A comparison of two approaches to increasing access to care: expanding coverage versus increasing physician fees

Abstract

Objective: To compare the effects of a coverage expansion versus a Medicaid physician fee increase on children's utilization of physician services. PRIMARY DATA SOURCE: National Health Interview Survey (1997-2009).

Study design: We use the Children's Health Insurance Program, enacted in 1997, as a natural experiment, and we performed a panel data regression analysis using the state-year as the unit of observation. Outcomes include physician visits per child per year and the following indicators of access to primary care: whether the child saw a physician, pediatrician, or visited an ER in the last year, and whether the parents reported experiencing a non-cost-related access problem. We analyzed these outcomes among all children, and separately among socioeconomic status (SES) quartiles defined based on family income and parents' education.

Principal findings: Children's Health Insurance Program had a major impact on the extent and nature of children's insurance coverage. However, it is not associated with any change in the aggregate quantity of physician services, and its associations with indicators of access are mixed. Increases in physician fees are associated with broad-based improvements in indicators of access.

Conclusions: The findings suggest that (1) coverage expansions, even if they substantially reduce patient cost sharing, do not necessarily increase physician utilization, and (2) increasing the generosity of provider payments in public programs can improve access among low-SES children, and, through spillover effects, increase higher-SES children as well.

Figure 1

Estimated Effects on Insurance Coverage of a Large versus Small Children's Health Insurance Program (CHIP) Expansion (all children and separately by socioeconomic status quartile)Notes. The bar heights represent the estimated effects of CHIP enrollment under a large versus small expansion (i.e., a difference in enrollment of 4.7 percentage points) estimated using reduced form models. Children are assigned to a socioeconomic status quartile on the basis of their family income and parents' educational status (see Appendix SA1 for details). The drop bars indicate ±1 standard error. The results represent enrollment differences in percentage points. *p < .10, **p < .05, ***p < .01

Figure 2

Estimated Effects on Utilization of a Large versus Small Children's Health Insurance Program (CHIP) Expansion (all children, and separately by socioeconomic status quartile)Notes. The bar heights represent the estimated effects of CHIP enrollment under a large versus small expansion (i.e., a difference in enrollment of 4.7 percentage points) estimated using reduced form models. Children are assigned to a socioeconomic status quartile on the basis of their family income and parents' educational status (see Appendix SA1 for details). The drop bars indicate ±1 standard error. The results represent enrollment differences in percentage points. *p < .10, **p < .05, ***p < .01

Figure 3

Estimated Effects on Utilization of an Increase versus Decrease in the Medicaid Physician Primary Care Fee Index (all children, and separately by socioeconomic status quartile)Notes. The bar heights represent the estimated effects of a large increase (plus 15 percent) versus a large decrease (minus 15 percent) in the Medicaid physician fee index for primary care services (i.e., a difference of 30 percentage points) estimated using reduced form models. Children are assigned to a socioeconomic status quartile on the basis of their family income and parents' educational status (see Appendix SA1 for details). The drop bars indicate ±1 standard error. The results represent enrollment differences in percentage points. *p < .10, **p < .05, ***p < .01