US Health Care Disparities in Immunology Biologics Access: A Systematic Review

ABSTRACT

Objectives: Biologics have substantially improved health outcomes for patients with immunologic conditions. However, not all patients have equitable access to these important medications. Accordingly, we conducted a systematic review to understand US health care disparities in biologics access and associated clinical and economic outcomes, including health care resource use, across immunology (ie, rheumatology, gastroenterology, and dermatology).

Study Design: Systematic literature review.

Methods: We searched PubMed, Web of Science, and Embase databases for studies published between 2017 and 2023 focused on access to biologic treatments for US adult patients (≥ 18 years) diagnosed with immunologic conditions.

Results: Across the 21 studies included in this systematic review, disparities in biologics access were inconsistently studied, and only 8 studies (38%) evaluated clinical or economic outcomes of low biologics access. The factors most frequently associated with disparities in access to biologics included insurance type; Black, Hispanic, or Asian race or ethnicity; high out-of-pocket costs; and insurance prior authorization requirements. These disparities were associated with worse clinical and economic outcomes, including higher hospital admission and readmission, higher number of emergency department visits, and treatment delays. However, some studies found no association between some of these disparities and access to biologics, highlighting the complexity of the issue.

Conclusions: We identified key factors that influence disparities in biologics access within immunology across the US, which were associated with worse clinical and economic outcomes. We highlight potential solutions to minimize disparities in biologics access and the need for more in-depth research to address these disparities.

Am J Manag Care. 2025;31(8):414-420. https://doi.org/10.37765/ajmc.2025.89774

Takeaway Points

It is critical to ensure equitable access to biologics for patients with immunologic conditions. In this systematic literature review, we found the following:

• Evidence is lacking on disparities in biologics access, with inconsistent evidence regarding the effects of such disparities on clinical or economic outcomes.
• Access was influenced by factors such as insurance type and race/ethnicity; however, these disparities are inconsistently studied across immunology, and further studies are needed to assess their impact on patient outcomes.
• Potential solutions to improve US biologics access include reducing financial barriers, improving health literacy, increasing stakeholder awareness, and developing partnerships with the health care community.

Over the past 2 decades, novel biologics have provided effective and targeted treatment of immunological diseases, including rheumatoid arthritis (RA), psoriatic arthritis (PsA), ankylosing spondylitis (AS), psoriasis, atopic dermatitis (AD), and inflammatory bowel disease (IBD).^1,2 Biologics have led to significantly improved health outcomes, including better symptom management and slower disease progression.^3,4 However, the cumulative impact of delays between symptom onset and clinical assessment,^5,6 cost concerns,⁷ time spent receiving nonbiologic therapies,⁸ and the need for insurance prior authorizations^9-12 may impede biologics initiation. Furthermore, not all patients with immunologic conditions have equitable treatment access.¹³

Health care access, including access to treatments for immunological disease, is substantially impacted by social, political, and economic factors in the US.¹⁴ Many historically underserved populations, including racially and ethnically diverse groups and individuals with lower socioeconomic status (SES), experience disparities in treatment access.^15,16 In addition, the complexity of biologics research and development, manufacturing, and distribution drives high drug pricing.^17,18 Policies such as prior authorization requirements and co-pay accumulators and maximizers—in which manufacturers’ assistance with drug costs does not reduce patients’ out-of-pocket (OOP) costs—also hamper biologics access.^13,19 Furthermore, biologics are specialty drugs that may be available only in specialty pharmacies or may require administration at infusion centers. These barriers limit timely access to much-needed medications and may lead to worse clinical outcomes, including disease progression, increased disability, and reduced health-related quality of life.^9,20

Biologics have demonstrated clinical and economic value, resulting in improved outcomes for patients with immune conditions; therefore, it is critical to ensure access to these drugs. A comprehensive review of the literature on these disparities within the field of immunology is an essential first step in assessing available evidence to better understand disparities in biologics access and to work toward equitable access to these medications. Accordingly, we conducted this systematic literature review to understand US health care disparities in biologics access and associated clinical and economic outcomes across immunology (ie, rheumatology, gastroenterology, and dermatology). Herein, we describe gaps in existing evidence and potential strategies to address these disparities in access to biologics.

METHODS

Study Design

We systematically reviewed the published evidence on disparities in access to biologics—such as biologic disease-modifying antirheumatic drugs (bDMARDs)—and their associated outcomes across immunology. We searched PubMed, Web of Science, and Embase databases on February 17, 2023, to identify relevant articles published from January 1, 2017, through September 30, 2022, and conference abstracts (Embase only) published from February 17, 2021, through February 17, 2023. These time frames were selected to identify articles and abstracts reflecting the current disparities in access to biologics. Search strategies, including therapeutic areas and interventions, are in eAppendix Tables 1 to 3 (eAppendix available at ajmc.com).

