Interventions to Increase Affordable Care Act Marketplace Enrollment: A Systematic Review And Meta-Analysis.

Over 10 million uninsured individuals are eligible for subsidized health insurance coverage through the Affordable Care Act (ACA) marketplaces, and millions more were projected to become eligible with the end of the federal COVID-19 Public Health Emergency in 2023. Individual studies on behaviorally informed interventions designed to encourage enrollment suggest that some are more effective than others. This study summarizes evidence on the efficacy of these interventions and suggests which administrative burdens might be most relevant for potential enrollees. Published and unpublished studies were identified through a systematic review of studies assessing the impact of behaviorally informed interventions on ACA marketplace enrollment from 2014 to 2022. Thirty-four studies comprising over 18 million participants were included (32 randomized controlled trials and 2 quasiexperimental studies). At the time of data extraction, 8 were published. Twenty-seven of the studies qualified for inclusion in a meta-analysis, which found that the average rate of enrollment was about 1 percentage point higher for those who received an intervention (0.009, P < 0.001), a 24% increase relative to control households; for every 1000 people who receive an intervention, that would correspond to about 9 additional enrollees. When stratifying by intervention intensity, support-based interventions increased enrollment by 2 percentage points (0.020, P = 0.004), while information-based interventions increased enrollment by 0.6 percentage points (0.006, P < 0.001). The meta-analysis found that behaviorally informed interventions can increase ACA marketplace enrollment. Interventions aimed at alleviating compliance costs by providing enrollment support were about three times as effective as information alone.

Did the Affordable Care Act Promote Racial Equity in Pregnancy-Related Health? A Scoping Review.

In the United States, there are profound and persistent racial and ethnic disparities in pregnancy-related health, emphasizing the need to promote racial health equity through public policy. There is evidence that the Affordable Care Act (ACA) increased health insurance coverage, access to health care, and health care utilization, and may have affected some pregnancy-related health outcomes (eg, preterm delivery). It is unclear, however, whether these impacts on pregnancy-related outcomes were equitably distributed across race and ethnicity. Thus, the objective of this study was to fill that gap by summarizing the peer-reviewed evidence regarding the impact of the ACA on racial and ethnic disparities in pregnancy-related health outcomes. The authors conducted a scoping review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR), using broad search terms to identify relevant peer-reviewed literature in PubMed, Web of Science, and EconLit. The authors identified and reviewed n = 21 studies and found that the current literature suggests that the ACA and its components were differentially associated with contraception-related and fertility-related outcomes by race/ethnicity. Literature regarding pregnancy health, birth outcomes, and postpartum health, however, was sparse and mixed, making it difficult to draw conclusions regarding the impact on racial/ethnic disparities in these outcomes. To inform future health policy that reduces racial disparities, additional work is needed to clarify the impacts of contemporary health policy, like the ACA, on racial disparities in pregnancy health, birth outcomes, and postpartum health.

Inclusion of People With Disabilities in Community Health Needs Assessments in Florida, United States.

Community health needs assessments (CHNAs) play a crucial role in identifying health needs of communities. Yet, unique health needs of people with disabilities (PWDs) are often underrecognized in public health practice. In 2010, the Patient Protection and Affordable Care Act (ACA) required the implementation of standardized data collection guidelines, including disability status, among federal agencies. The extent to which guidance from ACA and the U.S. Centers for Disease Control and Prevention has impacted disability inclusion in CHNAs is unknown. This study used a content analysis approach to review CHNAs conducted by local health councils and the top 11 nonprofit hospitals in Florida (n = 77). We coded CHNAs based on mentioning disability in CHNA reports, involving disability-related stakeholders, and incorporating data on disability indicators. Findings indicate that PWDs are widely not included in CHNAs in Florida, emphasizing the need for equitable representation and comprehensive understanding of PWDs in community health planning.

Impacts of the Affordable Care Act Medicaid Expansion on Mental Health Treatment Among Low-income Adults Across Racial/Ethnic Subgroups, 2010-2017.

