Comparison of General Surgical Practice Size and Setting in 2017 vs 2013 in the US

IMPORTANCE: As health care delivery markets have changed and new payment models have emerged, physicians in many specialties have consolidated their practices, but whether this consolidation has occurred in surgical practices is unknown. OBJECTIVE: To examine changes in the size of surgical practices, market-level factors associated with this consolidation, and how place of service for surgical care delivery varies by practice size. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional study of Medicare Data on Provider Practice and Specialty from January 1 to December 31, 2013, compared with January 1 to December 31, 2017, was conducted on all general surgeon practices caring for patients enrolled in Medicare in the US. Data analysis was performed from November 4, 2019, to January 9, 2020. EXPOSURES: Practice sizes in 2013 and 2017 were compared relative to hospital market concentration measured by the Herfindahl-Hirschman Index in the hospital referral region. MAIN OUTCOMES AND MEASURES: The primary outcome was the change in size of surgical practices over the study period. Secondary outcomes included change in surgical practice market concentration and the place of service for provision of surgical care stratified by surgical practice size. RESULTS: From 2013 to 2017, the number of surgical practices in the US decreased from 10 432 to 8451. The proportion of surgeons decreased in practices with 1 (from 26.2% to 17.4%), 2 (from 8.3% to 6.6%), and 3 to 5 (from 18.0% to 16.5%) surgeons, and the proportion of surgeons in practices with 6 or more surgeons increased (from 47.6% to 59.5%). Hospital concentration was associated with an increase in the size of the surgical practice. Each 10% increase in the hospital market concentration was associated with an increase of 0.204 surgeons (95% CI, 0.020-0.388 surgeons; P = .03) per practice from 2013 to 2017. Similarly, a 10% increase in the hospital-level HHI was associated with an increase in the surgical practice HHI of 0.023 (95% CI, 0.013-0.033; P < .001). Large surgical practices increased their share of Medicare services provided from 36.5% in 2013 to 45.6% in 2017. Large practices (31.3% inpatient in 2013 to 33.1% in 2017) were much more likely than small practices (19.0% inpatient in 2013 to 17.7% in 2017) to be based in hospital settings and this gap widened over time. CONCLUSIONS AND RELEVANCE: Surgeons have increasingly joined larger practices over time, and there has been a significant decrease in solo, small, and midsize surgical practices. The consolidation of surgeons into larger practices appears to be associated with hospital market concentration in the same market. Although overall care appears to be more hospital based for larger practices, the association between the consolidation of surgical practices and patient access and outcomes should be studied.