Disparities in Physician Access for Rheumatology, Dermatology, and Gastroenterology: A Systematic Review

ABSTRACT

Objectives: Substantial disparities in access to health care, including to physician specialists, hinder diagnosis, treatment, and outcomes for patients with immunological diseases; thus, more studies are needed to understand and address these disparities. This study aimed to evaluate factors associated with disparities in rheumatology, dermatology, and gastroenterology specialist access for patients with immunological conditions and the consequences of such disparities.

Study Design: Systematic literature review.

Methods: Studies published between 2017 and 2023 examining US adults (≥ 18 years) with key immunological conditions receiving care by rheumatologists, dermatologists, and gastroenterologists were systematically reviewed. Thematic analyses of qualitatively synthesized data were used to evaluate disparities in specialist access (defined under “5 A’s”: affordability, availability, accessibility, accommodation, and acceptability) and the associated clinical/economic outcomes.

Results: Specialist access disparities and related outcomes were inconsistently evaluated across the 46 included studies, with limited evidence in gastroenterology. Common factors associated with specialist access disparities in rheumatology and dermatology included rural residence, insurance type (primarily Medicaid), Black or Hispanic race and ethnicity, and low regional specialist density. Frequent outcomes of this low access included higher disease severity, higher hospital admission and readmission rates, and higher numbers of emergency department visits. Importantly, studies described ways to improve specialist access across the 5 A’s (eg, minimize structural barriers, use a multidisciplinary approach, promote telemedicine, increase health literacy, improve community partnerships).

Conclusions: Specialist access disparities were identified in rheumatology and dermatology. Conclusions in gastroenterology could not be inferred due to limited evidence. Evidence-based solutions are provided to address identified gaps in US health care.

Am J Manag Care. 2025;31(9):In Press

Takeaway Points

There is an urgent need to address disparities in specialist access for US patients with immunological conditions receiving care in rheumatology, dermatology, and gastroenterology. In this original systematic literature review, we identified the following:

• Disparities in specialist access and the outcomes of such disparities are inconsistently studied across US rheumatology, dermatology, and gastroenterology.
• Evidence-based solutions to improve specialist access include minimizing structural barriers, using multidisciplinary approaches, promoting telemedicine, increasing health literacy, and improving community partnerships.
• Recommendations herein may inform clinical and policy decisions, promote health care reform, expand specialist access, and ultimately improve real-world outcomes for patients with immunological diseases.

Recent social and political movements, as well as the devastating effects of the COVID-19 pandemic, have illuminated substantial disparities in access to and delivery of health care in the US, particularly among underserved populations.¹ As a result, a renewed focus has been applied to this issue, with both scientific and public health communities working to better identify existing health care disparities and to provide evidence-based strategies to close the gaps in US health care.² Health care disparities are preventable differences in individuals’ ability to achieve optimal health and are linked to social determinants of health (SDOH) (ie, the interrelated nonmedical factors that influence health risk and outcomes),³ including economic stability, education access, environment, social context, and—notably—health care access.⁴ Disparities in health care access are complex in nature and comprise several dimensions, including access to physician specialists, diagnostic procedures, and therapies. In this systematic literature review, we focus specifically on disparities in physician specialist access.

Many individuals in the US, including those from racially and ethnically diverse groups, those living in rural areas, and those with low socioeconomic status (SES), face barriers to health care access.^3,4 This limited access, when paired with other systemic health care inequities, is associated with worse patient outcomes; therefore, eliminating and preventing disparities in care access are key to achieving health equity and improving patient outcomes.^3,4 Despite the expanding availability of diagnostic and therapeutic options, patients with immunological diseases across rheumatology, dermatology, and gastroenterology often encounter obstacles, such as limited access to specialists, that can impede care.^5-7 For example, diagnosis, treatment initiation, and long-term clinical outcomes in patients with rheumatoid arthritis are dependent on early access to a rheumatologist.⁸ Yet there is a growing shortage of 3800 to 13,400 US medical specialists expected by the year 2034, including rheumatologists, dermatologists, and gastroenterologists, among others.⁹ Therefore, addressing disparities in health care access is a top priority for these specialties.

A comprehensive review of disparities in specialist access within rheumatology, dermatology, and gastroenterology does not currently exist. Thus, there is a need to assess what is known regarding disparities in specialist access,² identify gaps in existing evidence, and provide evidence-based solutions addressing disparities in specialist access across these spaces. Accordingly, we conducted a systematic literature review to investigate US health care disparities in access to rheumatology, dermatology, and gastroenterology specialists providing care for adults with immunological conditions. Our objectives were to (1) evaluate the patient, physician, and environmental factors/SDOH associated with disparities in specialist access and (2) assess the clinical and economic impacts associated with these disparities in specialist access.