This study examines whether the Affordable Care Act (ACA) Medicaid expansion (ME) was associated with changes in racial/ethnic disparities in insurance coverage, utilization, and quality of mental health care among low-income adults with probable mental illness using the National Survey on Drug Use and Health with state identifiers. This study employed difference-in-difference models to compare ME states to non-expansion states before (2010-2013) and after (2014-2017) expansion and triple difference models to examine these changes across non-Hispanic White (NHW), non-Hispanic Black (NHB), and Hispanic/Latino racial/ethnic subgroups. Insurance coverage increased significantly for all racial/ethnic groups in expansion states relative to non-expansion states (DD: 9.69; 95% CI: 5.17, 14.21). The proportion low-income adults that received treatment but still had unmet need decreased (DD: -3.06; 95% CI: -5.92, -0.21) and the proportion with unmet need and no mental health treatment increased (DD: 2.38; 95% CI: 0.03, 4.73). ME was not associated with reduced disparities.

The Patient Protection and Affordable Care Act and oral health care use among formerly incarcerated people in the United States.

BACKGROUND: Formerly incarcerated people report less frequent oral health care use, despite having more substantial oral health problems. This study aimed to determine whether the adoption of the Patient Protection and Affordable Care Act (ACA) has improved oral health care use among formerly incarcerated people in the United States. METHOD: Data were from Wave I (1994-1995), Wave IV (2008), and Wave V (2016-2018) of the National Longitudinal Study of Adolescent to Adult Health (n = 9,108), a nationally representative cohort study in the United States. RESULTS: On the basis of the results of multiple logistic regression analysis with interaction terms, the authors found a positive and statistically significant interaction between prior incarceration and living in a state with ACA adoption on past-year oral health care use, net of potential confounding variables (incarceration × ACA: odds ratio, 1.587; 95% CI, 1.043 to 2.414). Substantively, the findings suggest that people with a history of incarceration are less likely to use oral health care, and this disparity is more likely to occur in states without ACA adoption. CONCLUSIONS: ACA adoption corresponds with improvements in the receipt of oral health care among formerly incarcerated people. PRACTICAL IMPLICATIONS: This study builds on prior evidence highlighting that the ACA is beneficial in connecting formerly incarcerated people to health care services and suggests that these benefits may extend to improving access to and use of oral health care.

The association between the Patient Protection and Affordable Care Act and healthcare affordability among US adults with intellectual disability.

BACKGROUND: Historically, US adults with intellectual disability (ID) experience worse healthcare access than the general population. However, the implementation of the Patient Protection and Affordable Care Act (ACA) may have reduced disparities in healthcare access. METHODS: Using a pre-ACA 2011-2013 sample and a post-ACA implementation 2014-2016 sample from the National Health Interview Survey data, we examined the association between the ACA's introduction and healthcare access among adults with ID (N = 623). Negative binomial regression models were used to test the association between the ACA and the total number of foregone healthcare services. Binary logistic regression was used to explore whether the ACA's implementation was associated with the increased likelihood of possessing health insurance as well as the decreased likelihood of any and particular measures of foregone healthcare services due to cost. RESULTS: The study provides evidence that the ACA's implementation was associated with the decreased likelihood of the total number and any foregone care services owing to cost. Findings also revealed that the ACA's implementation was associated with expansion of health insurance coverage and decreasing instances of foregone care services for medical care, dental care, specialist visit and mental care among adults with ID. However, persons with ID were still at a higher risk of foregone prescription medicines, follow-up medical care and eyeglasses due to cost in the post-ACA years. CONCLUSIONS: The study provides evidence that healthcare access among Americans with ID improved after the ACA's implementation. However, challenges in access to follow-up care, eyeglasses and prescription medicines persist and require policy solutions, which extend beyond the ACA's provisions.

Differences in Financial Conflicts of Interest Among Participants in a National Spine Conference.

