Workforce Growth Without Reach: National Trends in Access to High-Volume Parathyroid Surgeons

Introduction

Patient outcomes after surgery are improved when operations are performed by high-volume surgeons. This is especially true for specialized endocrine operations, such as parathyroidectomy, for which there is a well-established association between high-volume surgeons and lower rates of postoperative complications and reoperations.¹ Despite this association, and the increasing rates of parathyroidectomy being performed each year, there is limited access to high-volume parathyroid surgeons for many Americans.² Over the last decade, in response to the growing burden of operative endocrine disorders, the number of endocrine surgery fellowship positions in the United States (U.S.) has increased. However, it is currently unknown how expansion in the number of endocrine surgeons has affected national access to high-volume endocrine surgical care. We aimed to evaluate distribution and trends in access to High-Volume Parathyroid Surgeons (HVPS) from 2013 to 2023 in the U.S.

Methods

The Medicare Physician & Other Practitioners by Provider and Service dataset from the Centers for Medicare & Medicaid Services (CMS) was utilized to identify HVPS in 2013 and 2023. A HVPS was defined as having performed >10 parathyroidectomies (CPT codes 60500, 60502) for Medicare fee-for-service (FFS) beneficiaries from January 1 to December 31^st in the year of interest. Providers were excluded if they were not MD/DO, or of a nonsurgical specialty. Average monthly enrollment of FFS beneficiaries in each U.S. County in 2013 and 2023 was identified using CMS Medicare Enrollment Dashboard. The zip codes of each surgeon and counties of each FFS beneficiary were converted to Core Based Statistical Areas (CBSAs) using U.S. Department of Housing and Urban Development crosswalk data. When available, CBSAs were grouped to Combined Statistical Areas (CSAs), which represent regions with strong economic/commuting ties. The change in number of HVPS and the HVPS-to-FFS-beneficiary ratio was calculated for each CSA or CBSA.

Results

Using CMS provider data, we identified a 25% increase in the number of HVPS from 2013 to 2023 (2013: n= 302; 2023: n= 380). The largest increase in HVPS occurred in the New York-Newark (n=16), Boston-Worcester-Providence (n=8), Los Angeles-Long Beach (n=8) and San Jose-San Francisco-Oakland (n=8) regions (Table 1). There were 24 (4.5%) regions that did not have a HVPS in 2013 that gained a HVPS by 2023, and 23 (4.3%) regions that had ≥1 HVPS in 2013 but decreased to 0 by 2023 (Figure 1). Overall, 63 of the 539 regions increased their number of HVPS; however, due to this increase occurring predominantly in areas with pre-existing HVPS (n=39/63, 62%), along with the concurrent decrease to 0 HVPS in 23 regions, the number of regions with a HVPS did not meaningfully change in the last decade (2013: n=118/539, 22%; 2023: n=119/539, 22%).

Table 1.

Trends in the Number of High-Volume Parathyroid Surgeons (HVPS) and the Ratio of HVPS to Medicare FFS Beneficiaries from 2013 to 2023.

Panel A. Largest Increase
Number of HVPS
Region (CSA/CBSA)	No. Providers 2013	No. Providers 2023	Net Increase
New York-Newark, NY-NJ-CT-PA	20	36	16
Boston-Worcester-Providence, MA-RI-NH	6	14	8
Los Angeles-Long Beach, CA	6	14	8
San Jose-San Francisco-Oakland, CA	8	16	8
Tampa-St. Petersburg-Clearwater, FL	3	10	7
Houston-Pasadena,TX	2	7	5
Atlanta-Athens-Clarke County-Sandy Springs, GA-AL	7	11	4
Chicago-Naperville, IL-IN-WI	10	14	4
Nashville-Davidson-Murfreesboro, TN	2	6	4
Phoenix-Mesa, AZ	4	8	4
Proportion of HVPS to 100k FFS Beneficiaries
Region (CSA/CBSA)	HVPS/100k FFS Beneficiaries 2013	HVPS/100k FFS Beneficiaries 2023	Ratio change
Tampa-St. Petersburg-Clearwater, FL	1.06	4.18	3.11
Nashville-Davidson-Murfreesboro, TN	1.15	3.74	2.59
Allentown-Bethlehem-East Stroudsburg, PA-NJ	0.00	2.56	2.56
Harrisburg-York-Lebanon, PA	0.80	3.33	2.54
Portland-Vancouver-Salem, OR-WA	1.13	2.83	1.70
Raleigh-Durham-Cary, NC	2.09	3.79	1.70
Milwaukee-Racine-Waukesha, WI	0.48	2.04	1.56
Sacramento-Roseville, CA	0.50	2.00	1.50
Houston-Pasadena, TX	0.49	1.97	1.48
San Jose-San Francisco-Oakland, CA	1.27	2.62	1.35
Panel B. Largest Decrease
Number of HVPS
Region (CSA/CBSA)	No. Providers 2013	No. Providers 2023	Net Decrease
St. Louis-St. Charles-Farmington, MO-IL	9	4	−5
Cape Coral-Fort Myers-Naples, FL	3	0	−3
Jackson-Vicksburg-Brookhaven, MS	4	1	−3
Las Vegas-Henderson, NV	4	1	−3
Orlando-Lakeland-Deltona, FL	4	1	−3
Billings, MT	2	0	−2
Birmingham-Cullman-Talladega, AL	2	0	−2
Fayetteville-Lumberton-Pinehurst, NC	2	0	−2
Greenville-Washington, NC	2	0	−2
Memphis-Clarksdale-Forrest City, TN-MS-AR	3	1	−2
Proportion of HVPS to 100k FFS Beneficiaries
Region (CSA/CBSA)	HVPS/100k FFS Beneficiaries 2013	HVPS/100k FFS Beneficiaries 2023	Ratio change
Las Vegas-Henderson, NV	2.62	0.67	−1.95
Cape Coral-Fort Myers-Naples, FL	1.80	0.00	−1.80
Memphis-Clarksdale-Forrest City, TN-MS-AR	2.08	0.83	−1.25
St. Louis-St. Charles-Farmington, MO-IL	2.80	1.75	−1.05
San Antonio-New Braunfels-Kerrville, TX	2.02	1.05	−0.96
Columbia-Sumter-Orangeburg, SC	0.82	0.00	−0.82
Orlando-Lakeland-Deltona, FL	1.05	0.30	−0.75
Salt Lake City-Provo-Orem, UT-ID	3.04	2.33	−0.71
Knoxville-Morristown-Sevierville, TN	1.60	0.93	−0.67
Oklahoma City-Shawnee, OK	1.35	0.73	−0.62

