Longer Run Effects of Medicaid Expansion on Racial/Ethnic Disparities in Intermediate Health Outcomes Among a National Sample of FQHCs
Authors: Cole Megan 
Published: September 2021

Research Objective

Prior to implementation of Medicaid expansion under the Affordable Care Act, 40% of federally qualified health center (FQHC) patients across the US were uninsured, 92% had incomes below 200% of the federal poverty level, and 65% were from racial/ethnic minority groups. While recent evidence has found that Medicaid expansion was associated with short‐term gains in insurance coverage and receipt of recommended services at FQHCs, there is limited evidence about the longer‐term impacts of expansion on health outcomes, and no known evidence about longer‐term impacts on racial/ethnic disparities in health outcomes. Thus, our objective was to assess the six‐year impact of Medicaid expansion on racial/ethnic disparities in intermediate health outcomes using nationally representative data on all FQHCs.

Study Design

Using the 2011–2019 Uniform Data System, we measured three available intermediate clinical quality measures that may be sensitive to Medicaid expansion: (1) percent of adult diabetic patients with a hemoglobin A1c level of less than 9%; (2) percent of adult hypertensive patients whose blood pressure was less than 140/90 mmHg; and (3) percentage of live births among FQHC prenatal care patients with normal birth weight (> = 2500 grams). The clinical quality measures were assessed for the full population and separately for each racial/ethnic group.

We conducted staggered difference‐in‐differences (DID) analyses to compare outcomes in FQHCs located in expansion versus non‐expansion states. For each measure, a difference‐in‐difference was calculated using a linear probability model. All models included an indicator for whether the FQHC was ever in the expansion treatment group; an indicator for whether the FQHC was in a state that was actively implementing Medicaid expansion as of year y (the parameter of interest); a vector of time‐variant covariates; state and year fixed effects; and clustered errors at the FQHC‐level.

Population Studied

100% sample of all FQHCs in the US (N = 1042 after exclusions), representing over 20 million patients per year.

Principal Findings

In states that expanded Medicaid, the percent of FQHC patients without insurance declined substantially subsequent to expansion, with the largest declines occurring during the initial expansion year. The impact of expansion on outcomes took 2–3 years post‐expansion to be detected, where by year six, expansion was associated with the greatest magnitude of change in (1) blood pressure control among Black patients (difference‐in‐difference by year 6: 3.32 PP, 95% CI 0.64–5.99) and Hispanic patients (difference‐in‐difference by year 6: 2.44 PP, 95% CI 0.09–4.78) and (2) diabetes control among Hispanic patients (difference‐in‐difference in year 6: 3.53 PP, 95% CI 1.02–6.04). Racial/ethnic disparities decreased for White vs. Black hypertension control only. No statistically significant effect on birth weight was observed, although this appeared to be due to fewer pregnant women receiving prenatal care at FQHCs post‐expansion.

Conclusions

The first six years of Medicaid expansion were associated with increases in insurance coverage and improvement in two of three measured intermediate health outcomes among FQHC patients, especially for Black and Hispanic patients, but these changes took 2–3 years to be detected.

Implications for Policy or Practice

Findings highlight the longer‐term, significant role of Medicaid expansion in improving health outcomes. Efforts to limit eligibility may compromise this progress.

Primary Funding Source

Agency for Healthcare Research and Quality.