Primary care workforce structural inertia and Medicaid participation during the COVID-19 pandemic, 2020-2021.

Introduction: Ensuring adequate participation of the primary care workforce in Medicaid is a persistent challenge for policymakers, yet the underlying clinician behaviors that sustain Medicaid patient access remain poorly understood. Methods: We examined linked Medicaid and commercial insurance claims volume data from 11 states between 2020 and 2021 to determine how patient volumes were distributed among the workforce during the COVID-19 pandemic. Results: We found that access to care was sustained by a dedicated core of anchor clinicians, representing 18% of the workforce, who consistently managed high patient volumes in every quarter. In contrast, about 33% of clinicians did not participate in the Medicaid program throughout the study period. Conclusion: These findings reveal that Medicaid participation reflects enduring practice patterns: clinicians tend to either consistently treat these patients or avoid the program altogether, rather than frequently changing their availability. To protect Medicaid patients' access against future economic or policy disruptions, state policymakers must move beyond simple clinician headcounts. We recommend designing targeted interventions to explicitly support and retain the critical anchor clinicians provide most of the care.