The geographical structure of medical and surgical care delivery is associated with not just access to, but also potentially quality of, care, as suggested in the study by Tsai et al.1 The authors used a novel Medicare database to examine the distribution of general surgeons across billing entities and within hospital referral regions (HRRs) and found a trend toward greater concentration of surgeons into larger organizations.1
The structure of markets for general surgery services in the United States has changed over time for many reasons. The uneven changes in population, such as how the South and West have experienced large and rapid regional increases in populations, have created complex, diffuse markets for all medical and surgical services. The North and Midwest have experienced a reconcentration of population in many older urban areas where hospitals have been traditionally located. All regions of the US have experienced the emergence of so-called edge cities2 that attract complex service centers and expansion facilities, including hospitals and medical office campuses. The combination of these 2 macro trends has modified the geography of surgical care markets.
Rural places have generally been left behind by these trends, with their hospitals often closing if not merging and transforming into a different form of organization.3 Perhaps more importantly, as Tsai et al1 point out, the organization of general surgical practice has changed as practices have merged into larger and larger structures—another factor that can have implications for the viability of rural hospitals.4
The use of HRRs for studying medical care delivery markets is seen as almost a criterion standard for the analysis of competition, but the HRRs from the Dartmouth Atlas of Health Care used by Tsai et al1 and elsewhere in the literature reflect market structures of 2008 and earlier and have other inherent characteristics that may call for caution in interpreting data and trends based on them.5 There are options for the construction of market areas as they apply to specialist and general physician services, such as contemporary HRRs as proposed by Jia et al,6 and commercial products offered by private firms, such as IQVIA (formerly IMS), but no similar criterion standard has emerged for the assessment of physicians in generalist or specialty markets, with one exception being for neonatal intensive care proposed by Goodman et al,7 despite the powerful statistical methods and large data sets readily available to health services researchers. There have been hundreds of hospital mergers and closures since the Dartmouth version of the HRRs used by Tsai et al1 was constructed. This drift may affect the conclusions that can be drawn from the study by Tsai et al,1 since areas may have changed dramatically in some parts of the United States and little in others.
The analysis used by Tsai et al1 makes creative use of the Medicare Data on Provider Practice and Specialty (MD-PPAS) data file of individual surgeon data aggregated by the Centers for Medicare & Medicaid Services across the Dartmouth HRRs. This data set has been underused in studies of medical or surgical market structures. The data from the MD-PPAS closely agree with data on general surgeon supply as reported in other inventories, such as the American Medical Association’s Physician Masterfile, and could be used for the analysis of other physician specialties and their billing organizations. While the study by Tsai et al1 focuses on general surgery, a logical extension of the analysis would examine the complexity of the physician supply, especially subspecialty surgeon supply, in each region. General surgeons may be integrating into more complex (multispecialty) or less complex (general surgery–focused) organizations, and that may affect both the competitive profile of an area as well as the overall pattern of use of surgical services. Further examination of the MD-PPAS file provides a unique opportunity to relate the organizational and regional structures in which general surgeons practice to their productivity and content of practice as well as patient and population outcomes. The practice of general surgery appears to be consolidating, parallel to trends among all physicians, and its correlation with measures of market concentration suggests less competition. Therefore, Tsai et al1 rightly encourage assessing the patient access and quality of care outcomes associated with these trends.
Published: April 28, 2021. doi:10.1001/jamanetworkopen.2021.8090
Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2021 Ricketts TC. JAMA Network Open.
Corresponding Author: Thomas C. Ricketts, PhD, MPH, Cecil G. Sheps Center for Health Services Research, The University of North Carolina at Chapel Hill, 725 M. L. King Jr Blvd, Chapel Hill, NC 27599 (firstname.lastname@example.org).
Conflict of Interest Disclosures: None reported.
Ricketts TC. Place and Population Matter in General Surgeon Location and Practice Structure. JAMA Netw Open. 2021;4(4):e218090. doi:10.1001/jamanetworkopen.2021.8090
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