Association Between the ACA Medicaid Expansions and Changes in Cardiovascular Risk Factors Among Low-Income Individuals

Abstract

Background: Evidence is limited as to whether the introduction of the Affordable Care Act (ACA)'s Medicaid expansions was associated with improvements in cardiovascular risk factors at the population level.

Objective: To examine the association between the ACA Medicaid expansions and changes in cardiovascular risk factors among low-income individuals during the first 3 years of the implementation of the ACA Medicaid expansions at the national level.

Design: A quasi-experimental difference-in-differences (DID) analysis to compare outcomes before (2005-2012) and after (2015-2016) the implementation of the ACA Medicaid expansions between individuals in states that expanded Medicaid and individuals in non-expansion states.

Participants: A nationally representative sample of individuals aged 19-64 years with family incomes below 138% of the federal poverty level from the 2005-2016 National Health and Nutrition Examination Survey (NHANES).

Intervention: ACA Medicaid expansions.

Main measures: Cardiovascular risk factors included (1) systolic and diastolic blood pressure, (2) hemoglobin A1c (HbA1c) level, and (3) cholesterol levels (low-density lipoprotein cholesterol, triglyceride, and high-density lipoprotein cholesterol).

Key results: A total of 9177 low-income individuals were included in our analysis. We found that the ACA Medicaid expansions were associated with a lower systolic blood pressure (DID estimate, - 3.03 mmHg; 95% CI, - 5.33 mmHg to - 0.73 mmHg; P = 0.01; P = 0.03 after adjustment for multiple comparisons) and lower HbA1c level (DID estimate, - 0.14 percentage points [pp]; 95% CI, - 0.24 pp to - 0.03 pp; P = 0.01; P = 0.03 after adjustment for multiple comparisons). We found no evidence that diastolic blood pressure and cholesterol levels changed following the ACA Medicaid expansions.

Conclusion: Using the nationally representative data of individuals who were affected by the ACA, we found that the ACA Medicaid expansions were associated with a modest improvement in cardiovascular risk factors related to hypertension and diabetes during the first 3 years of implementation.

Keywords: ACA Medicaid expansions; diabetes; health policy; hyperlipidemia; hypertension.