How Do Health Care Providers Respond to Public Health Insurance Expansions?

Dentists increase the supply of visits they provide and their practices serve a greater number of Medicaid-covered patients.

Medicaid is a government health insurance program that has historically enrolled children, pregnant women, and people with serious medical problems from low-income households. Private providers' services are paid for by state and federal governments. Individual states have the option to enroll able-bodied adults at various income levels, and have some flexibility in choosing the benefits available to them.

Between 1999 and 2011, three U.S. states added adult dental coverage to their Medicaid programs, six states dropped it, and three states did both. In How Do Providers Respond to Public Health Insurance Expansions? Evidence from Adult Medicaid Dental Benefits (NBER Working Paper No. 20053), Thomas C. Buchmueller, Sarah Miller, and Marko Vujicic explore state changes in Medicaid dental coverage to examine how dental practices responded to coverage expansions. They find that when publicly-provided dental insurance expands, dentists increase the supply of visits they provide and their practices serve a greater number of Medicaid-covered patients. The dentists increased their own working time by about a half-hour a week, and increased the supply of patient visits provided by employing more dental hygienists. Waiting times for appointments increased by almost a day in states in which dental hygienists were not allowed to bill Medicaid directly; they did not increase in states in which hygienists could bill directly.

Of the dental practices studied, 39 percent saw publicly insured patients. Visits by publicly-insured patients increased by about three per week, an increase of about nine percent; there was no significant change in visits by privately insured patients. Emergency or walk-in visits went up by about 0.5 visits per week, also an increase of 9 percent. About 67 percent of practices employed hygienists, and visits to them increased by 9 to 12 percent, about 4.5 to 6.1 visits per week. In high-poverty counties, the increase in walk-in visits was 5 times larger and the increase in use of dental hygienists was 2.5 times higher. Even after adjusting for the fact that hygienists may see patients from more than one dentist, the authors conclude that "making greater use of hygienists is an important part of how dentists meet the new demand created by the Medicaid policy changes."

-- Linda Gorman