Growth trends of the adult hospitalist workforce between 2012 and 2019.

Background: Accurately identifying the number of practicing hospitalists across the United States continues to be a challenge. Characterizing the workforce is important in the context of healthcare reforms and public reporting.

Objective: We sought to estimate the number of adult hospitalists practicing in the United States over an 8-year period, to examine patterns in growth, and begin to explore billing patterns.

Design, Settings, And Participants: Retrospective study using national Medicare Part B claims datasets. We applied a commonly used 90% threshold of billing hospital visit-associated Healthcare Common Procedure Coding System codes to identify adult hospitalists in publicly available Medicare Provider Utilization and Payment data for 2012-2019. We then analyzed billing patterns for those identified hospitalists.

Main Outcomes And Measures: Identify trends in the number of identified adult hospitalists, including those self-identified. Compare hospitalists' billing to that of non-hospitalist Internal Medicine and Family Medicine physicians.

Results: We saw more than a 50% growth rate of practicing adult hospitalists between 2012 and 2019. In 2019, we identified 44,037 adult hospitalists.

Conclusions: The number of adult hospitalists continued to grow at a consistent rate, such that hospitalists are in the top five largest physician specialties in the United States. In the absence of more formal identification and consistent use by hospitalists, a threshold continues to be a meaningful tool to characterize the workforce.