METHODS

Systematic Literature Review

To identify the most recent and relevant literature, we searched the PubMed, Embase, and Web of Science databases for articles published between January 1, 2017, and September 30, 2022. Conference abstracts from February 16, 2021, through February 16, 2023, were obtained via Embase. Search strategies for each database are presented in eAppendix Tables 1 through 3 (eAppendix available at ajmc.com). Eligible studies were US based and focused on physician specialists (ie, rheumatologists, gastroenterologists, dermatologists) providing care for adults (≥ 18 years) diagnosed with common immunological conditions (eg, rheumatoid arthritis, psoriatic diseases, inflammatory bowel disease, systemic lupus erythematosus).¹⁰ Studies reported on disparities in access (defined under the “5 A’s” framework,¹¹ described later) and their associated effects on clinical and economic outcomes. Outcomes included delay in diagnosis, delay in treatment, physician cycling, disease-modifying antirheumatic drug cycling, corticosteroid cycling, disease progression, worsening of patient-reported outcomes, and utilization/health care resource use. eAppendix Table 4 presents the eligibility criteria for screening.

An author (S.K.) screened records at level 1 (titles and abstracts) and level 2 (full-text articles). One independent reviewer (Weyinmi Nuabor, MPH) checked records during each screening phase, and a second independent reviewer (Alisha Krumbach, PharmD) reconciled discrepancies as needed. Data from included studies were qualitatively synthesized, and a thematic analysis was used to identify disparities in specialist access and associated outcomes.

Theoretical Framework: The 5 A’s of Access

In 1981, Penchansky and Thomas¹¹ categorically defined access across 5 dimensions: (1) affordability describes patients’ ability and willingness to pay for medical services (eg, out-of-pocket costs); (2) availability is the presence of medical resources to meet patients’ needs (eg, diagnostic procedures); (3) accessibility includes the ease with which patients can physically reach their providers (eg, travel distance, transportation); (4) accommodation is the extent to which a provider meets patients’ constraints and preferences (eg, hours of operation); and (5) acceptability describes the extent to which patients are comfortable with their provider (eg, age, sex, social class, race, ethnicity) and vice versa.¹² The 5 A’s of access framework is well known and has been widely used in public health research.^11,13,14 Throughout our review, we use these 5 A’s to convey the multifaceted relationship between patients and disparities in specialist access.

RESULTS

We identified 595 records through database searches (Figure 1), of which 46 studies met the inclusion criteria for our literature review after screening. A total of 507 records were excluded after level 1 screening of titles and abstracts, and 42 records were excluded after the full-text review in level 2 screening. Most studies were excluded due to outcomes not meeting the inclusion criteria (eg, not pertaining to disparities in access).

Top Disparities in Specialist Access

In our review of the 46 included studies, we found that disparities in specialist access were not consistently evaluated across rheumatology, dermatology, and gastroenterology, nor were related clinical and economic outcomes. Among the 5 A’s of access (affordability, availability, accessibility, accommodation, and acceptability), accessibility was the most studied across rheumatologists and dermatologists, whereas acceptability and accommodation were the least studied (Table 1). Notably, limited studies were identified in gastroenterology, precluding detailed analyses in this field. Study summaries are presented in eAppendix Tables 5 through 9.

The factors that have been most frequently reported to result in disparities in specialist access—particularly for rheumatology and dermatology—include rural residence,^15-21 insurance type (primarily Medicaid),^5,6,15,22-25 Black or Hispanic race and ethnicity,^25-29 and low specialist density^20,21,29-32 (Figure 2). These data suggest that patients residing in rural areas, those with Medicaid insurance, and individuals of Black or Hispanic race and ethnicity may have less access to specialists. Other factors reported by at least 2 studies in rheumatology and/or dermatology included low SES,^15,22,25,30 living in the Midwest region,^20,25,27 homelessness,^33,34 and long travel distance.^18,35 All studies assessing disparities in specialist access are presented in Table 2.^5-7,15-40

Rural residence and low specialist density. Cyr et al¹⁸ noted that several barriers to dermatology care existed in a rural regional health system, including long delays to get appointments and long travel distance. Additionally, Nguyen and Bray²⁰ found that the average density of dermatology providers was lower in American Indian and Alaska Native (AIAN) communities than in the rest of the US, likely due to AIAN communities being mostly in rural areas. The shortage of dermatology providers and transportation to distant providers were also barriers to accessing dermatologic care for AIAN communities. Moreover, Tomtschik et al²¹ found that the supply of dermatologists in rural areas grew at less than half the rate of nonrural areas, meaning geographic disparities worsened.