Figure 1.

Geographic Representation of the Ratio of High-Volume Parathyroid Surgeons (HVPS) to FFS Beneficiaries Across the U.S. in 2023 and changes in HVPS from 2013 based on Centers for Medicare & Medicaid Services Provider Utilization and Payment data.

Access to HVPS in regions with ≥100,000 Medicare FFS beneficiaries, ranged from 0 to 3 HVPS per 100,000 beneficiaries in 2013, and 0 to 4.2 HVPS per 100,000 beneficiaries in 2023. From 2013 to 2023, the region with the largest increase in HVPS-to-FFS-beneficiary ratio was Tampa-St.Petersburg-Clearwater, FL (2013: 1.06; 2023: 4.12), and the region with the largest decrease in HVPS-to-FFS-beneficiary ratio was Las Vegas-Henderson, NV (2013: 2.62; 2023: 0.67) (Table 1).

Discussion

Although the overall number of HVPS has increased by 25% in the last decade, access has not necessarily expanded due to surgeons being predominately added to large metropolitan areas with pre-existing access to high-volume surgeons and concurrent loss of HVPS from areas with already low access.

The association between parathyroid surgeon volume and improved operative outcomes is well established.¹ Given that geographic proximity is a key determinant of healthcare access, persistent gaps in proximity to high-volume surgeons may meaningfully influence access to specialized care. Our data demonstrated large regions of the U.S. with limited or no access to high-volume parathyroid surgical care, consistent with prior work by Graves et al., who found that 24% of Americans in 2020 did not have access to a society-affiliated endocrine surgeon within an hour drive of their home.² Our study builds on these results by using CMS operative volume data to more specifically identify and evaluate the geographic distribution of high-volume surgeons, which is directly relevant to patient outcomes. These results offer the first characterization of a trend in HVPS distribution in the U.S., which has implications for health care access and highlights opportunities for a new geographic focus of endocrine surgery care.

There is a known shortage of surgeons in rural America, and the specialization of care may only be exacerbating this issue. In the U.S., the majority of endocrine operations are performed by general surgeons, many of whom do not perform a large volume of parathyroidectomies.³ Despite this apparent need for fellowship-trained endocrine surgeons, coinciding with a steady increase in the number of endocrine surgery fellowships in the last decade, one-third of graduating fellows report difficulty finding a job and over half end up taking jobs at the residency or fellowship in which they trained, which are almost all located in major metropolitan areas.^4,5 Whether this is a product of surgeon preference or job availability is unknown, but it is clear that this is an opportunity for an improved strategy to identify and highlight job market opportunities in areas that are more diverse in terms of geography, hospital affiliation and rural status. While it is likely unrealistic to expect a high-volume parathyroid surgeon in every CBSA, even modest expansion in geographic distribution could meaningfully improve access. Intentional regional care models, built on coordinated referral networks and partnerships with endocrinologists and primary care clinicians, could facilitate hybrid virtual and in-person care delivery structures to extend specialty expertise across broader catchment areas without requiring permanent local presence. Given the generally nonurgent nature of parathyroid surgery, it may be particularly well suited to such models. Potential strategies to operationalize such models include structured hub-and-spoke networks, rotating outreach clinics and teleconsultation pathways that facilitate centralized surgical care with decentralized pre- and postoperative management.^6,7

One limitation of this study is the use of only Medicare FFS data to identify HVPS. However, given PHPT primarily affects older adults likely to be Medicare beneficiaries, we believe this method likely captures the majority of U.S. HVPS. Another limitation is that we are unable to characterize if new HVPS from 2013 to 2023 represent endocrine surgery fellowship graduates or providers later in their career who have grown their practice. However, regardless of the surgeon’s stage in career, we believe these trends are relevant to discussions about surgical care needs of rural areas and the strategies to address them within the current fellowship training framework. Additionally, because the CMS data include only surgeons who performed ≥10 parathyroidectomies for Medicare beneficiaries and lack patient-level outcome data, we were unable to determine the proportion of procedures performed by high-volume surgeons or assess whether geographic access to high-volume care was directly associated with differences in clinical outcomes, despite prior evidence linking surgeon volume to improved outcomes.¹

Although the number of endocrine surgeons is increasing, these trends suggest that high-volume care will continue to be concentrated in already high-access metropolitan areas unless there is a concerted effort to address gaps in access across the country. This dichotomy of expansive low-access areas in the U.S. alongside concerns for a saturated endocrine surgery job market highlights an opportunity for targeted interventions to increase the presence of HVPS in low-access areas and improve access to high-value endocrine surgical care.