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JAOA/AACOM Medical Education  |   September 2020
Practice Locations of Michigan Ophthalmologists as a Model to Compare Practice Patterns of DO and MD Surgical Subspecialists
Author Notes
  • From the Department of Ophthalmology at Loma Linda University in California (Dr Ahmed); Beaumont Taylor Ophthalmology in Michigan (Dr Price); Ear Nose and Throat Associates in Grand Blanc, Michigan (Dr Robbins); and Trinity Health Network in Williston, North Dakota (Dr Braich). 
  • Financial Disclosures: None reported. 
  • Support: This article was supported by an unrestricted grant by the American Osteopathic Colleges of Ophthalmology and Otolaryngology–Head and Neck Surgery Foundation, which was used to purchase the American Medical Association Physician Masterfile. 
  •  *Address correspondence to Harris Ahmed, DO, MPH, 11370 Anderson St, #1800, Loma Linda, CA 92354. Email: harris.ahmed@mybcom.org, harrislakers123@gmail.com
     
Article Information
Ophthalmology and Otolaryngology
JAOA/AACOM Medical Education   |   September 2020
Practice Locations of Michigan Ophthalmologists as a Model to Compare Practice Patterns of DO and MD Surgical Subspecialists
The Journal of the American Osteopathic Association, September 2020, Vol. 120, 568-574. doi:https://doi.org/10.7556/jaoa.2020.090
The Journal of the American Osteopathic Association, September 2020, Vol. 120, 568-574. doi:https://doi.org/10.7556/jaoa.2020.090
Web of Science® Times Cited: 1
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 al12 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 al11 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. 
Methods
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 χ2 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. 
Results
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. 
Figure 1.
Illustration of geographic distribution of ophthalmologists in Michigan in 2018. Red represents osteopathic physicians and yellow represents allopathic physicians. The numbers inside the circles represent the total number of ophthalmologists in that community/location/area. The colored area along the diameter of the circles represents the proportion of osteopathic physicians or allopathic physicians. that community. No number inside these circles denotes that there is only 1 ophthalmologist in the community.
Figure 1.
Illustration of geographic distribution of ophthalmologists in Michigan in 2018. Red represents osteopathic physicians and yellow represents allopathic physicians. The numbers inside the circles represent the total number of ophthalmologists in that community/location/area. The colored area along the diameter of the circles represents the proportion of osteopathic physicians or allopathic physicians. that community. No number inside these circles denotes that there is only 1 ophthalmologist in the community.
Figure 2.
Distribution of osteopathic and allopathic ophthalmologists in Michigan by community population size. According to the US Census Bureau, urbanized areas have populations >50,000; urban clusters have populations between 2500-49,999; and rural areas have populations <2500.
Figure 2.
Distribution of osteopathic and allopathic ophthalmologists in Michigan by community population size. According to the US Census Bureau, urbanized areas have populations >50,000; urban clusters have populations between 2500-49,999; and rural areas have populations <2500.
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. 
Discussion
The data reveal statistically significant differences between the practice locations of DO and MD ophthalmologists in Michigan, with DO ophthalmologists being more likely than MDs to practice in smaller and rural communities. Although the absolute number of MDs in smaller communities is higher than the absolute number of DOs, these numbers reflect that MDs outnumber DO ophthalmologists by a ratio of 6.5 to 1 in Michigan. More meaningful conclusions can be drawn by comparing the relative proportions. The results show that more MDs practice in larger communities and urban areas by proportion, and more DOs practice in nonurban, smaller, and more rural communities by proportion. These findings are similar to trends seen with other DO surgical subspecialists, such as otolaryngologists.11 There is a need for surgical subspecialists, such as ophthalmologists, in rural areas. The results of the current study indicate that DO ophthalmologists by proportion are more likely to practice in smaller, more rural communities. Michigan's ophthalmologist population may, therefore, serve as a useful model for examining strategies to enhance the presence of ophthalmologists in smaller and rural populations. 
