Cost-sharing With Medicaid Expansion in Michigan: Obligations and Propensity to Pay.

Background: Six states expanding Medicaid under the Affordable Care Act have obtained waivers to incorporate cost-sharing.

Objective: We describe the magnitude and distribution of cost-sharing imposed by the Healthy Michigan Plan and enrollees' propensity to pay.

Research Design: Enrollees are followed for at least 18 months (6-mo baseline period for utilization and spending before receipt of first cost-sharing statement; ≥12 mo follow-up thereafter to ascertain obligations and payments). Analyses stratified by income, comparing enrollees with income less than Federal Poverty Level (FPL) who faced only utilization-based copayments and those greater than or equal to FPL who also faced premium contributions.

Subjects: A total of 158,322 enrollees aged 22-62 who initially enrolled during the first year of the program and remained continuously enrolled ≥18 months.

Results: Among those enrolled ≥18 months, 51.0% faced cost-sharing. Average quarterly invoices were $4.85 ($11.11 for those with positive invoices) for income less than FPL and $26.71 ($30.93 for those with positive invoices) for incomes greater than or equal to FPL. About half of enrollees with obligations made at least partial payments, with payments being more likely among those >100% FPL. Payment of the full obligation was highest in the initial 6 months.

Conclusions: Many payment obligations go uncollected, suggesting that in a system without the threat of disenrollment, the impacts of cost-sharing may be muted. Similarly, the ability of cost-sharing to defray the program's budgetary impact may also be less than anticipated.