Black or Hispanic race and ethnicity. Even when patients had uniform insurance coverage, Schletzbaum et al²⁷ found that race and ethnicity were associated with disparities in rheumatology care access. Similarly, in a study of rheumatoid arthritis, Riad et al²⁶ reported that Hispanic patients had a significantly longer median time until their first visit at an academic rheumatology center than did non-Hispanic patients. Rogers et al²⁸ found that Black patients were significantly less likely than White patients to visit a dermatologist for acne management, and Tripathi et al²⁵ likewise reported that Hispanic and Black patients were both less likely to receive dermatologic care compared with non-Hispanic White patients. Although Rehman et al²⁹ found that larger proportions of Black and Hispanic patients live in areas with low vs high density of dermatologists, most studies did not examine why Black or Hispanic patients were more likely to experience disparities in specialist access.

Insurance type (primarily Medicaid). Ogdie et al⁵ found that the proportion of patients with psoriatic arthritis or ankylosing spondylitis who saw a rheumatologist was much lower for patients with Medicaid than for patients with Medicare or commercial insurance. Similarly, Creadore et al⁶ found that patients with Medicaid had significantly lower success in obtaining dermatology appointments and had longer wait times than did patients with Medicare or commercial insurance. Lastly, Tripathi et al²⁵ found that patients with either Medicaid or Medicare and uninsured patients were all less likely to receive outpatient dermatology services than were privately insured patients. Insurance type may lead to disparities in specialist access because fewer specialists accept Medicaid or uninsured patients.^6,25 More studies are needed to understand why patients with particular insurance types have low specialist access.

Top Outcomes Associated With Disparities in Specialist Access

Clinical and economic consequences related to disparities in access to specialists are inconsistently studied (Table 1). Only 17 of the included studies (16 primary articles and 1 review) evaluated clinical or economic outcomes associated with low specialist access, and only 2 of these studies were in gastroenterology. Common outcomes linked to low access, based on studies in rheumatology and dermatology, included higher disease severity,^26,33,34,36 higher hospital admission/readmission rates,^15,16,22 and higher numbers of emergency department visits^22,26,34 (Figure 3). Studies assessing outcomes associated with low access to specialists are presented in Table 2.^5-7,15-40

Higher disease severity. In a study evaluating access to dermatological care for psoriasis management, patients reported improvements in disease severity due to better access to a provider.³⁶ Conversely, patients facing barriers to specialist access often have increased disease severity.^26,33,34 Highlighting this point, Riad et al²⁶ evaluated clinical outcomes on the basis of race and ethnicity in patients with rheumatoid arthritis. They found that both Hispanic and Black patients had significantly higher disease activity at baseline, indicated by Routine Assessment of Patient Index Data 3 scores and erythrocyte sedimentation rates.²⁶ Additionally, patients with inflammatory arthritis experiencing homelessness had more disease burden³³ and poorer disease control³⁴ than housed patients.

Higher use of hospital or emergency services. In rheumatology studies among patients with systemic lupus erythematosus, disparities in specialist access were associated with higher hospital admission/readmission rates and higher numbers of emergency department visits. Chandler et al²² reported that hospital admission rates were significantly higher in patients with low SES. Additionally, Schletzbaum et al¹⁵ found that patients retained in outpatient lupus care prior to hospitalization had lower rates of hospital readmission but that patients living in rural areas or patients with low SES (indicated by Medicaid eligibility) had lower odds of being retained in care prior to hospitalization. In a rheumatology study assessing homelessness as a barrier to specialist access, patients experiencing homelessness had lower adherence to clinic appointments and higher use of emergency medical services than patients not experiencing homelessness.³⁴ Chandler et al²² also reported that patients with Medicaid had more emergency department visits, on average, than patients without Medicaid.

DISCUSSION

Attaining health equity requires evidence-based strategies to correct and prevent disparities in health care access.^2-4 However, the concept of access to care is multifaceted—here, we rely on a definition of access broken down across 5 dimensions (affordability, availability, accessibility, accommodation, and acceptability).¹¹ Additionally, disparities in health care are influenced by multiple economic, social, and environmental factors.^3,4 The relationship between disparities in health care access and patient outcomes is complex; thus, we conducted a systematic literature review to better understand disparities in physician specialist access across rheumatology, dermatology, and gastroenterology in the US.

