I thank the readers who have emailed comments and questions to The Curious Economist. Recently, several curious readers asked two important anesthesia workforce-related questions, and my responses are the topics of this month’s column. The inquiries were:
- What are the trends in anesthesia professionals and other physicians leaving the workforce?
- How many anesthesia-related group practices employ only nurse anesthetists?
I examined data from the Centers for Medicare & Medicaid Services (CMS) National Downloadable Files (NDFs) between April 2014 and August 2022 (asamonitor.pub/3tDFACx). These files include National Provider Identifiers (NPIs) and related information for physician and nonphysician specialties that submitted Medicare fee-for-service claims in the previous six months (12 months for NDFs before February 2018). The information in each NDF includes the clinician’s name, credentials, specialty, address, gender, medical school, graduation year, affiliated group practice, and up to four hospitals associated with the Medicare claims. I excluded professionals not practicing in the conterminous U.S., Alaska, or Hawaii.
I identified clinicians who left the workforce (“drops”) based on the last year in which their NPIs were present in the NDFs. For example, if the final NDF month in which a clinician appeared was September 2020, I assigned the drop to 2020. However, if the last NDF month for a clinician was March 2021, then because of the six-month lookback period in the NDFs, the clinician might have dropped out of the workforce in late 2020 or early 2021. In this case, I assigned the drop to 2021, the year of the NDF. To address question #1 above, I compared the average number of drops during 2017-2019 with the number of drops in 2020 and 2021. I examined drops for the five physician and five nonphysician specialties with the highest number of drops in 2020 and 2021.
I also used the NDF data to address question #2 regarding nurse anesthetist-only group practices. The NDFs include the organization’s legal name and group identification number associated with the clinician’s practice. For some group practices, this represents a local or regional organization that is part of a large national group but operates with a different legal name and group identification number than those of the “umbrella” group under which it operates. Additional primary research is needed to identify component organizations within some large national groups. However, for small, medium, and most large groups, there is typically only a single organization name in the NDF.
I used the February 2018 and August 2022 NDF to identify nurse anesthetist-only groups and compare the two time periods. I defined a nurse anesthetist-only group as a group with at least three nurse anesthetists and no other clinicians. If a nurse anesthetist was associated with more than one group practice identifier, then the nurse anesthetist was split equally among the different groups. For example, if a nurse anesthetist was identified in two groups, then each group was allocated 0.5 of the nurse anesthetist; if three groups, then each would be allocated 0.33 of the nurse anesthetist, etc.
I. Trends in workforce “drops,” 2017-2021
Table 1 presents trends in the workforce drops in the top physician and nonphysician specialties ranked by the number of drops in 2020 and 2021. Anesthesiology ranked fifth among the physician specialties. Combined, nurse anesthetists and certified anesthesiologist assistants (CAAs) ranked fifth among the nonphysician specialties. Drops among anesthesia professionals between 2017 and 2021 are depicted in the Figure.
Among the top five physician specialties ranked by the number of drops, anesthesiology had the greatest percentage increase in the number of drops in 2020 over the 2017-2019 average (44.4%). Anesthesiology’s 49.7% increase in 2021 over 2017-2019 represented the second-highest percentage increase in the number of drops; obstetrics/gynecology had the highest percentage in 2021 (55.7%). Despite the relatively significant increases in the number of drops, anesthesiology had the second-to-lowest drops as a percentage of the specialty’s total number of physicians.
Similarly, among the top five nonphysician specialties, nurse anesthetists and CAAs combined had the highest-percentage increase in drops in 2020 over the 2017-2019 average (62.7%) and the second highest in 2021 (71.3%); nurse practitioners experienced an 87.8% increase in 2021 compared to 2017-2019. However, the drops in nurse anesthetists and CAAs represented the lowest percentage of clinicians in their specialties in 2020 and 2021, compared to the other four nonphysician specialties.
I used years since graduation as a proxy to examine differences between 2019 and 2021 in the age of the clinicians who dropped from Medicare billing (Table 2). Nurse anesthetists experienced the largest decline in mean years since graduation (3.3 years), followed by obstetrics/gynecology (3.1) and anesthesiology (2.3).
In an earlier column of The Curious Economist, I identified 2,620 “new” anesthesia professionals billing Medicare in 2021 NDFs (ASA Monitor 2022;86:1-11). In comparison, as presented in Table 1, there were 3,754 drops among anesthesia professionals in 2021, a net reduction of 1,134 clinicians. This trend is especially problematic in an era of increasing demand for anesthesia services.
II. Nurse anesthetist-only groups
Table 3 presents the top 20 states with nurse anesthetist-only groups, ranked by the number of nurse anesthetists in these groups. These top 20 states represented more than 80% of the nurse anesthetists in nurse anesthetist-only groups. Between 2018 and 2022, North Carolina and California had the largest increase in the number of nurse anesthetists in nurse anesthetist-only groups, and California had the highest-percentage increase (from 28 nurse anesthetists in 2018 to 195 nurse anesthetists in 2022). The number of nurse anesthetists in nurse anesthetist-only groups more than doubled in three other states between 2018 and 2022: Ohio, Washington, and Georgia. The most significant declines in the number of nurse anesthetists in nurse anesthetist-only groups occurred in South Carolina, Michigan, Texas, and Illinois.
Nurse anesthetists in nurse anesthetist-only groups represented 16% of the nurse anesthetists in the 2018 NDF and 14% of the nurse anesthetists in the 2022 NDF. The four largest nurse anesthetist-only groups were hospital-based, and each comprised more than 100 nurse anesthetists. Three of these four were in North Carolina and the other was in Alabama.
There was a substantial number of self-employed and other nurse anesthetists in nurse anesthetist-only entities with fewer than three nurse anesthetists, which, by definition, I excluded from the “group” analysis. Specifically, in 2018 there were 688 nurse anesthetists in 486 entities. In 2022, there were 1,299 nurse anesthetists in 887 entities with less than three nurse anesthetists.
I was curious about groups that were predominantly nurse anesthetists. Therefore, I examined groups with more than 20 nurse anesthetists that comprised anesthesiologists representing no more than 10% of the anesthesia professionals. In 2018, 18 of these nurse anesthetist-predominant groups accounted for 1,197 nurse anesthetists. By 2022, 26 groups accounted for 1,288 nurse anesthetists.
Not surprisingly, most of the nurse anesthetist-only groups are hospital-employed. More importantly, most of these nurse anesthetists, despite being in separate organizations, practice in the anesthesia care team with anesthesiologists. Nonetheless, an anesthesia care team representing two or more organizations may experience significant cultural challenges compared to a care team that is part of the same organization and economic unit. As a result, local anesthesia workforce market disruption may be more common in areas with higher proportions of nurse anesthetists in nurse anesthetist-only groups because their organizational culture and goals may not align with those of the anesthesiologists with whom they practice.
There are limitations to the data used in these analyses. First, the NDFs represent only clinicians who have billed Medicare in the past six (or 12) months. Second, there is some variability and potential inconsistencies among the biweekly data files. Still, the data reflect strong indicators of key anesthesia workforce issues. I look forward to revisiting these data in the future.
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