STUDY: Retrospective Study. OBJECTIVE: At the North American Spine Society (NASS) conference, participants may influence spine surgery practices and patient care through their contributions. Therefore, their financial conflicts of interest are of notable interest. This study aims to compare the demographics and payments made to participating surgeons. METHODS: A list of 151 spine surgeons was created based on those who participated in the 2022 NASS conference. Demographic information was obtained from public physician profiles. General payments, research payments, associated research funding, and ownership interest were collected for each physician. Descriptive statistics and two-tailed t-tests were used. RESULTS: In 2021, 151 spine surgeon participants received industry payments, totaling USD 48 294 115. The top 10% of orthopedic surgeons receiving payments accounted for 58.7% of total orthopedic general value, while the top 10% of neurosurgeons accounted for 70.1%. There was no significant difference between these groups' general payment amounts. Surgeons with 21-30 years of experience received the most general funding. There was no difference in funding between surgeons in academic or private settings. For all surgeons, royalties accounted for the largest percentage of the general value exchanged, while food/beverage accounted for the largest percentage of transactions. CONCLUSIONS: Our study found that only years of experience had a positive association with general payments, and most monetary value belonged to a small handful of surgeons. These participants receiving significant money may promote techniques requiring products of companies providing their compensation. Future conferences may require disclosure policy changes so attendees understand the degree of funding participants receive.

Early changes in health coverage and access to dental care associated with Medicaid expansion under the COVID-19 pandemic.

The extent to which the COVID-19 pandemic has affected early changes in health coverage and access to dental care services in states that expanded Medicaid versus those that did not is currently not well known. Using data from the National Health Interview Survey, we found that, during the first year of the COVID-19 pandemic, states that had previously expanded their Medicaid programs under the Affordable Care Act had lower uninsurance rates for White low-income adults (-8.8 percentage points; 95% CI: -16.6, -1.0) and lower dental uninsurance rates for all low-income adults (-5.4 percentage points; 95% CI: -10.4, -0.5). Our findings also suggest that the combination of Medicaid expansion with coverage of adult dental benefits in Medicaid was associated with improved dental coverage and access to dental care during the pandemic. With the expiration of the public health emergency declaration, states are considering strategies to prevent disruptions in Medicaid coverage. Our study adds to the evidence of the importance of Medicaid expansion in stabilizing health coverage during a public health crisis.

And Then There Were Three: The Decimation of the Affordable Care Act (ACA) CO-OPs.

The Consumer Operated and Oriented Plans (CO-OPs), the subject of Section 1322 of the Affordable Care Act (ACA), were to constitute "qualified nonprofit health insurance issuers." Designed with an eye toward increasing competition with the extant commercial and nonprofit insurance sector, the CO-OPs were to enhance consumer choice as well as hold down prices on the state and federal exchanges. To achieve these ends, the consumer-governed state-licensed CO-OPs were to target the individual and small-group markets. At least one qualified CO-OP was to be established in each and every state. By the fall of 2013, however, coincident with the first open enrollment period of the ACA, only 23 CO-OPs were on tap. At the time of this writing, only three of these CO-OPs remain operational in the states of Maine, Montana, and Wisconsin. Viewed in hindsight, the thorough dissolution of the CO-OPs was the product of incremental financial privation effectuated by congressional opponents of the ACA. In this Commentary, we revisit the ontogeny of the CO-OP construct, review its partisan dismantling, and explore the potential resurrection thereof.

The impact of Medicaid funding structures on inequities in health care access for Latinos in New York, Florida, and Puerto Rico.

OBJECTIVE: To study the impact of Medicaid funding structures before and after the implementation of the Affordable Care Act (ACA) on health care access for Latinos in New York (Medicaid expansion), Florida (Medicaid non-expansion), and Puerto Rico (Medicaid block grant). DATA SOURCES: Pooled state-level data for New York, Florida, and Puerto Rico from the 2011-2019 Behavioral Risk Factor Surveillance System and data from the 2011-2019 American Community Survey and Puerto Rico Community Survey. STUDY DESIGN: Cross-sectional study using probit with predicted margins to separately compare four health care access measures among Latinos in New York, Florida, and Puerto Rico (having health insurance coverage, having a personal doctor, delayed care due to cost, and having a routine checkup). We also used difference-in-differences to measure the probability percent change of having any health insurance and any public health insurance before (2011-2013) and after (2014-2019) the ACA implementation among citizen Latinos in low-income households. DATA COLLECTION: The sample consisted of Latinos aged 18-64 residing in New York, Florida, and Puerto Rico from 2011 to 2019. PRINCIPAL FINDINGS: Latinos in Florida had the lowest probability of having health care access across all four measures and all time periods compared with those in New York and Puerto Rico. While Latinos in Puerto Rico had greater overall health care access compared with Latinos in both states, health care access in Puerto Rico did not change over time. Among citizen Latinos in low-income households, New York had the greatest post-ACA probability of having any health insurance and any public health insurance, with a growing disparity with Puerto Rico (9.7% any [1.6 SE], 5.2% public [1.8 SE]). CONCLUSIONS: Limited Medicaid eligibility (non-expansion of Florida's Medicaid program) and capped Medicaid funds (Puerto Rico's Medicaid block grant) contributed to reduced health care access over time, particularly for citizen Latinos in low-income households.

