The Effect of Health Insurance Coverage on Medical Care Utilization and Health Outcomes: Evidence from Medicaid Adult Vision Benefits

Lipton, Brandy J; Lipton, Brandy J

Increasing the proportion of adults that have regular, comprehensive eye exams and reducing visual impairment due to uncorrected refractive error and other common eye health problems are federal health objectives. Many eye health problems are preventable and treatable, but also unlikely to exhibit apparent symptoms at an early stage, underscoring the potential benefit of preventive screening. Though low income individuals are least likely to visit an eye doctor regularly, Medicaid vision coverage is optional. While most states cover emergency eye care and treatment of medical eye problems, some states do not provide preventive eye care services such as routine exams and eyeglasses for correction of refractive error to adult Medicaid beneficiaries. For example, 28 states provided coverage of eyeglasses for correction of refractive error to adult Medicaid beneficiaries in FY 2013.

Providing a Medicaid adult vision benefit may encourage use of eye care services by reducing the out-of-pocket cost paid by the beneficiary. We examined the effect of insurance coverage of vision care on eye care utilization and vision health outcomes using 2002-2013 data from the National Health Interview Survey (NHIS). State coverage policies during this period were collected through internet search and contact with state health departments. Our main analysis involved a difference-in-difference-in-difference approach, which used variation in the timing of changes in vision coverage policy and a within-state control group of low income adults not enrolled in Medicaid to identify the effect of vision coverage policies on outcomes.

This study adds to the relatively sparse literature on the effects of Medicaid coverage among adults. Furthermore, according to preliminary estimates from the Centers for Medicare and Medicaid Services, enrollment in Medicaid and the Children’s Health Insurance Program increased by 7.5 million individuals between September 2013 and August 2014 in the 27 states that expanded their Medicaid programs to cover more low income adults. Some states that have opted to expand their Medicaid programs also offer adult vision benefits to the expansion population. Therefore, understanding the effect of vision coverage on use of eye care among the Medicaid population is of interest.

Our findings imply that vision coverage is associated with a more than four percentage point increase (p<0.01) in the likelihood of a yearly eye care visit, a reduction of about five percentage points (p<0.05) in the likelihood of needing but not purchasing vision correction in the past year due to cost, and a reduction of about two percentage points (p<0.05) in the likelihood of difficulty seeing with usual vision correction. These estimated effects represent changes of 16, 29, and 10 percent relative to their respective means for Medicaid beneficiaries without vision benefits.

Association for Public Policy Analysis & Management

Poster Paper: The Effect of Health Insurance Coverage on Medical Care Utilization and Health Outcomes: Evidence from Medicaid Adult Vision Benefits