In measuring the effects of health insurance coverage expansion as part of our ACAView initiative with Robert Wood Johnson Foundation (RWJF), an important factor to consider is state policy towards Medicaid expansion.
The intention of the Affordable Care Act (ACA) was to expand coverage through two mechanisms: 1) People with moderate incomes could gain coverage through the exchanges, often encouraged by subsidies; and 2) those with lower incomes could gain coverage through an expansion of Medicaid eligibility to include groups that had not traditionally qualified for Medicaid.
For many years, states had widely varying Medicaid eligibility rules, with some states covering only women and their children in need of public aid and low-income people with disabilities. Other states had expanded eligibility to include people at income levels higher than the federal poverty level.
Given the differing Medicaid expansion decisions among states, we examined our data on visits to primary care physicians (PCPs) separately for states with and without Medicaid expansion.
Figure 1 shows proportions of visits between January 2012 and May 2014 for four groups of adults (18-64): uninsured individuals in Medicaid-expansion states; uninsured individuals in non-Medicaid expansion states; Medicaid beneficiaries in expansion states; and Medicaid beneficiaries in non-expansion states.
Two observations are worth noting:
- ACA coverage expansion appears to be widening a pre-existing gap between states that have elected to pursue Medicaid expansion and those that have not. Providers in the Medicaid-expansion states were already seeing higher proportions of Medicaid beneficiaries in 2013. For example, in December of 2013, 12.3% of 18-64 year- old visits to PCPs in expansion states were from Medicaid beneficiaries, compared with 5.9% in non-expansions states, a 6.4 percentage point differential. By May 2013, that difference had expanded to a 9.3 percentage point differential, as the percent of Medicaid visits increased in Medicaid expansion states but held constant in non-expansion states.
- The proportion of uninsured fell in both categories, from 4.5% to 3.3% in expansion states and 7.0% to 5.8% in non-expansion states (figures for January through May for both years, respectively).
Figure 2 expands the Medicaid payer mix analysis to other specialties.
In Medicaid expansion states, all four specialty types showed a substantial increase in the proportion of visits by Medicaid beneficiaries. In contrast, in non-Medicaid expansion states, the proportion of visits by Medicaid beneficiaries decreased for all four specialty groups.
As a result of these changes, by early 2014 PCPs, surgeons, and other specialists in expansion states saw two to three times more adult Medicaid patients (in proportional terms) than in non-expansion states (for example, 15.6% versus 6.3% for PCPs; 11.6% versus 3.1% for surgeons).
For OB-GYN, the ratio between the proportion of visits by Medicaid beneficiaries in the expansion and non-expansion states is much smaller, 19.4% versus 13.4%. This may reflect more generous Medicaid eligibility in non-expansion states for pregnant women compared to other adults.
As we monitor these metrics, a few questions will be of particular interest:
- Where will the increase in Medicaid volumes in expansion states level off?
- To what extent is the increase in Medicaid visits driven by established patients who were previously uninsured?
- What are the effects of increased Medicaid volumes on medical practices?
We will attempt to address these (and other) complex issues throughout the year.
For a better understanding of our goals, methodology, data sample size, and full findings since the inception of the ACAView series, please read our first report, “First Observations Around the Affordable Care Act.”