National and Regional Variation in Local Primary Care Physician Density Relative to the Uninsured and the Affordable Care Act

This study is the first to examine primary care physician (PCP) density relative to the uninsured at the local level prior to and after insurance expansion under the Affordable Care Act. Primary care physician density is associated with access to care, lower inpatient and emergency care, and primary care services. However, access to primary care among the uninsured may be limited due to inadequate availability of PCPs. Core-Based Statistical Area (CBSA) data from the Area Health Resource File were retrospectively examined before and after Medicaid expansion. Multiple logistic regressions were modeled for PCP density with predictor interaction effects for percentage uninsured, Medicaid expansion status, and US Census regions. Medicaid expansion CBSAs had significantly lower proportions of uninsured and higher PCP density compared with their nonexpansion counterparts. Nationally, increasing proportions of the uninsured were significantly associated with decreasing PCP density. Most notably, there is an expected 32% lower PCP density in Western Medicaid expansion areas with many uninsured (90th percentile) compared with those with few uninsured (10th percentile). Areas expanding Medicaid with greater proportions of people becoming insured postexpansion had significantly fewer PCPs. Areas with greater proportions of the uninsured may have reduced access to primary care due to the paucity of PCPs in these areas. Efforts to improve access should consider a lack of local PCPs as a limitation for ensuring accessible and timely care. Health care and policy leaders should focus on answers to improve the local availability of primary care clinicians in underserved communities.