Trends in hospital-physician integration in medical oncology.

Objectives: Hospitals have rapidly acquired medical oncology practices in recent years. Experts disagree as to whether these trends are related to oncology-specific market factors or reflect a general trend of hospital-physician integration. The objective of this study was to compare the prevalence, geographic variation, and trends in physicians billing from hospital outpatient departments in medical oncology with other specialties.

Study Design: Retrospective analysis of Medicare claims data for 2012 and 2013.

Methods: We calculated the proportion of physicians and practitioners in the 15 highest-volume specialties who billed the majority of evaluation and management visits from hospital outpatient departments in each year, nationally and by state.

Results: We included 338,998 and 352,321 providers in 2012 and 2013, respectively, of whom 9715 and 9969 were medical oncologists. Among the 15 specialties examined, medical oncology had the highest proportion of hospital outpatient department billing in 2012 and 2013 (35.0% and 38.3%, respectively). Medical oncology also experienced the greatest absolute change (3.3%) between the years, followed by thoracic surgery (2.4%) and cardiology (2.0%). There was marked state-level variation, with the proportion of medical oncologists based in hospital outpatient departments ranging from 0% in Nevada to 100% in Idaho.

Conclusions: Hospital-physician integration has been more pronounced in medical oncology than in other high-volume specialties and is increasing at a faster rate. Policy makers should take these findings into consideration, particularly with respect to recent proposals that may continue to fuel these trends.