Eligible studies assessed biologic agents used in immunology (ie, rheumatology, dermatology, and gastroenterology) for US adult patients (≥ 18 years) in the outpatient or inpatient setting diagnosed with immunologic conditions (RA, PsA, AS, psoriasis, AD, and IBD). We evaluated disparities in access to biologics across immunology and associated clinical and economic outcomes, including health care resource use (eg, hospitalization, emergency department [ED] visits, medication use). eAppendix Table 4 presents the study eligibility criteria.

A single researcher (A.K.) screened publications on 2 levels: level 1 screening of titles/abstracts and level 2 screening of full-text articles. A second reviewer (S.K.) checked the records at each screening level, and a third reviewer (C.C.-M.) reconciled any discrepancies. Additional relevant articles were identified via bibliography review of included publications. Data from included studies were synthesized and analyzed thematically.

RESULTS

We identified 1363 unique publications through database searches (Figure 1), of which 1309 were excluded during level 1 screening and 40 were excluded during level 2 screening, with 14 publications remaining. The primary reasons for exclusion were population and outcomes not meeting the eligibility criteria. Another 7 publications were identified via bibliography review of included publications, resulting in 21 total included publications (20 full-text articles and 1 conference abstract). The predominant data sources were real-world administrative claims databases (n = 6; 29%) or literature reviews (n = 4; 19%).

Common Disparities in Biologics Access

Disparities in biologics access were inconsistently studied across immunology. Of the 21 included studies, most articles focused on dermatology (n = 10; 48%), followed by rheumatology (n = 7; 33%) and gastroenterology (n = 4; 19%).

Across studies, the top factors associated with disparities affecting biologics access included insurance type; Black, Hispanic, or Asian race and ethnicity; and high OOP costs (Figure 2). Other factors reported by 3 or fewer studies included lower SES (including lower education and income), living in a rural area, being female, living in the Midwest, having skin of color (differentiated from race), need for prior authorization, long prior authorization wait times, being older, and having a general physician visit rather than specialist visit. All studies are listed in the Table^6,9,10,21-37 and are summarized in eAppendix Table 5.

Insurance Type

Eight studies (rheumatology [n = 5],^21-25 dermatology [n = 2],^26,27 and gastroenterology [n = 1]²⁸) reported that insurance type was associated with low biologics access. Several of these studies reported that patients with commercial insurance were more likely than patients with public insurance (Medicare or Medicaid) to receive biologics, whereas others reported the opposite, resulting in inconsistent findings. For example, in a study evaluating claims data, Jin et al²² identified that patients with commercial insurance were 87% more likely to initiate RA treatment with bDMARDs than were patients with Medicaid. Similarly, in a claims study of patients with RA by Kan et al,²⁵ having commercial insurance was significantly associated with biologics adherence (ie, filling or administration of biologics within 3 months) compared with Medicare insurance. In contrast, in a study that analyzed visits recorded in the National Ambulatory Medical Care Survey, Gaitonde et al²⁴ found that patients with RA who had Medicare insurance had higher odds of receiving bDMARDs vs patients with commercial insurance. Also, a retrospective surveillance study by Axelrad et al²⁸ reported that patients with IBD who had Medicaid insurance had higher rates of biologic infusions than did patients with other insurance types.

Black, Hispanic, or Asian Race and Ethnicity

Eight studies (rheumatology [n = 2],^22,23 dermatology [n = 4],^6,27,29,30 and gastroenterology [n = 2]^31,32) reported that race and ethnicity were associated with low biologics access. Specifically, many studies identified that patients with Black, Hispanic, or Asian race and ethnicity were less likely to receive biologics than White patients. In a claims study among patients with Medicaid insurance, Jin et al²² found that Black patients had 30% to 40% lower odds of initiating bDMARDs for RA treatment vs non-Hispanic White patients. Likewise, in several dermatological studies, Black patients were less likely to receive or use biologics for psoriasis treatment compared with White patients.^6,27,29,30 In similar studies of psoriasis management, use of biologics was lower among patients from other underrepresented groups (defined as Asian, American Indian, Alaskan Indian, other Pacific Islander, and unknown) than among White patients.^29,30 However, 4 studies did not find associations between health disparities and barriers to biologics access, and 2 studies found increased biologics access in patients belonging to underrepresented racial or ethnic groups compared with White patients.^{10,24,26,28,32,38} For example, Axelrad et al²⁸ found that in Medicaid patients with IBD, there was no significant association with requiring biologic infusions in Black or Hispanic patients compared with White patients, and Gaitonde et al²⁸ reported that race and ethnicity were not associated with DMARD or bDMARD use in patients with rheumatoid arthritis. Gonzalez and Fleischer³⁰ found that in patients with psoriasis, there was an increased likelihood of biologic use in Latino patients compared with non-Latino patients.

