% CI, 1.6-1.8) and 0.9% (95% CI, 0.9-1.0) in nonexpansion states. The adjusted difference-in-difference estimate comparing expansion and nonexpansion states was 0.47% points (95% CI, -0.63 to 1.57; P = .39).

CONCLUSIONS

Medicaid expansion was not associated with an increase in the rate of neuraxial labor analgesia in expansion states compared to the change in nonexpansion states over the same time period. Increasing Medicaid eligibility alone may be insufficient to increase the rate of neuraxial labor analgesia.

Longitudinal trends in enrollees' employment and student status after Medicaid expansion

BACKGROUND

Medicaid community engagement requirements previously received federal approval in 12 states, despite limited data on their impact on enrollees' employment-related activities. Our objective was to assess longitudinal changes in enrollees' employment and student status after implementation of Michigan's Medicaid expansion.

METHODS

Longitudinal telephone survey of Michigan Medicaid expansion enrollees in 2016 (response rate [RR] = 53.7%), 2017 (RR = 83.4%), and 2018 (N = 2,608, RR = 89.4%) serially assessing self-reported employment or student status. Survey responses were benchmarked against statewide changes in assessed similar low-income adults in the U.S. Census Bureau Current Population Survey. We used mixed models with individual random effects to assess changes in the proportion of enrollees who were employed or students by year.

RESULTS

Most respondents had incomes < 100% FPL (61.7% with 0-35% of the federal poverty level [FPL], 22.9% with 36-99% FPL, and 15.4% with 100-133% FPL), 89.3% had at least a high school diploma/equivalent, and they ranged in age (39.6% age 19-34, 34.5% age 35-50, 25.9% age 51-64). Employment or student status increased significantly among Michigan Medicaid expansion respondents, from 54.5% in 2016 to 61.4% in 2018 (P < 0.001), including among those with a chronic condition (47.8% to 53.8%, P < 0.001) or mental health/substance use disorder (48.5% to 56.0%, P < 0.001). In contrast, the statewide proportion of low-income non-elderly adults who were employed or students did not change significantly (from 42.7% in 2016 to 46.0% in 2018, P = 0.57).

CONCLUSIONS

Medicaid expansion, absent a community engagement requirement, was associated with increased employment and related activities. The role of Medicaid in providing safety-net coverage to individuals during times of economic stress is likely to grow.

Health insurance and subjective well-being: Evidence from two healthcare reforms in the United States

We study the role of access to health insurance coverage as a determinant of individuals' subjective well-being (SWB) by analyzing large-scale healthcare reforms in the United States. Using data from the Behavioral Risk Factor Surveillance System and Panel Study of Income Dynamics, we find that the 2006 Massachusetts reform and 2014 Affordable Care Act Medicaid expansion improved the overall life satisfaction of Massachusetts residents and low-income adults in Medicaid expansion states, respectively. The results are robust to various sensitivity and falsification tests. Our findings imply that access to health insurance plays an important role in improving SWB. Without considering psychological benefits, the actual benefits of health insurance may be underemphasized.

Effects of Virginia’s 2019 Medicaid Expansion on Health Insurance Coverage, Access to Care, and Health Status

Virginia expanded Medicaid under the Affordable Care Act beginning in January 2019, which substantially increased income eligibility up to 138% of the federal poverty level (FPL) for both childless adults and parents. In this study, we examined the effects of Virginia’s Medicaid expansion in 2019 on health insurance coverage, access to care, and health status by employing a difference-in-differences and a synthetic control design. The study included data on health insurance from the 2016–2020 American Community Survey (ACS) and data on access to care and health status come from the 2016–2020 Behavioral Risk Factors Surveillance System (BRFSS). The samples from ACS and BRFSS were limited to non-elderly adults with income below 138% of the FPL. Separate models were estimated for individuals below 100% of FPL, and those within 100–138% of FPL. The Virginia Medicaid expansion was associated with a 9–11 percentage-point increase in Medicaid coverage rate and a 7–8 percentage-point increase in the insured rate among individuals below 100% FPL, in the first two years of expansion. There was a larger increase in Medicaid coverage among individuals within 100–138% of FPL which also led to a larger increase in the insured rate in 2020. Both income groups showed no changes in private coverage after the expansion in Virginia. We also found a decline in delaying necessary medical visits due to cost for individuals below 100% FPL in 2019 and for individuals within 100–138% FPL in 2020. There was overall no discernable change in health status outcomes. Virginia’s 2019 Medicaid expansion substantially increased insurance coverage among poor adults with suggestive early evidence for improved access. The findings highlight the missed opportunity for other states that have not yet decided to expand their Medicaid programs to improve coverage and access among their low-income individuals.

