RESUMO
BACKGROUND: Many physicians listed as primary care in databases such as the American Medical Association (AMA) Masterfile do not provide traditional ambulatory primary care. OBJECTIVE: To compare physicians listed in the AMA Masterfile as primary care physician (PCPs) specialists for adult patients with their actual practice type. METHODS: We conducted a cross-sectional study of the AMA Masterfile report for PCPs who care for adults (listed as family medicine, internal medicine, medicine-paediatrics, and geriatrics) in the summer and fall of 2018 (spring of 2019 for Hartford, CT) in the primary counties of 8 metropolitan areas across the United States. We searched multiple websites to determine the actual practice type of each physician in the study counties. We correlated the 2 datasets: the AMA Masterfile list vs the results of our searches. RESULTS: Family physicians were more likely to function as traditional ambulatory PCPs than internists [1,738/2,101 (82.7%) vs 1,241/2,025 (60.9%), P < 0.001], and less likely to be hospitalists [83/2,101 (4.0%) vs 631/2,025 (31.0%), P < 0.001]. Other practice types included urgent care [105 (5.0%) family physicians, 16 (0.8%) internists] and emergency medicine [49 (2.3%) family physicians, 20 (1.0%) internists]. The AMA Masterfile identified 4,892 practicing PCPs for adult patients in the study counties, of which 3,084 (63.0%) matched by location and ambulatory PCP practice type [3,695 (75.5%) for ambulatory PCP practice type only]. CONCLUSIONS: We provide an updated estimate using a unique methodology to estimate how to correct the AMA Masterfile for PCPs who actually provide traditional ambulatory primary care to adult patients.