Nationwide, osteopathic physicians have approximately 1.5 times greater probability of practicing in a rural area compared with other physicians.17 There may be many reasons for the differences in practice locations between DOs and MDs. One such reason is that many osteopathic medical schools are not located in metropolitan areas and are often in medically underserved areas.18,19 Rural training has been well established as a significant positive influence on rural practice locations. In addition, osteopathic medical students traditionally tend to be older than MD students,20 and many DO medical schools have rural tracks or clincs.21,22 These characteristics are well established to influence practice location and have contributed to more primary care DOs than MDs practicing in rural areas.10 Medical school location in underserved areas, older age, and increased exposure to rural tracks may also be driving forces for surgical subspecialist DOs, such as ophthalmologists, in Michigan to practice in smaller and more rural communities. 
Training in community settings for residency may be an additional driver behind the higher proportion of DO ophthalmologists practicing in smaller communities in Michigan. Chen et al23 showed a “negative relationship between the number of specialties trained (at an institution) and graduates practicing in rural areas.” All of the formerly AOA-accredited ophthalmology residencies in Michigan that have achieved initial accreditation by the ACGME are in community-based facilities.24 Also, traditionally ACGME-accredited ophthalmology residencies in Michigan are all in larger cities (4 of 4 in urbanized areas), whereas the formerly AOA-accredited ophthalmology residencies were largely based in smaller cities (3 of 4 programs in cities with a population ≤49,999).24,25 It is worth mentioning that existing data suggest that surgeons trained in nonuniversity community-based residencies have similar outcomes to those trained in large university centers in big cities with no significant differences in patient mortality, complications, or length of stay.26 In light of trends revealing that DO ophthalmologists in Michigan tend to practice in smaller and rural locations, preserving or emulating former AOA training programs could be a viable solution toward addressing rural surgical subspecialist shortages. 
The fact that only 2 of the 4 formerly AOA-accredited ophthalmology residencies in Michigan have successfully reached initial accreditation status by the ACGME suggests that the implications of the single GME on osteopathic surgical subspecialties may not have been adequately considered. The reasons for the vulnerability of formerly AOA-accredited ophthalmology programs in the single GME should be researched further. With 2 of the 4 formerly AOA-accredited ophthalmology programs closing down and the struggle DOs historically face in the San Francisco match for ACGME residencies, a decline may be seen in the number of DO ophthalmology graduates in the state of Michigan.13,14 A decline in DO ophthalmologists in Michigan may further exacerbate health care disparities with respect to ophthalmologic care, such as worse consequences and disease progression due to reduced access to ophthalmologists, particularly within rural areas and smaller communities. 
Limitations of the study include that our work is based on a cross-sectional study design; thus, long-term predictability or causation cannot be determined. Additionally, we did not analyze other variables, such as sex, age, ethnicity, or other factors that may influence location of practice. However, it is important to note that existing data suggest that variables such as age and sex do not play a significant role in the practice patterns of surgical subspecialists.27 Last, we selected Michigan as the model for this study because of its higher proportion of DOs; however, Michigan may not be representative of other states. 
Conclusion
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. 
Author Contributions
All authors provided substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; all authors drafted the article or revised it critically for important intellectual content; all authors gave final approval of the version of the article to be published; and all authors agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. 
Acknowledgments
We thank Abraham Wheeler, BE, for contributions toward the literature review. 
Reference List
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Figure 1.
Illustration of geographic distribution of ophthalmologists in Michigan in 2018. Red represents osteopathic physicians and yellow represents allopathic physicians. The numbers inside the circles represent the total number of ophthalmologists in that community/location/area. The colored area along the diameter of the circles represents the proportion of osteopathic physicians or allopathic physicians. that community. No number inside these circles denotes that there is only 1 ophthalmologist in the community.
Figure 1.
Illustration of geographic distribution of ophthalmologists in Michigan in 2018. Red represents osteopathic physicians and yellow represents allopathic physicians. The numbers inside the circles represent the total number of ophthalmologists in that community/location/area. The colored area along the diameter of the circles represents the proportion of osteopathic physicians or allopathic physicians. that community. No number inside these circles denotes that there is only 1 ophthalmologist in the community.
Figure 2.
Distribution of osteopathic and allopathic ophthalmologists in Michigan by community population size. According to the US Census Bureau, urbanized areas have populations >50,000; urban clusters have populations between 2500-49,999; and rural areas have populations <2500.
Figure 2.
Distribution of osteopathic and allopathic ophthalmologists in Michigan by community population size. According to the US Census Bureau, urbanized areas have populations >50,000; urban clusters have populations between 2500-49,999; and rural areas have populations <2500.