Health insurance coverage among American Indians and Alaska Natives in the context of the Affordable Care Act

Objectives: American Indians and Alaska Natives (AI/AN) have a unique healthcare system uniquely interwoven with the Affordable Care Act (ACA). The aim of this study is to document changes in health insurance among AI/AN adults before and after implementation of the ACA.Design: We used data from the American Community Survey from 2008 to 2016 to examine trends in health insurance. We compared to Non-Hispanic Whites and stratified AI/AN adults with and without Indian Health Service (IHS) coverage. We used multivariate regression to evaluate the probability of health insurance post-ACA and included time period and subgroup interaction terms.Results: Public and private health insurance coverage increased post-ACA by 3.17 and 1.24 percentage points, respectively, but the percent uninsured remained high (37.7% of those with IHS coverage and 19.2% of those without). AI/AN in Medicaid Expansion states had a significantly greater percentage point (pp) increase in public insurance (6.31 pp, 95% CI 5.04-7.59) than AI/AN in non-expansion states (p < 0.001). There was a greater increase in private coverage among AI/AN without IHS compared to AI/AN with IHS coverage (p = 0.002).Conclusions: Despite improvements in healthcare insurance coverage for AI/AN, substantial disparities remain. The improvements appeared to be largely driven by Medicaid Expansion. Without specific considerations for AI/AN, future healthcare reforms could intensify health injustices and inequities they face.

Effects of parental public health insurance eligibility on parent and child health outcomes

Many states expanded their Medicaid programs to low-income adults under the Affordable Care Act (ACA). These expansions increased Medicaid coverage among low-income parents and their children. Whether these improvements in coverage and healthcare use lead to better health outcomes for parents and their children remains unanswered. We used longitudinal data on a large, nationally representative cohort of elementary-aged children from low-income households from 2010 to 2016. Using a difference-in-differences approach in state Medicaid policy decisions, we estimated the effect of the ACA Medicaid expansions on parent and child health. We found that parents' self-reported health status improved significantly post-expansion in states that expanded Medicaid through the ACA by 4 percentage points (p < 0.05), a 4.7% improvement. We found no significant changes in children's use of routine doctor visits or parents' assessment of their children's health status. We observed modest decreases in children's body mass index (BMI) of about 2% (p < 0.05), especially for girls.

A Quasi-Experimental Study of Medicaid Expansion and Urban Mortality in the American Northeast

Objectives: To investigate the association of state-level Medicaid expansion and non-elderly mortality rates from 1999 to 2018 in Northeastern urban settings.

Methods: This quasi-experimental study utilized a synthetic control method to assess the association of Medicaid expansion on non-elderly urban mortality rates [1999–2018]. Counties encompassing the largest cities in the Northeastern Megalopolis (Washington D.C., Baltimore, Philadelphia, New York City, and Boston) were selected as treatment units (n = 5 cities, 3,543,302 individuals in 2018). Cities in states without Medicaid expansion were utilized as control units (n = 17 cities, 12,713,768 individuals in 2018).

Results: Across all cities, there was a significant reduction in the neoplasm (Population-Adjusted Average Treatment Effect = −1.37 [95% CI −2.73, −0.42]) and all-cause (Population-Adjusted Average Treatment Effect = −2.57 [95%CI −8.46, −0.58]) mortality rate. Washington D.C. encountered the largest reductions in mortality (Average Treatment Effect on All-Cause Medical Mortality = −5.40 monthly deaths per 100,000 individuals [95% CI −12.50, −3.34], −18.84% [95% CI −43.64%, −11.67%] reduction, p = < 0.001; Average Treatment Effect on Neoplasm Mortality = −1.95 monthly deaths per 100,000 individuals [95% CI −3.04, −0.98], −21.88% [95% CI −34.10%, −10.99%] reduction, p = 0.002). Reductions in all-cause medical mortality and neoplasm mortality rates were similarly observed in other cities.

