Medicaid and CHIP Premiums and Access to Care: A Systematic Review.

Abstract

Premiums are required in Medicaid and the Children's Health Insurance Program in many states. Effects of premiums are raised in policy debates. Our objective was to review effects of premiums on children's coverage and access. PubMed was used to search academic literature from 1995 to 2014. Two reviewers initially screened studies by using abstracts and titles, and 1 additional reviewer screened proposed studies. Included studies focused on publicly insured children, evaluated premium changes in at least 1 state/local program, and used longitudinal or repeated cross-sectional data with pre/postchange measures. We identified 263 studies of which 17 met inclusion criteria. Four studies examined population-level coverage effects by using national survey data, 11 studies examined trends in disenrollment and reenrollment by using administrative data, and 2 studies measured additional outcomes. No eligible studies evaluated health status effects. Increases in premiums were associated with increased disenrollment rates in 7 studies that permitted comparison. Larger premium increases and stringent enforcement tended to have larger effects on disenrollment. At a population level, premiums reduce public insurance enrollment and may increase the uninsured rate for lower-income children. Little is known about effects of premiums on spending or access to care, but 1 study reveals premiums are unlikely to yield substantial revenue. Effect sizes were difficult to compare across studies with administrative data. Public insurance premiums often increase disenrollment from public insurance and may have unintended consequences on overall coverage for low-income children.