Abstract
Context:
While existing data demonstrate that osteopathic physicians (ie, DOs) in primary care are more likely than allopathic physicians (ie, MDs) to practice in rural areas, no data exist on practice patterns of DO surgical subspecialists, such as ophthalmologists. Michigan has a relatively high number of DOs and, formerly, the most osteopathic ophthalmology residency programs in the United States. Analyzing the distribution of ophthalmologists in Michigan may reveal patterns and predict trends about the geographic distribution of DO surgical subspecialists across the country.
Objective:
To compare geographic distributions of DO and MD ophthalmologists in Michigan and identify differences in community size and type (eg, urbanized area, urban cluster, or rural area) of practice.
Methods:
A list of Michigan's ophthalmologists practicing in 2018 was developed using the Centers for Medicare and Medicaid Services, the American Osteopathic College of Ophthalmology, and the American Medical Association data sets. DOs and MDs were then analyzed by determining where each ophthalmologist practiced, identifying the size and type of community in which they practiced, and finally by comparing the percentage of DOs and MDs who practiced in various community sizes and each community type as defined by the US Census Bureau. An χ2 analysis was used to determine whether a difference existed in practice locations.
Results:
A total of 643 ophthalmologists practiced in Michigan in 2018, including 85 DOs and 558 MDs. A greater proportion of DOs worked in rural areas and urban clusters (57 [67%]), whereas a greater proportion of MDs worked in urbanized areas (368 [66%]). Of DOs, 28 (33%) practiced in cities with a population of at least 50,000 vs 371 MDs (66%). Fourteen DOs (16%) practiced in communities with a population of at least 100,000 vs 207 MDs (37%). χ2 analysis showed a significant difference in the geographic distribution of ophthalmologist DOs and MDs (P<.01).
Conclusion:
Higher proportions of DOs practice ophthalmology in smaller, more rural Michigan communities compared with MDs, implying that a subgroup exists that tends to serve underserved areas.
With the 2015 transition to a single graduate medical education accreditation system (single GME), there has been a reduction in residency programs in surgical subspecialties with osteopathic leadership.
1,2 A useful case study to understand patterns and trends regarding the distribution of osteopathic specialists is the ophthalmologist population in the state of Michigan. Michigan has 7 medical schools, 1 of which is an osteopathic institution with 3 locations.
3 Michigan also features a higher proportion of practicing osteopathic physicians (ie, DOs) compared with most other states in the country.
4 Additionally, before the single GME transition that began in June 2015, there were 4 ophthalmology programs in Michigan accredited by the American Osteopathic Association (AOA), the most of any state in the nation. An analysis of the distribution of ophthalmologists in Michigan may help to understand and predict potential trends for the geographic distribution of DO specialists across the country.
About 20% of the US population lives in a small or rural area, which is defined by the US Census Bureau as a community with fewer than 2500 residents.
5 Lack of access to primary care and specialty physicians in rural locations negatively affects health care outcomes for patients.
6 Incentives have been in place for primary care physicians to practice in rural settings, but there remains a shortage of specialists, such as ophthalmologists.
7-9 Relative to urban cities, rural areas and communities with smaller populations have poorer vision outcomes and lower rates of basic ophthalmologic surgery, such as cataract surgery, owing to decreased access to ophthalmologists.
9 Currently, nationwide trends are contributing to outpatient specialist shortages in rural areas, including the rising cost of running a medical practice, excessive billing documentation, government regulations, and a reluctance to practice in rural settings, which have led to the acquisition of practices by private firms or hospital networks.
10,11
Fordyce et al
12 demonstrated that a higher percentage of primary care DOs practice in rural locations compared with allopathic physicians (ie, MDs) (20.5% vs 14.9%, respectively). Ophthalmologists represent a small subset of DOs nationwide, and few osteopathic medical students have been accepted into ophthalmology programs accredited by the Accreditation Council of Graduate Medical Education (ACGME), historically.
13,14 For example, there was a 38% match rate for 42 osteopathic seniors who applied to an ACGME ophthalmology program in 2019 vs 85% for 512 allopathic seniors.
13,14 Additionally, the single GME has brought significant shifts in former AOA-accredited residencies. For example, while 90% of former pediatrics programs and 92% of anesthesia programs that were previously accredited by the AOA have achieved initial ACGME accreditation, the proportion is much lower for ophthalmology programs (46%).
1,15 Fewer ophthalmology programs with osteopathic leadership may lead to fewer opportunities moving forward for osteopathic medical students to pursue ophthalmology, diminishing an already small number of DO ophthalmologists.