Conclusion: Significant reductions in urban mortality rates were associated with Medicaid expansion. Our study suggests that Medicaid expansion saved lives in the observed urban settings.

Crowd-Out and Emergency Department Utilization

When consumers gain Medicaid, their cost of healthcare changes. The direction of this change determines how utilization changes. The previously uninsured see a stark decrease in the price of primary care after gaining public insurance. Due to charity care, they may face an increase in the price of emergency department care. The previously insured see a reduction in emergency department prices and decreased access to primary care. We examine the impact of the prior insurance status of the newly publicly insured on substitution between healthcare. We base our identification on California's LIHP and ACA Medicaid expansions. One challenge we face is estimating crowd-out. We use machine learning techniques to predict prior insurance status based on observable covariates in cross-sectional data. We find an increase in emergency department utilization caused entirely by those crowded-out whose access to primary care has decreased. We find the opposite utilization patterns for the previously uninsured.

Health Power Resources Theory: A Relational Approach to the Study of Health Inequalities

Link and Phelan's pioneering 1995 theory of fundamental causes urged health scholars to consider the macro-level contexts that "put people at risk of risks." Allied research on the political economy of health has since aptly demonstrated how institutions contextualize risk factors for health. Yet scant research has fully capitalized on either fundamental cause or political economy of health's allusion to power relations as a determinant of persistent inequalities in population health. I address this oversight by advancing a theory of health power resources that contends that power relations distribute and translate the meaning (i.e., necessity, value, and utility) of socioeconomic and health-relevant resources. This occurs through stratification, commodification, discrimination, and devitalization. Resurrecting historical sociological emphases on power relations provides an avenue through which scholars can more fully understand the patterning of population health and better connect the sociology of health and illness to the central tenets of the discipline.

The effect of Affordable Care Act Medicaid expansions on foster care admissions

Recent papers have documented positive externalities of Medicaid expansions on several non-health related variables, such as crime, financial stress, child support, and child abuse. In this paper, we investigate the relationship between access to public health insurance and foster care admissions following state decisions to expand Medicaid coverage after the Affordable Care Act. Over 70% of all foster care admissions are related to child abuse incidents, which have been found to decrease following the Medicaid expansions. Our results suggest that the Medicaid expansions are associated with a large decrease in foster care admissions, driven by neglect incidents.

The Affordable Care Act's Coverage Impacts in the Trump Era

The 2016 US presidential election created uncertainty about the future of the Affordable Care Act (ACA) and led to postponed implementation of certain provisions, reduced funding for outreach, and the removal of the individual mandate tax penalty. In this article, we estimate how the causal impact of the ACA on insurance coverage changed during 2017 through 2019, the first 3 years of the Trump administration, compared to 2016. Data come from the 2011–2019 waves of the American Community Survey (ACS), with the sample restricted to non-elderly adults. Our model leverages variation in treatment intensity from state Medicaid expansion decisions and pre-ACA uninsured rates. We find that the coverage gains from the components of the law that took effect nationally—such as the individual mandate and regulations and subsidies in the private non-group market—fell from 5 percentage points in 2016 to 3.6 percentage points in 2019. In contrast, the coverage gains from the Medicaid expansion increased in 2017 (7.0 percentage points) before returning to the 2016 level of coverage gains in 2019 (5.9 percentage points). The net effect of the ACA in expansion states is a combination of these trends, with coverage gains falling from 10.8 percentage points in 2016 to 9.6 percentage points in 2019.

Associations of Medicaid Expansion With Access to Care, Severity, and Outcomes for Acute Ischemic Stroke

BACKGROUND

Multiple states have not expanded Medicaid under the Affordable Care Act, resulting in higher uninsured rates in states with high stroke burdens. This study aimed to evaluate the association of Medicaid expansion with changes in health insurance coverage, severity of presentation, access to care, and outcomes among patients with acute ischemic stroke.

METHODS

A retrospective, difference-in-differences analysis of Get With The Guidelines-Stroke registry data. The study population comprised first-time ischemic stroke admissions from 2012 to 2018 for patients aged 19 to 64 in 45 states (27 that expanded Medicaid and 18 that did not). A probable low-income cohort was defined based on having Medicaid, no insurance/self-pay, or undocumented insurance. Outcomes analyzed were indicators of health insurance status, stroke severity, use of emergency services, time to acute care, in-hospital mortality, receipt of rehabilitation, discharge disposition, and level of disability.