Importantly, we identified a paucity of literature on disparities in specialty care for prevalent conditions that often disproportionally affect underserved communities (eg, atopic dermatitis).⁴¹ Also, little evidence was identified in gastroenterology, hindering detailed analysis for this field. Although disparities in specialist access were inconsistently studied across the evaluated specialties, the existing evidence highlights factors that contribute to inequitable access to care for certain US populations. Factors that were well documented in the literature as influencing disparities in access to rheumatologists and dermatologists included rural residence, insurance type (primarily Medicaid), Black or Hispanic race and ethnicity, and low specialist density in a region. Few studies evaluated the clinical and economic consequences of these disparities in specialist access, but related outcomes included higher disease severity, higher hospital admission and readmission rates, and higher numbers of emergency department visits.

Many of the factors that contribute to health care disparities, such as rural residence and low specialist density, may be closely related. For example, according to the US National Rural Health Association, there are only 30 specialists (any medical specialty) per 100,000 individuals in rural areas vs 263 specialists per 100,000 individuals in urban areas.⁴² Insurance type and race and ethnicity are also factors that may be closely intertwined. In 2022, 39% of Black and 34% of Hispanic individuals aged 0 to 64 years were covered by Medicaid or other public insurance compared with 20% of White individuals.⁴³ Both public insurance and Black or Hispanic race and ethnicity are associated with low access to specialists and worse health outcomes.^5,6,25,26,37 Overall, these findings highlight the complex nature of health care disparities and the intricate challenges of addressing disparities in access.

Notably, our systematic review revealed several gaps in the research on health care disparities that need to be addressed. First, there is relatively limited evidence regarding disparities in access to specialists in rheumatology, dermatology, and—particularly—gastroenterology (an important research gap) in the US, and evidence on acceptance and accommodation is especially lacking. Thus, there is a need for scientific and clinical leaders to bridge this evidence gap and to provide specialists with potential solutions and interventions. For instance, studies evaluating the acceptance of racially or ethnically diverse patients among physicians of various racial or ethnic backgrounds, and associated outcomes, may provide potential opportunities to improve community trust and downstream care for patients belonging to underrepresented racial or ethnic groups.^44,45 We also identified a lack of longitudinal evidence on the impact that disparities in specialist access have on clinical or economic outcomes. This could be due to a lack of longitudinal data on study outcomes or due to publication bias. Therefore, further research evaluating the relationship between health care disparities and long-term patient outcomes is warranted and may provide an opportunity to increase education and awareness among physicians. Lastly, because data reporting varies across studies, the results of many studies are not generalizable. Thus, there is a need to identify, assess, and leverage data sources with SDOH variables⁴⁶ for future studies addressing disparities in specialist access.

Evidence-Based Recommendations

To overcome barriers in specialist access, many existing disparities must be addressed. We identified numerous studies that offered potential solutions to work toward this goal and compiled evidence-based recommendations addressing each of the 5 A’s of access. To improve affordability, payers, providers, and researchers should focus on minimizing structural barriers, such as barriers in specialist access, high costs of care, and a lack of optimal insurance.^30,38,47 For instance, Jew et al³⁸ described a need to reduce the barrier of prior authorization, which could be done using strategies such as providing visit reimbursements retroactively when prior authorization is approved at a later stage; this would ensure patients are seen by an appropriate provider in the shortest amount of time. To improve availability, several studies suggested using a multidisciplinary approach to reduce the burden on the provider and increase the practice’s capacity, thereby maximizing the role of other health care professionals (eg, physician assistants, nurses, pharmacists).^7,32,33 Recommendations for enhancing accessibility included promoting telemedicine, providing travel support, and strengthening incentives for the recruitment of specialists to US regions where specialists are lacking.^25,32,35,47 Additionally, to improve acceptability, there are opportunities to increase health literacy via patient support programs, public awareness campaigns, and educational materials.^30,31,34,48 Lastly, for accommodation, partnerships with the health care community can better meet patient needs.^34,49

To achieve health equity, it is critical to identify existing disparities in health care access and to develop evidence-based strategies to overcome these barriers. Science and public health leaders should continue asking key questions, including the following: What are the key focus areas in health care disparities? Who has the responsibility to minimize health care disparities—health care providers, payers, and/or policy makers? How do we develop and implement long-term solutions to alleviate health care disparities? Collective efforts to answer these questions will help eliminate health care disparities and ensure that all people can attain the highest possible level of health.^3,4,50

Limitations and Strengths

Although we were able to identify factors associated with low access to specialists, our study may be limited by general data collection challenges for health disparity studies; key SDOH may not be commonly collected (eg, income, education, and occupation of patients), and data reporting varies across studies. Of note, although we used the 5 A’s of access as a systematic framework for this review, studies may use different criteria to characterize disparities in access. Also, because most studies tend to examine individual factors, the results of the studies included in our literature review may underestimate disparities affecting individuals belonging to multiple disadvantaged groups. Additionally, because there were few eligible studies, our evidence synthesis did not estimate effect size and did not cover all immunological diseases in rheumatology, dermatology, and gastroenterology. Similarly, due to limited extant literature, evidence-based recommendations were not systematically reviewed, and no evidence grading was conducted.

