Trends in the Concentration of Interventional Radiology Work among Radiologists in the United States: Analysis of...

To characterize longitudinal trends in the distribution of interventional radiology (IR) work across radiologists to determine whether work is concentrating among a smaller radiologist subset.

A retrospective, repeated cross-sectional analysis (2008-2023) of Medicare claims from a 5% sample of fee-for-service beneficiaries was used to identify radiology services. Radiologists were identified using Medicare Data on Provider Practice and Specialty data, and workload was classified as IR-related or non-IR-related using validated methodology. Radiologists were categorized by the proportion of IR-related work each year. Multivariable logistic regression evaluated associations between IR-workload concentration and radiologist and practice characteristics and year.

A total of 476,688 radiologist-years representing 46,533 unique radiologists were included. Radiologists who were male, aged 35-44 years, and in practices that are metropolitan and multispecialty and with 1-9 radiologists were the most likely to perform a majority IR work (>50%). The proportion of radiologists performing some (>0%) IR-related work declined from 66.9% in 2008 to 49.6% in 2023. Among those with IR-related work, the proportion with majority (>50%-100%) IR-related work increased from 12.6% to 18.5%, and the proportion with supermajority workloads (>90%-100%) increased from 4.1% to 8.8%. These trends were consistent across various radiologist and practice characteristics. For the 2020-2023 period, radiologists had higher odds of supermajority IR workloads than those for the 2008-2011 period (odds ratio, 1.65; 95% confidence interval, 1.10-2.46).

IR work has become increasingly concentrated among a smaller subset of radiologists indicating that a growing number of interventional radiologists are practicing primarily in their specialty as practice models evolve.