Considering the declining number of residency opportunities for osteopathic ophthalmology students, and ensuring that future accreditation decisions do not adversely affect access to care in underserved areas, policymakers should consider the practice trends of DO and MD ophthalmologists. Evidence-based models are needed to guide policymakers and future decisions regarding approval or additions to ophthalmology training programs. Griffith et al
11 conducted a study revealing that, by proportion, a greater percentage of DO otolaryngologists practiced in smaller cities across Pennsylvania compared with MDs. Their results raise the question of whether Michigan ophthalmologists tend to practice in smaller cities, as it could reveal a tendency among DO surgical subspecialists to serve smaller communities, similar to DO primary care physicians.
Understanding practice trends is especially important now that several formerly AOA-accredited ophthalmology programs are closing down, as access to ophthalmologic care in rural and smaller communities may be affected by closures if DO ophthalmologists tend to serve these vulnerable communities. The aim of the current study was primarily to compare the geographic distribution of DO and MD ophthalmologists in Michigan. The secondary aim was to identify differences in the community sizes and types (ie, urbanized area, urban cluster, and rural area) in which these physicians practice.
This study was exempt from institutional review board review. This observational study stratified a cross-sectional sample of ophthalmologists in the state of Michigan by their degree (DO vs MD) and by the size and type of geographic area in which they primarily practiced.
A list of ophthalmologists practicing in Michigan in 2018 was compiled from the most recent data available from 3 sources: the Centers for Medicare and Medicaid Services, the American Osteopathic Colleges of Ophthalmology and Otolaryngology-Head and Neck Surgery Masterfile, and the American Medical Association Physician Masterfile. These data sets allowed for the exclusion of residents, fellows, and nonclinical health care professionals. Then, populations of the primary practice locations for all ophthalmologists were obtained by using the most current census data available (2010). The data were then used to stratify ophthalmologists by their affiliation as DOs and MDs.
The US Census Bureau separates urban areas into 2 categories: urbanized areas (population ≥50,000) and urban clusters (population between 2500-49,999).
15 Rural areas are defined as having a population of fewer than 2500. Using these definitions, we stratified ophthalmologists once again by the size of the community in which they practiced. A χ
2 analysis was performed to compare each group by their proportions. Statistical significance was defined as
P<.05. The investigators were interested in observing whether the number of DO and MD ophthalmologists (1) varied by geographic distribution or (2) varied by practice location.
Furthermore, the percentages of DO and MD ophthalmologists were aggregated into smaller groups based on the following population strata: below 3125; 3125 to 6249; 6250 to 12,499; 12,500 to 24,999; 25,000 to 49,999; 50,000 to 99,999; 100,000 to 199,999; and 200,000 or more.
The distribution of all practicing DO and MD ophthalmologists is shown in
Figure 1. The data revealed that 643 ophthalmologists were practicing in the state of Michigan in 2018. Of these, 85 (13%) were DOs and 558 were MDs. Of the DOs identified, 57 (67%) practiced in communities with a population of 49,999 or less vs 187 (37%) of MDs (
P<.01). Twenty-eight DOs (33%) practiced in communities with a population of at least 50,000 vs 371 MDs (66%) (
P<.01). Additionally, 14 DOs (16%) practiced in cities with a population of at least 100,000 vs 207 MDs (37%) (
P<.01).
Figure 2 shows the distribution of DO and MD ophthalmologists by the size of the population in their primary community of practice.
Among DO ophthalmologists in Michigan identified, 28 (33%) practiced in urbanized areas (≥50,000) compared with 371 MDs (66%) (χ2=31.27, P<.01). Regarding urban clusters, this difference was also significantly large, with 55 DO (65%) vs 187 MD (34%) ophthalmologists (χ2=27.68, P<.01). In rural areas of Michigan, 2 of 85 DOs (2%) and 0 MDs were found to practice.
We found a higher proportion of DO than MD ophthalmologists in Michigan practice in locations with smaller population sizes, and, therefore, DO ophthalmologists may provide a pool of surgeons that can serve rural and smaller communities. Discontinuation of several AOA ophthalmology residencies may decrease health care access in less-populated communities, as it may diminish the pool of graduating DO ophthalmologists, who tend to serve in less populated communities. Furthermore, such a shortage of ophthalmologists in rural areas may lead to poorer health outcomes. The ACGME, AOA, American Academy of Ophthalmology, American Osteopathic College of Ophthalmology, and government-regulating bodies should take this into consideration as they continue to improve health care access in the United States.