Enrollment differences between Medicaid and CSR plans

Bhanja et al have a new JAMA Health Forums article that asks a very important question:

For people who barely qualify for Medicaid Expansion instead of ACA CSR (Cost-Sharing Reduction) plans, are there differences in enrollment rates?

The short answer is YES!!!!

In this cross-sectional study with a regression discontinuity analysis of 87 542 US adult enrollees in Medicaid and private insurance, marketplace enrollment was 81.3% lower than Medicaid enrollment in 2014 and 88.6% lower in 2015 among those close to the eligibility threshold. The drop-off in marketplace enrollment was largest among younger adults.

These are huge differences (80%+) where a few hundred dollars of additional income can dramatically change the probability of being insured.

Younger individuals were more likely to not be enrolled in ACA plans if they were just above the income threshold.

Individuals with significant pre-existing conditions were slightly more likely to be enrolled in ACA if they were above the income threshold.

But no matter how the data is sliced, the drop-off in coverage for people who are just eligible for Medicaid Expansion to people who are just eligible for only CSR ACA plans is massive.

So what is going on here?

There could be a couple of different things. Medicaid does not have premiums. ACA Silver plans have premiums of 2% to 4% of income for the group in question. Medicaid has little to no cost-sharing while even a CSR-94 Silver plan has significant cost-sharing for someone earning under 150% FPL. This same research team had found significant cost-sharing differences between folks who were just Medicaid eligible and just ACA eligible during the same time period from a January 2021 manuscript. The ACA plans were new during this research study so there was also a lot of learning by doing on finding a new pathway into a new system.

It seems like, at least early on, that there were a massive number of barriers to access and enrollment for individuals who were just barely eligible for ACA plans. Improvements in the consumer shopping experience and the proliferation of zero premium plans through ARA enhanced subsidies likely has removed some of these barriers but they are likely to remain as the entire process is predicated on constant choice and multiple points where an individual who wants health insurance can screw up. Expanding Medicaid eligibility further up the income scale is a possible improvement path by lowering barriers to enrollment, decreasing consumer cost-sharing and likely decreasing federal spending. Individuals and the federal government would be likely winners, while state general funds would be a loser if there is not a waiver to pass-through ACA funds to further Medicaid expansion, and clinicians would also likely see a reduction in income.