RESULTS

In the starting population (N=342 765), Medicaid-covered stroke admissions rose from 12.2% to 18.1% in expansion states and from 10.0% to only 10.6% in nonexpansion states, while uninsured admissions declined from 15.0% to 6.7% in expansion states and from 24.0% to 19.2% in nonexpansion states. In the low-income cohort (N=95 086; 28% of starting population), Medicaid expansion was associated with increased odds of discharge to a skilled nursing facility (adjusted odds ratio, 1.33 [95% CI, 1.12-1.59]) and transfer to any rehabilitation facility among those eligible (adjusted odds ratio, 1.24 [95% CI, 1.08-1.41]) and lower odds of discharge home (adjusted odds ratio, 0.89 [95% CI, 0.80-0.98]). Expansion was not associated with any other outcomes.

CONCLUSIONS

Medicaid expansion is associated with fewer uninsured hospitalizations for acute ischemic stroke and increased rehabilitation at skilled nursing facilities. More targeted interventions may be needed to improve other stroke outcomes in the low-income US population. Future research should evaluate the impact of health care reform on primary stroke prevention.

The Affordable Care Act Increased Medicaid Coverage Among Former Foster Youth

Youth aging out of the foster care system in the US are a vulnerable population. When in foster care, youth are eligible for their state's Medicaid program, but they lose eligibility when they age out of foster care. The Affordable Care Act (ACA) has the potential to address some of the health care needs of former foster youth through the Medicaid eligibility expansion to low-income adults and by extending Medicaid eligibility up to age twenty-six for former foster youth. Using the 2011-18 National Youth in Transition Database, we found that Medicaid expansion increased Medicaid coverage among former foster youth by 10.1 percentage points, and the age extension increased coverage by 3.4 percentage points. There is suggestive evidence of positive spillovers for both policies. Our findings imply that the ACA improved Medicaid coverage among former foster youth, with the largest effects from Medicaid expansion. The modest effects of the Medicaid age extension may imply a need to revise enrollment, recertification, outreach, and eligibility determination processes to further increase Medicaid coverage among former foster youth.

The Relationship Between Unemployment and Health Insurance Coverage: Before and After the Affordable Care Act's Coverage Expansions

OBJECTIVE

The objective of this study was to determine whether the Affordable Care Act's (ACA) major coverage expansions mitigated the impact of unemployment on health insurance coverage status.

DATA SOURCE

A 2011-2019 versions of the American Community Survey developed by the University of Minnesota Integrated Public Use Microdata Series program.

RESEARCH DESIGN

We use difference-in-difference-in-differences (ie, triple difference) regressions to compare changes in the short-run impacts of local unemployment rates before and after the ACA.

PRINCIPAL FINDINGS

Before the ACA, rises in local unemployment were associated with uninsurance due to losses in private coverage (ie, both nongroup and employer sponsored).Following the ACA's full implementation, the link between employment and coverage was attenuated by access to publicly subsidized qualified health plans on the ACA's nongroup market, and enhanced access to Medicaid in states that expanded. Our findings suggest protections from unemployment-linked uninsured spells are largest in states that expanded Medicaid.

CONCLUSIONS

Expanded access to coverage under the ACA could mitigate the adverse effects on insurance status and access to care historically linked to job loss. However, should the ACA be repealed, many households stand to lose their ability to turn to Medicaid or subsidized nongroup coverage as safety-net resources to offset the burdens of job loss.

Examination of the Association Between Access to Care and Lung Cancer Screening Among High-Risk Smokers