Effect of Medicaid Expansion on Visit Composition in a Louisiana Health Care System.

Background: In 2016, Louisiana expanded Medicaid to low-income adults under the Patient Protection and Affordable Care Act. By 2020, the uninsured rate of adults in Louisiana had dropped from 22.7% to 8.9%; however, few reports describe the effect Medicaid expansion has had on access and utilization of health care services in Louisiana. Methods: For this study, we collected all-payer emergency department and clinic visits from one health care system in Louisiana from 2015 to 2019. We used a time series analysis to compare trends before and after Medicaid expansion in health insurance coverage and emergency department visit type. Results: The changes in payer mix in the urgent care and primary care clinics and emergency departments after Medicaid expansion was driven by the uptake of Medicaid coverage in the previously uninsured. Medicaid expansion had a limited impact on the number of urgent care and emergent and nonemergent emergency department visits, but an increase in primary care visits was observed. Conclusion: Medicaid expansion reduced uncompensated care in our patient population and expanded the access to primary care clinics. Ongoing research is needed to understand the effect of nonfinancial barriers to care on access to and utilization of services in Louisiana.

Association of State Medicaid Expansion Status With Hypertensive Disorders of Pregnancy in a Singleton First Live Birth.

BACKGROUND: Incidence of hypertensive disorders of pregnancy is increasing in the United States. Early detection is important to prevent adverse maternal and offspring outcomes. This ecological study evaluated changes in rates of hypertensive disorders of pregnancy among states that expanded Medicaid compared with states that did not expand Medicaid. METHODS: A quasi-experimental analysis using difference-in-differences models compared changes in rates of hypertensive disorders of pregnancy in Medicaid expansion states relative to non-Medicaid expansion states from 2012 to 2019. Maternal data from singleton first live births to individuals aged 20 to 39 years were obtained from the National Center for Health Statistics. Outcomes of interest included age-adjusted rates of de novo hypertension in pregnancy (gestational hypertension or preeclampsia) and prepregnancy hypertension. RESULTS: Data from 7 764 965 individuals with a singleton first live birth were analyzed from 17 states and Washington, DC that expanded Medicaid and 15 states that did not. Rates of de novo hypertension in pregnancy increased over the study period in both expansion (54.34 [95% CI, 48.25-60.43] to 74.87 [95% CI, 71.20-78.55] per 1000 births) and nonexpansion states (68.32 [95% CI, 61.02-75.62] to 84.79 [95% CI, 80.67-88.91] per 1000 births). In adjusted difference-in-differences analyses, expansion status was associated with a greater increase in rates of de novo hypertension in pregnancy (difference-in-differences coefficient, +8.18 [95% CI, 4.00-12.36] per 1000 live births) but a decline in rates of de novo hypertension in pregnancy complicated by low birth weight (-7.20 [95% CI, -13.71 to -0.70] per 1000 births with hypertensive disorders of pregnancy). In adjusted difference-in-differences analyses, there were no significant changes in rates of prepregnancy hypertension in expansion relative to nonexpansion states (+1.13 [95% CI, -0.09 to +2.35] per 1000 live births). CONCLUSIONS: Between 2012 and 2019, states that expanded Medicaid had a significantly greater increase in rates of de novo hypertension, with some evidence of better outcomes among those with de novo hypertension diagnosed in pregnancy.