High OOP Costs and Prior Authorization

Five studies (rheumatology [n = 2]^21,33 and dermatology [n = 3]^9,10,29) reported that high OOP costs were associated with low biologics access. Of these, 2 studies in dermatology^9,10 also reported prior authorization as a key factor associated with low biologics access. In a rheumatological study, the authors reported that the odds of RA treatment adherence were highest for patients with no OOP costs per fill.³³ To underscore this point, more than 70% of participants in a dermatological survey study by Yadav et al²⁹ reported that high OOP costs were among the largest barriers to seeking treatment for psoriasis. Also, in dermatological studies, many patients experienced a barrier due to the need for prior authorizations, which can result in delays to treatment initiation, a high administrative burden for providers, and increased OOP costs for patients.^9,10,19 Notably, in a prospective cohort study by Jew et al,⁹ 100% of prior authorizations for biologics were initially denied for patients with dermatological conditions, although this result was based on only 6 records.

Common Outcomes of Disparities in Access to Biologics

Of the 21 included studies, only 8 (38%) evaluated clinical or economic outcomes of low biologics access (Figure 2). These outcomes were inconsistently reported across immunology (5% [n = 1] in rheumatology,³³ 19% [n = 4] in dermatology,^9,10,29,34 and 14% [n = 3] in gastroenterology^28,31). Five studies (24%) were longitudinal in design (eg, prospective observational, retrospective pharmacy claims, medical record review studies), 1 study (5%) evaluated clinical outcomes based on area of residence, and 2 literature review studies (10%) evaluated only clinical outcomes. Among studies, the most reported outcomes of low biologics access were higher hospital admission and readmission rates, higher number of ED visits, and treatment delay (Figure 3). Other outcomes reported by 1 study each included low biologic adherence rates, greater steroid use, and diagnosis delay. The Table lists all studies and eAppendix Table 5 summarizes their reported outcomes.

Among the top reported outcomes, a dermatology-focused literature review by Yadav et al²⁹ reported that Black, Hispanic, Asian, or multiracial (other than White) patients were more likely than White patients to be hospitalized for psoriasis. These authors noted that increased hospitalization rates may be indicative of severe or inadequately managed psoriasis. Additionally, in a retrospective gastroenterological study, Axelrad et al²⁸ found that patients with Medicaid insurance had higher hospital and ED visit rates than patients with other insurance types. Lastly, in 2 dermatology studies, prior authorization resulted in delayed access to treatment.^9,10 Importantly, Vazquez et al¹⁰ found higher rates of clinical deterioration in patients who experienced delays to biologics insurance approvals.

DISCUSSION

This systematic review provides a deeper understanding of disparities in biologics access across immunology, focusing on the fields of rheumatology, dermatology, and gastroenterology. Although we found that disparities in biologics access and their associated outcomes were inconsistently studied across immunology, the existing literature reveals factors that may impact access to these therapies among certain patient populations with immunologic conditions. The most frequently reported factors that influenced biologics access included insurance type; Black, Hispanic, or Asian race and ethnicity; higher OOP costs; and prior authorization. Common outcomes of low biologics access included higher hospital admission and readmission rates, higher number of ED visits, and treatment delays. However, we also identified articles that found no association between these identified disparities and access to biologics, and few articles reported clinical or economic outcomes. Overall, health care disparities in biologics access and their associated outcomes remain a complex issue that requires further study.

Although biologics may be high value and provide clinically significant benefits to patients, there is considerable concern regarding the fiscal burden they entail. As such, their cost is an important topic of health disparities studies.¹³ Results of our systematic review, comprising mostly studies on affordability, indicate that insurance type, prior authorization, and high OOP costs were key factors associated with disparities in biologics access across immunology.^21-28 Notably, different insurers may have varying coverage and different requirements surrounding co-payments, coinsurance, and prior authorization, all of which may impact OOP costs and access to specialty drugs such as biologics.¹⁹ For example, Ogdie et al²³ reported that the percentage of bDMARD prescriptions was lower for patients with Medicare or Medicaid insurance than for those with commercial insurance. Also, a study by Jew et al⁹ reported that the percentage of initial prior authorization denials was highest for biologics vs all other medication classes or diagnostic orders. However, this finding should be interpreted with caution, as prior authorizations could be denied due to high costs or if prescribing biologic therapies was not appropriate for a given indication. Additionally, Mukherjee and Kamal²¹ found that bDMARDs had the highest annual OOP and total expenditures vs other classes of RA medications (ie, conventional DMARDs, nonsteroidal anti-inflammatory drugs, narcotic analgesics, and corticosteroids), and the authors hypothesized that increasing OOP expenditures may negatively impact medication adherence. Indeed, the complexities of biologics development, together with the complexities of the US health care system, impact their affordability for patients and exacerbate disparities in access. The high price of biologics, which can drive payers to erect barriers to access, also remains a concern. Therefore, increasing the affordability of biologics is key to mitigating these disparities.