Objective: The purpose of this study was to examine the influence of access to care on the uptake of low-dose computed tomography (LDCT) lung cancer screening among a diverse sample of screening-eligible patients. Methods: We utilized a cross-sectional study design. Our sample included patients evaluated for lung cancer screening at a large academic medical center (AMC) between 2015 and 2017 who met 2013 USPSTF guidelines for LDCT screening eligibility. The completion of LDCT screening (yes, no) was the primary dependent variable. The independent variable was access to care (insurance type, living within the AMC service area). We utilized binary logistic regression analyses to examine the influence of access to care on screening completion after adjusting for demographic factors (age, sex, race) and smoking history (current smoking status, smoking pack-year history). Results: A total of 1,355 individuals met LDCT eligibility criteria, and of those, 29.8% (n = 404) completed screening. Regression analysis results showed individuals with Medicaid insurance (OR, 1.51; 95% CI, 1.03-2.22), individuals living within the AMC service area (OR, 1.71; 95% CI, 1.21-2.40), and those aged 65-74 years (OR, 1.49; 95% CI, 1.12-1.98) had higher odds of receiving LDCT lung cancer screening. Lower odds of screening were associated with having Medicare insurance (OR, 0.30; 95% CI, 0.22-0.41) and out-of-pocket (OR, 0.27; 95% CI, 0.15-0.47). Conclusion: Access to care was independently associated with lowered screening rates. Study results are consistent with prior research identifying the importance of access factors on uptake of cancer early detection screening behaviors.

Medicaid Expansion Reduced Uninsured Surgical Hospitalizations And Associated Catastrophic Financial Burden

An important function of health insurance is protecting enrollees from excessively burdensome charges for unanticipated medical events. Unexpected surgery can be financially catastrophic for uninsured people. By targeting the low-income uninsured population, Medicaid expansion had the potential to reduce the financial risks associated with these events. We used two data sources (state-level data for forty-four states and patient-level data for four states) to estimate the association of Medicaid expansion with uninsured surgical hospitalizations among nonelderly adults. Uninsured surgery cases were typically admitted through the emergency department-often for common emergency procedures-and 99 percent of them were estimated to be associated with financially catastrophic visit charges. We found that Medicaid expansion was associated with reductions in both the share (6.20 percent) and the population rate (7.85 per 10,000) of uninsured surgical discharges in expansion versus nonexpansion states. Our estimates suggest that in 2019 alone, adoption of Medicaid expansion in nonexpansion states could have prevented more than 50,000 incidences of catastrophic financial burden resulting from uninsured surgery.

Insurance expansions and hospital utilization: Relabeling and reabling?

The 2010 Patient Protection & Affordable Care Act (ACA) significantly expanded access to private and public health insurance for low-income individuals through income-based subsidies and income-based eligibility expansions, respectively. In this paper, we use the universe of hospitals from 2009 to 2015 to characterize how these expansions affected the financing of hospital visits, along with price, utilization, and potential spillovers in the quality of care. The insurance coverage expansions generated a shift in the composition of payers and a modest increase in the utilization of hospital outpatient services. While concerns have been raised that these shifts in utilization could cause negative spillovers to the already insured population (e.g., Medicare enrollees), we find no significant change in the quality of care experienced by those already insured. The primary result of both federally funded insurance expansions was to increase the profits generated and prices charged by the hospitals providing such services.

Geographic variation in Part B reimbursement and physician offsetting behavior: a physician matching approach

Historically, Medicare has operated under the assumption that providers respond to reductions in reimbursement through increased provision of services in an effort to offset declining practice revenue; however, some recent empirical work examining fee reductions has found evidence of either small offsetting effects or reductions in the quantity supplied. Using a distance matching approach that matches practices to nearby practices that are subject to different reimbursement rates, we find overall evidence in support of Medicare's offsetting assumption collectively for all services and for evaluation and management services. We also find evidence consistent with a traditional volume response for imaging and testing services.

Medicaid expansion and the mental health of college students

Reported mental health problems have risen dramatically among US college students over time, as has treatment for these problems. We examine the effect of state-level Medicaid expansion following the 2014 implementation of the Affordable Care Act on the diagnosis of mental health conditions, psychotropic prescription drug use, and the mental health status of a national sample of college students. We find that students from disadvantaged backgrounds are more likely to report being on public insurance after 2014 in expansion states relative to non-expansion states, while more advantaged students do not see this increase. Both diagnosis of common mental health conditions and psychotropic drug use increase following expansion for disadvantaged students relative to advantaged ones, which translates into an elimination of the pre-expansion gap in these outcomes by family background in expansion states. However, in contrast to some recent work on Medicaid expansion and mental health, we do not find that these changes are associated with improvements in self-reported mental health status. We also do not find that Medicaid expansion has affected risky health behaviors or academic outcomes.