Medicaid expansion and postpartum depressive symptoms: evidence from the 2009-2018 Pregnancy Risk Assessment Monitoring System survey.

PURPOSE: This population-representative study examined the association of Medicaid expansion under the Patient Protection and Affordable Care Act (ACA) with postpartum depressive symptoms among low-income women. METHODS: We used data from the 2009 - 2018 Pregnancy Risk Assessment Monitoring System (PRAMS) surveys for 13 Medicaid expansion and 7 non-expansion states. We used a generalized difference-in-differences approach and log-binomial regression models to calculate prevalence ratios (PRs) and 95% confidence intervals (CIs) comparing the likelihood of postpartum depressive symptoms among low-income women (≤138% of the federal poverty level) who delivered in expansion and non-expansion states. RESULTS: Adjusting for state and year fixed-effects and individual- and state-level confounders, low-income women who delivered in Medicaid expansion states had a decreased likelihood of postpartum depressive symptoms compared to low-income women who delivered in non-expansion states (PR = 0.93, 95% CI 0.80, 1.07). Results were largely consistent across multiple sensitivity analysis specifications. Results were robust to falsification tests among women with incomes >138% of the federal poverty level. CONCLUSION: Our results indicate that Medicaid expansion may be associated with a small reduction in the likelihood of postpartum depressive symptoms. Future research should examine the potential for implementation of multiple supportive policies to achieve larger gains in treatment and prevention.

Accessibility of the Affordable Care Act (ACA) marketplace websites.

BACKGROUND: The Affordable Care Act (ACA) mandated that creation of online health insurance websites to ease the complex process of shopping for and enrolling into coverage. Ensuring that these sites are not only available but also meet digital accessibility standards is important so that individuals with disabilities are able to access healthcare services and efficiently obtain insurance coverage. METHOD: We evaluated each of the marketplace sites in 2020 to assess whether they are digitally accessible. We employed a custom audit tool based on a subset of the Web Content Accessibility Guidelines (WCAG) 1.0 and 2.0 AA and used content analysis to compare the site's accessibility statements with best practices. RESULTS: Nearly all of the ACA marketplace websites have significant room to improve their digital accessibility. Notable technical problem areas include lack of text equivalents for images, difficult site navigation, and lack of optimization for mobile use, particularly on those pages that provide instructions on how to get in-person help. CONCLUSIONS: Given that access to health insurance is a primary predictor of access to health care - sites must be easy to use and accessible to all individuals regardless of ability. Barriers to online enrollment, such as those identified in this work, may exacerbate disparities in quality of care, treatment continuity and affordability for individuals with mental and physical disabilities. Entities providing health-related online information & engagement should be aware of actionable opportunities to improve digital accessibility to optimize the enrollment process for both maintaining coverage and assisting those that remain uninsured.

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.

The impact of Medicaid expansion on emergency department wait times.

OBJECTIVE: To estimate the impact of Medicaid expansion on emergency department (ED) wait times. DATA SOURCES: We used 2012-2017 hospital-level secondary data from the CMS Hospital Compare data warehouse. STUDY DESIGN: We used a state-level difference-in-differences approach to identify the impact of Medicaid expansion on four measures of ED wait times: time before being seen by a provider; time before being sent home after being seen by a provider; boarding time spent in the ED waiting to be discharged to an inpatient room; and the percentage of patients who left without being seen. We compared outcomes in states that expanded Medicaid with those in states that did not expand Medicaid. DATA COLLECTION/EXTRACTION METHODS: Our sample included all US acute care hospitals with EDs in states that did not ever expand Medicaid or that fully expanded Medicaid in January of 2014. PRINCIPAL FINDINGS: Medicaid expansion was associated with a 3.1-min increase (SE: 0.994, baseline mean: 30.8 min) in the time spent waiting to see an ED provider, a relative increase of 10%. Patients who were eventually sent home after being seen by a provider experienced a 7.5-min increase (SE: 1.8, baseline mean 142.1 min) in wait time. Boarding time rose by 3.8 min (SE 1.9, baseline mean 111.4 min). The percentage of patients who left without being seen rose by 0.3 percentage points (SE: 0.09, baseline mean 2.0), a relative increase of 15.3%. CONCLUSIONS: This study provides multistate evidence that Medicaid expansion increased ED wait times for patients, indicating that ED crowding may have worsened post-expansion. Future work should aim to uncover the mechanisms through which insurance expansion increased ED wait times to provide policy direction.

