Potential Role for Assistant Physicians in Addressing the Physician Shortage

ABSTRACT

Given the fixed supply of residency training slots, pathways to increasing physician supply are limited. We assess use of the novel assistant physician (AP) status and the early impact of regulatory changes in Missouri. We find limited impacts of APs on supply, with a substantial majority (80.2%) of licensed APs not reporting a practice address and declining numbers of new licenses in recent years. We discuss implications and potential changes to increase health care supply through an AP pathway.

Am J Manag Care. 2026;32(7):In Press

Takeaway Points

• We assessed assistant physician (AP) use and the impact of regulatory changes in Missouri to study the impact of APs on health care shortages.
• A substantial majority (80.2%) of licensed APs are not actively practicing.
• After the 2023 AP law was enacted, tightening eligibility requirements, the share of APs from Caribbean medical schools decreased sharply and the share from non-US, non-Caribbean medical schools increased, suggesting that new accreditation requirements were impactful.
• We conclude that APs are having limited impact on health care supply and that changes to the AP pathway are needed given existing supply bottlenecks.

Recent projections estimate that the US will face a shortage of up to 86,000 physicians by 2036.¹ Given the fixed supply of residency training slots, the pathways to increasing physician supply are limited. One potential solution is to expand use of assistant physicians (APs)—medical school graduates who do not match into a residency program and are licensed to practice under a collaborative practice agreement with a physician.^2,3 The increased use of APs, for whom licenses are currently issued in 11 states, could improve access to care, especially in underserved areas, and provide a career path for the increasing number of physician graduates who have not completed residency training.

The integration of APs into practice has not been without challenges. The creation of APs has been targeted at immediately relieving health care shortages through AP care provision. There has been no clear pathway for transitioning from being an AP to a being a permanent part of the medical system outside successfully matching into residency in a later year. Furthermore, in response to quality concerns regarding some APs and an instance of fraud,⁴ Missouri amended its AP legislation in 2023 to restrict applicants to accredited medical schools while limiting the term of APs to 3 years.⁵ To assess AP use and the early impact of these regulatory changes, we examined the demographics, licensing patterns, and employment settings of APs in Missouri between 2017 (when the first AP law took effect) and December 2024 (after the restrictive legislation took effect in 2023).

METHODS

Data from the Missouri Board of Registration for the Healing Arts⁶ were used to identify AP name, medical school attendance, license issuance and expiration dates, and business address as of December 31, 2024. We examined AP licenses granted before and after Missouri’s 2023 legislation that was effective August 2023 for active and lapsed license-holders. Medical schools were defined as US-based, Caribbean-based (popular among US students not admitted to US medical schools), and foreign-based (all non-US and non–Caribbean-based) and were classified by the authors.

RESULTS

Number of APs and Licensure

Of the 308 currently licensed (39%) and 489 previously licensed (61%) APs between 2017 through 2024, 158 (19.8%) had an associated practice address in January 2025. Following a peak in 2020, issuance of new AP licenses began declining before Missouri’s 2023 legislation took effect (Figure). The total number of active APs in Missouri decreased by 30.5% from 443 in early 2022 to 308 at the end of 2024.

AP Education

Ten percent of APs attended a US medical school, 39% attended Caribbean medical schools, and 52% attended other foreign-based medical schools (Table). After the 2023 AP law was enacted, the share of APs from Caribbean medical schools decreased from 41% to 11% and the share from foreign-based medical schools increased from 49% to 80%, suggesting that new accreditation requirements were impactful in changing the composition of APs. However, the share of APs from US-based medical schools (10%) did not change.

DISCUSSION

Expanding access to primary care is an important policy goal with strong bipartisan political and multistakeholder support. Several practical challenges—including fixed supply of training positions—contribute to the limited number of achievable short-term solutions to solve patient access challenges, especially in underserved areas. Although APs have the potential to alleviate health care shortages, our findings suggest that a substantial majority (80.2%) of licensed APs do not report a practice address, implying that many are not actively providing care. Potential bottlenecks include a need for supervising physicians and the lack of Medicare reimbursement for care provided by APs,⁶ limiting the incentives for their uptake.

AP programs were designed to provide medical school graduates who do not match into a residency program a temporary pathway before reapplying to residency rather than creating permanent positions. However, because most APs do not ultimately match into residency programs and greater rates of APs matching into residency does not increase the supply of residency slots, their greater integration outside traditional residency training may help alleviate shortages. For example, an earlier version of Missouri’s 2023 legislation provided APs in good standing automatic eligibility for licensure as physician assistants after 3 years without additional requirements.⁷ Previous attempts to transition unmatched physicians to becoming midlevel providers have been unsuccessful because of a lack of equivalent clinical experience and parallel education for unmatched physicians.⁸ However, the AP pathway may be more promising than past efforts because it provides clinical experience. AP supervision could be explicitly designed with a pathway leading into other nonphysician clinical roles or to completion of physician training to enhance access to care.

The changes to the AP population after the 2023 regulatory changes show how sensitive this workforce is to accreditation requirements. After the 2023 regulation, the number of APs who were graduates of Caribbean medical schools decreased, and most APs were graduates of non-US, non-Caribbean medical schools. This may be consistent with noncitizens matching into US-based residencies at lower rates.⁹

Missouri’s experience with APs can help inform future policy decisions. Most APs are foreign medical graduates, especially after the 2023 legislation. Many states are responding to physician shortage issues by lowering the barriers to international physicians practicing in the US. Eighteen states have enacted legislation allowing international physicians to practice in the US without repeating residency training.¹⁰ Additionally, the American Board of Internal Medicine recently introduced a special consideration pathway for foreign residents to earn US specialization.¹¹ Such policies may provide a more immediate increase to physician supply, although any change to the H-1B visa policy can have important implications.

Limitations

There are several limitations to our study. We could not observe where APs worked after matching into residency or after exiting the clinical workforce in the Missouri Board of Registration for the Healing Arts data. We did not have data on the physicians who supervise the APs or on hours worked.

CONCLUSIONS

While pathways to expand the number of primary care clinicians are being contemplated, the use of APs could be considered as a path to expanding midlevel supply in underserved areas and to encouraging people to remain in the health care workforce.

Author Affiliations: Independent researcher (DS), New York, NY; Center for Value-Based Insurance Design (AMF), Ann Arbor, MI; Department of Internal Medicine, University of Michigan (AMF), Ann Arbor, MI.

Source of Funding: None.

Author Disclosures: Dr Fendrick reports receiving consulting fees from AbbVie, Better Medicare Alliance, Centivo, Clover Insurance Company, Community Oncology Alliance, eebu health, Elektra Health, Employee Benefits Research Institute, Exact Sciences, GRAIL, Hopewell Fund, Johnson & Johnson, Medtronic, MedZed, Merck, Mother Goose Health, Phathom Pharmaceuticals, Proton Intelligence Inc, Sempre Health, Sera Prognostics, Silver Fern Health, Virginia Center for Health Innovation, Washington Health Benefit Exchange, and Wellth, and serving as a partner for VBID Health and co–editor in chief of The American Journal of Managed Care. Dr Schwartzman reports no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.

Authorship Information: Concept and design (DS); acquisition of data (DS); analysis and interpretation of data (DS, AMF); drafting of the manuscript (DS); critical revision of the manuscript for important intellectual content (DS, AMF); statistical analysis (DS); and supervision (AMF).

Address Correspondence to: David Schwartzman, PhD, 175 W 87th St, New York, NY 10024. Email: dv.schwartzman@gmail.com.

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