The Impact of the Affordable Care Act Medicaid Expansions on the Sources of Health Insurance Coverage of Undergraduate Students in the United States

This article examines how the Affordable Care Act Medicaid expansions affected the sources of health insurance coverage of undergraduate students in the United States. We show that the Affordable Care Act expansions increased the Medicaid coverage of undergraduate students by 5 to 7 percentage points more in expansion states than in nonexpansion states, resulting in 17% of undergraduate students in expansion states being covered by Medicaid postexpansion (up from 9% prior to the expansion). In contrast, the growth in employer and private direct coverage was 1 to 2 percentage points lower postexpansion for students in expansion states compared with nonexpansion states. Our findings demonstrate that policy efforts to expand Medicaid eligibility have been successful in increasing the Medicaid coverage rates for undergraduate students in the United States, but there is evidence of some crowd out after the expansions-that is, some students substituted their private and employer-sponsored coverage for Medicaid.

The effect of subsidized childcare on the supply of informal care: Evidence from public kindergarten provision in the US

For informal caregivers in certain demographic groups, the tradeoff between childcare and informal care may be as significant as the tradeoff between informal care and labor supply. We shed light on this tradeoff empirically, by combining detailed time use data with a natural experiment created by differential access to publicly funded kindergarten across households and states. We find a substantial elasticity between informal care supply and kindergarten access, especially for female carers. In fact, for women, kindergarten access appears to largely increase their care supply rather than labor supply.

How Much Do Outside Options Matter? The Effect of Subsidized Health Insurance on Social Security Disability Insurance Benefit Receipt

New government health insurance programs may affect participation in existing safety-net benefits that provide health insurance as a secondary aim. We examine whether the outside options for health insurance made available by the Affordable Care Act affected Social Security Disability Insurance (DI) application decisions. Using the universe of U.S. individual income tax records spanning 2007-2016, we first estimate the effect of Medicaid expansions using a state difference-in-differences identification strategy, but find small and statistically insignificant estimates. However, when we estimate the effect of being eligible for high vs. low Marketplace subsidies based on geography, we find some evidence consistent with subsidies increasing DI claiming among those with prior access to Employer Sponsored Insurance, and decreasing DI claiming otherwise. Overall, we find suggestive evidence that outside options for health insurance do matter, though magnitudes are small and results are statistically precise only for Marketplace coverage.

Income Responses to the Affordable Care Act: Evidence from a Premium Tax Credit Notch

We examine responses to the ACA subsidy for Marketplace health insurance in the first year of subsidy availability. Drawing on federal tax data and focusing on a notch in the schedule where eligibility is lost, we document that taxpayers lowered their income to remain eligible for the subsidy. The observed bunching is modest relative to the size of the notch, which, consistent with larger responses we detect in additional analyses among certain subgroups, is likely explained by significant optimization frictions. Finally, we find suggestive evidence that increased deductions drive some of the response, while reduced labor supply also plays a role.

Effect of Medicaid Expansions on HIV Diagnoses and Pre-Exposure Prophylaxis Use

INTRODUCTION

Increased insurance coverage and access to health care can increase identification of undiagnosed HIV infection and use of HIV prevention services such as pre-exposure prophylaxis. This study investigates whether the Medicaid expansions facilitated by the Affordable Care Act had these effects.

METHODS

A difference-in-differences design was used to estimate the effects of the Medicaid expansions using data on HIV diagnoses per 100,000 population, awareness of HIV status, and pre-exposure prophylaxis use. The analyses involved first calculating differences in new diagnoses and pre-exposure prophylaxis use before and after the expansions and then comparing these differences between treatment counties (i.e., all counties in states that expanded Medicaid) and control counties (i.e., all counties in states that did not expand Medicaid). Further analyses to investigate mechanisms addressed associations with HIV incidence, rates of sexually transmitted infections, and substance use. Analyses were conducted between August 2019 and July 2020.

RESULTS

Medicaid expansions were associated with an increase in HIV diagnoses of 0.508 per 100,000 population, or 13.9% (p=0.037), particularly for infections contracted via injection drug use and among low-income, rural counties with a high share of pre-Affordable Care Act uninsured rates that were most likely to be affected by the expansions. In addition, Medicaid expansions were associated with improvements in the knowledge of HIV status and pre-exposure prophylaxis use. There was no impact of the expansions on incident HIV, substance use, or sexually transmitted infection rates with the exception of gonorrhea, which decreased after the expansions. Altogether, these results suggest that the changes in new HIV diagnoses, awareness of HIV status, and pre-exposure prophylaxis were not simply because of a higher incidence or an increase in infection risk.

