Low- and high-primary care physician states also vary by state Medicaid program characteristics. Medicaid reimbursement rates for primary care—as a percentage of Medicare rates—are much higher on average in low-primary care physician states (81.6%) compared to high-primary care physician states (54.8%) Low-primary care physician states also tend to have more restrictive Medicaid eligibility, as exemplified by the fact that only one—Arizona—currently allows Medicaid eligibility for at least some parents or childless adults with incomes above 100% of poverty, the study noted.
Accounting for differences in physician practice, patient and healthcare market characteristics, the study found that higher Medicaid reimbursement rates are associated with a greater probability of primary care physicians accepting all or most new Medicaid patients, although the effects are relatively modest. For primary care physicians, a 10% increase in the Medicaid/Medicare fee ratio for primary care was associated with only a 2.1% increase in primary care physicians Medicaid patient acceptance. Excluding pediatricians, the effects of reimbursement on Medicaid acceptance is slightly higher.
In other words, if primary care physicians in low-supply states were similar to primary care physicians in high-supply states on all measured factors other than level of reimbursement, Medicaid acceptance would be 5.7% higher in low-primary care physician states compared to high-primary care physician states, the study said.
One limitation of the study is that it treats the temporary Medicaid reimbursement increase as permanent, so estimates of the impact of the increases on primary care physicians' willingness to accept new Medicaid patients are likely overstated.
Based on information from HSC's nationally representative 2008 Health Tracking Physician Survey, the study's findings are detailed in a new HSC Research Brief—State Variation in Primary Care Physician Supply: Implications for Health Reform Medicaid Expansions—available online at www.hschange.org.