To our knowledge, this is the first systematic review to comprehensively evaluate disparities in access to specialists within rheumatology, dermatology, and gastroenterology. Notably, the results of this review provide (1) deeper insight into gaps that must be filled through future research and (2) recommendations to minimize disparities in specialist access.

CONCLUSIONS

Mitigating disparities in specialist care access is key to achieving health equity. In this systematic literature review, we identified key factors that lowered access to specialists in the fields of rheumatology and dermatology, including rural residence, insurance type (primarily Medicaid), Black or Hispanic race and ethnicity, and low specialist density. Furthermore, evidence-based solutions to mitigate existing health care disparities and barriers to specialist access are provided, including recommendations for all 5 A’s of access (affordability, availability, accessibility, accommodation, and acceptability). Because limited evidence was identified in gastroenterology, conclusions in this field cannot be inferred. Also, because disparities in specialist access are inconsistently studied, future studies are needed to further evaluate the impact of these disparities on clinical and economic outcomes in rheumatology, dermatology, and gastroenterology.

Acknowledgments

The authors thank Weyinmi Nuabor, MPH, and Alisha Krumbach, PharmD, of RTI Health Solutions for their assistance with literature screening and data analysis. The authors also thank Lacey Lopez, PhD, and Cassondra Saande, PhD, of RTI Health Solutions for medical writing assistance.

Author Affiliations: Association of Women in Rheumatology (GCW), New York, NY; Howard University (GAO), Washington, DC; Temple University Hospital (ACE), Philadelphia, PA; AbbVie, Inc, North Chicago, IL (DJL, OO, MM), and Buckinghamshire, United Kingdom (KO); RTI Health Solutions, Durham, NC (SK), Didsbury, United Kingdom (JC), and Ann Arbor, MI (CC-M).

Source of Funding: AbbVie provided the financial support for this study. RTI Health Solutions, an independent nonprofit research organization, received funding under a research contract with AbbVie to conduct this study and provide publication support in the form of manuscript writing, styling, and submission.

Author Disclosures: Dr Wright is a board member of the Association of Women in Rheumatology; has consulted for AbbVie, Bristol Myers Squibb, and Janssen, and has received honoraria and lecture fees from AbbVie, AstraZeneca, Bristol Myers Squibb, Eli Lilly and Company, Novartis, and Pfizer. Dr Okoye is a board member of the Hidradenitis Suppurativa Foundation; has consulted for Incyte, Novartis, Sandoz, and UCB; and has received grants from Janssen. Dr Ehrlich has consulted for AbbVie, Bristol Myers Squibb, and Eli Lilly and Company and has received lecture fees from AbbVie and Eli Lilly and Company. Dr Lorimier, Dr Ovbiosa, and Dr Mittal are employees of AbbVie and shareholders of AbbVie stock, and Dr Mittal has attended the Academy of Managed Care Pharmacy Annual Meeting. Dr Onishchenko was employed at AbbVie throughout this study and has been a shareholder of AbbVie stock. At the time of this study, Ms Khan, Ms Costello, and Ms Copley-Merriman were full-time employees of RTI Health Solutions, an independent nonprofit research organization, which was retained by AbbVie to conduct the research that is the subject of this manuscript.

Authorship Information: Concept and design (DJL, C-CM, KO, OO, MM); acquisition of data (SK, JC, OO, MM); analysis and interpretation of data (GCW, GAO, ACE, DJL, SK, JC, CC-M, KO, MM); drafting of the manuscript (GCW, GAO, ACE, DJL, SK, JC, CC-M, KO, MM); critical revision of the manuscript for important intellectual content (GCW, GAO, ACE, DJL, SK, JC, KO, OO, MM); obtaining funding (DJL, MM); administrative, technical, or logistic support (DJL); and supervision (GAO, ACE, DJL, MM).

Address Correspondence to: Manish Mittal, PhD, AbbVie Inc, Dept GMH1, Bldg ABV1-4SE-113-05, 26525 N Riverwoods Blvd, Mettawa, IL 60045. Email: manish.mittal@abbvie.com.

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