CONCLUSIONS

Medicaid expansions were associated with increases in the percentage of people living with HIV who are aware of their status and pre-exposure prophylaxis use. Expanding public health insurance may be an avenue for curbing the HIV epidemic.

Heterogeneous Effects of Affordable Care Act Medicaid Expansions Among Women with Dependent Children by State-Level Pre-Expansion Eligibility

Objectives: This study explores the heterogeneity in effects of the 2014 Affordable Care Act (ACA) Medicaid expansions on insurance coverage, health care access, and health status of low-income women with dependent children by pre-expansion state-level income eligibility. Materials and Methods: We employ a quasiexperimental difference-in-differences design comparing outcome changes in Medicaid expansion states to nonexpansion states. We estimate effects separately for three groups of expansion states based on pre-expansion (2013) parent income eligibility: low pre-expansion eligibility (<90% of federal poverty level [FPL]), high eligibility (90% to <138% FPL), and full eligibility (≥138% FPL). Study samples include women with dependent children below 138% FPL from the 2011 to 2018 American Community Survey for the insurance outcomes, and from the 2011 to 2018 Behavioral Risk Surveillance System for the access and health outcomes. Results: There is stark heterogeneity in changes of health insurance and health care access by pre-expansion income eligibility levels. In comparison to Medicaid non-expansion states, there are large increases in insured rate (9 percentage-points) and Medicaid coverage (16 percentage-points) in expansion states with low pre-expansion eligibility. Insurance changes are much smaller in states with high or full pre-expansion eligibility. Changes in access largely mirror those in coverage. There are no significant changes in health status regardless of pre-expansion eligibility. Conclusions: The ACA Medicaid expansions increased coverage and access for low-income women with dependent children primarily in states with low pre-expansion parent eligibility, and therefore, reduced differences in these outcomes between expansion states.

Inequality in health insurance coverage before and after the Affordable Care Act

This study examines how the Affordable Care Act (ACA) affected income related inequality in health insurance coverage in the United States. Analyzing data from the American Community Survey (ACS) from 2010 through 2018, we apply difference-in-differences, and triple-differences estimation to the Recentered Influence Function OLS estimation. We find that the ACA reduced inequality in health insurance coverage in the United States. Most of this reduction was a result of the Medicaid expansion. Additional decomposition analysis shows there was little change in inequality of coverage through an employer plan, and a decrease in inequality for coverage through direct purchase of health insurance. These results indicate that the insurance exchanges also contributed to declining inequality in health insurance coverage.

Adopting “Difference-in-Differences” Method to Monitor Crop Response to Agrometeorological Hazards with Satellite Data: A Case Study of Dry-Hot Wind

Rapid changing climate has increased the risk of natural hazards and threatened global and regional food security. Near real-time monitoring of crop response to agrometeorological hazards is fundamental to ensuring national and global food security. However, quantifying crop responses to a specific hazard in the natural environment is still quite challenging, especially over large areas, due to the lack of tools to separate the independent impact of the hazard on crops from other confounding factors. In this study, we present a general difference-in-differences (DID) framework to monitor crop response to agrometeorological hazards at near real-time using widely accessible remotely sensed vegetation indices (VIs). To demonstrate the effectiveness of the DID framework, we applied it in quantifying the dry-hot wind impact on winter wheat in northern China as a case study using the VIs calculated from the MODIS data. The monitoring results for three years with varying severity levels of dry-hot events (i.e., 2007, 2013, and 2014) demonstrated that the framework can effectively detect winter wheat growing areas affected by dry-hot wind hazards. The estimated damage shows a notable relationship (R2 = 0.903, p < 0.001) with the dry-hot wind intensity calculated from meteorological data, suggesting the effectiveness of the method when field data on a large scale is not available for direct validation. The main advantage of this method is that it can effectively isolate the impact of a specific hazard (i.e., dry-hot wind in the case study) from the mixed signals caused by other confounding factors. This general DID framework is very flexible and can be easily extended to other natural hazards and crop types with proper adjustment. Not only can this framework improve the crop yield forecast but also it can provide near real-time assessment for farmers to adapt their farming practice to mitigate impacts of agricultural hazards.