Purpose: To understand primary care provider participation in Medicaid programs across states and provider specialties and professions.
Methods: We examined the 2016 Medicaid claims data across 45 states and territories from the Transformed Medicaid Statistical Information System (T-MSIS).
Results: Of the 616,182 primary care providers we identified, 111,152 (18.0%) saw no Medicaid patients, 88,723 (14.4%) providers saw one to 10 Medicaid patients, 163,806 (26.6%) saw 11 to 100 Medicaid patients, and 252,501 (41.0%) saw more than 100 Medicaid patients in 2016. The proportion of providers who saw more than 100 Medicaid patients ranged from 22.9% in Virginia to 56.1% in New Mexico. Medicaid participation also differed by specialty, from 78.4% among pediatricians to 61.2% among nurse practitioners. This study lays the foundations for using T-MSIS data to identify communities at the highest risk for access barriers and support targeted policy responses.