Patient Perspective of People with HIV Who Gained Medicaid Through Medicaid Expansion: A Cross-Sectional Qualitative Study.

Given the large numbers of people with HIV (PWH) with Medicaid coverage, it is important to understand the patient experience with Medicaid. Understanding experiences with and attitudes around the program have important policy and clinical implications. The objective was to understand the patient perspective of PWH in Virginia, who transitioned to Medicaid in 2019 due to Medicaid expansion. English-speaking PWH who gained Medicaid due to Medicaid expansion in 2019 were recruited at one Virginia Ryan White HIV/AIDS Program clinic. The goal was to enroll >33% of those who newly were on Medicaid for 2019. Participants were surveyed about demographic characteristics, and semistructured interviews were performed. Descriptive analyses were performed for cohort characteristics. Using qualitative description and an open coding strategy, codebooks were generated for the interviews and themes were identified. The cohort (n = 28) met our recruitment goal. Most participants had positive feelings about Medicaid before enrollment (general: 68%; good for general health: 75%, and good for HIV care: 67%) and after enrollment (general: 93% and good for HIV care: 93%). All participants expressed incomplete understanding about Medicaid before enrollment. Seventy-nine percent needed outside help to complete enrollment. Approximately 40% described overlaps of Medicaid with other insurance/payers or gaps in insurance coverage when transitioning from one insurance/payer (such as AIDS Drug Assistance Program [ADAP] medication provision and ADAP-subsidized insurance) to Medicaid. Participants suggested more access or easier access to information about Medicaid and more explanation of Medicaid benefits would be helpful. Our findings indicate participants had mostly positive perceptions of Medicaid before and after enrollment. Even with enrollment help, participants voiced that dealing with insurance is hard. Medicaid and other programs should prioritize more access to information, smoother processes, and less burdensome enrollment/re-enrollment.

Association of Medicaid expansion under the Affordable Care Act with access to elective spine surgical care.

OBJECTIVE: The Affordable Care Act expanded Medicaid eligibility in many states, improving access to some forms of elective healthcare in the United States. Whether this effort increased access to elective spine surgical care is unknown. This study's objective was to evaluate the impact of Medicaid expansion under the Affordable Care Act on the volume and payer mix of elective spine surgery in the United States. METHODS: This study evaluated elective spine surgical procedures performed from 2011 to 2016 and included in the all-payer State Inpatient Databases of 10 states that expanded Medicaid access in 2014, as well as 4 states that did not expand Medicaid access. Adult patients aged 18-64 years who underwent elective spine surgery were included. The authors used a quasi-experimental difference-in-difference design to evaluate the impact of Medicaid expansion on hospital procedure volume and payer mix, independent of time-dependent trends. Subgroup analysis was conducted that stratified results according to cervical fusion, thoracolumbar fusion, and noninstrumented surgery. RESULTS: The authors identified 218,648 surgical procedures performed in 10 Medicaid expansion states and 118,693 procedures performed in 4 nonexpansion states. Medicaid expansion was associated with a 17% (95% CI 2%-35%, p = 0.03) increase in mean hospital spine surgical volume and a 23% (95% CI -0.3% to 52%, p = 0.054) increase in Medicaid volume. Privately insured surgical volumes did not change significantly (incidence rate ratio 1.13, 95% CI -5% to 34%, p = 0.18). The increase in Medicaid volume led to a shift in payer mix, with the proportion of Medicaid patients increasing by 6.0 percentage points (95% CI 4.1-7.0, p < 0.001) and the proportion of private payers decreasing by 6.7 percentage points (95% CI 4.5-8.8, p < 0.001). Although the magnitude of effects varied, these trends were similar across procedure subgroups. CONCLUSIONS: Medicaid expansion under the Affordable Care Act was associated with an economically and statistically significant increase in spine surgery volume and the proportion of surgical patients with Medicaid insurance, indicating improved access to care.