Although the studies in this review highlight factors contributing to disparities in biologics access, most studies did not determine why certain groups were more likely to experience these disparities. It is well established that inequities in treatment access likely involve a multitude of factors.³¹ For example, certain groups of people may be underrepresented in clinical trials for biologic therapies and/or lack familiarity with the treatment option, leading to suboptimal disease management in these patient populations.²⁹ Many of the factors resulting in low biologics access—such as race and ethnicity, SES, and insurance type—may also be interrelated. For instance, Yadav et al²⁹ found that the perceived impact of the high costs of care was more pronounced for Black patients compared with White patients. Additionally, in a study evaluating racial differences in treatment for PsA and AS by insurance coverage, Ogdie et al²³ reported that the percentage of bDMARD prescriptions was lower for Black patients with Medicaid insurance compared with White patients with Medicaid insurance. Taken together, these findings highlight the complex interplay between numerous factors contributing to disparities in biologics access and underscore the need to develop strategies to overcome these disparities.

Importantly, numerous studies in our systematic review offered insights on potential solutions to disparities in biologics access. To improve the affordability of prescription medications, Mukherjee and Kamal²¹ noted that clinicians play an important role in identifying patients who are experiencing financial hardship; providing these patients with information on sources of low-cost medications and enrolling them in financial assistance programs may reduce some of their financial barriers.^21,33 Additionally, developing biosimilars and expanding drug formularies may limit high OOP costs for patients and lower costs for health care systems.^9,27,39

To improve availability, providing case management may assist patients in navigating the health care system and reduce specialist wait times for patients with more severe disease.²⁸ Accessibility may be enhanced by providing patient awareness campaigns using multiple outreach channels (eg, schools, community centers). Patient support programs have helped to improve both availability and access to biologic treatments by providing financial support to patients. These programs have assisted with treatment regimen management and have been associated with reduced health care costs and prescription abandonment.^40-43 Therefore, patient support programs not only provide accessibility to patients but also have the potential to improve long-term patient outcomes. Further recommendations for improving acceptability include increasing health literacy via public awareness campaigns and educational materials, and conducting additional studies with larger populations of vulnerable and minority group patients to address the poor representation of these patients.²⁹ The FDA acknowledges the education of both patients and clinicians as a key component of improving biologics accessibility.⁴⁴ Additionally, product development and public-private partnerships have been frequently implemented within the health care sector to provide access to treatment services, and multistakeholder collaborations should be considered as a strategy for enhancing biologics treatment accessibility.^45,46

Although several valuable solutions to disparities in biologics access have been proposed, there remains a lack of evidence on biologics access. We also identified limited evidence on clinical or economic outcomes related to disparities in biologics access and a lack of patient-reported data in this space. Thus, there are opportunities to conduct longitudinal observational studies to evaluate the clinical or economic outcomes of these disparities. Patient-focused research is also needed to provide a better understanding of patients’ experiences with disparities in biologics access. Importantly, addressing gaps in the existing literature will enhance our insights on possible solutions to disparities in access and help drive scientific leadership to work toward achieving equitable access to biologics across diverse populations.

Limitations

Results of this systematic review are subject to the limitations of data collection inherent to health disparities studies. First, key elements of SES data, including income, education, and patient occupation, are not commonly collected. Additionally, patients may be influenced by more than 1 factor related to health disparities, but many studies focus on a particular underrepresented group, potentially underestimating health disparity risk for a particular patient. Likewise, diseases may be underdiagnosed, and treatment patterns may be underreported for some groups of people, resulting in the underestimation of some disparities.⁶ Furthermore, this review found no evidence of US health care disparities in access to biologics for pan-immunology overall. Many of the included studies reported contrasting findings, which may be explained in part by the fact that many studies were single-center or, in some cases, single-clinic evaluations. Lastly, this review evaluated studies published in English and conducted within the US, and findings presented herein may not be representative of disparities in biologics access globally. Importantly, this is the first comprehensive review of this topic, and along with providing an analysis of existing literature gaps, this study provides recommendations to minimize these disparities in US health care. Due to the paucity of literature, reported recommendations were not systematically reviewed and evidence grading was not conducted. Further research is needed to better understand the reasons behind these disparities, particularly in the context of the US health care system, to develop recommendations to improve access and health outcomes in the US. Additionally, future studies are warranted to understand how health care disparities relate to specific biologic therapies for immune conditions.

CONCLUSIONS

In this systematic review, we identified key factors that influenced biologics access across US immunology (ie, rheumatology, dermatology, and gastroenterology), including insurance type; Black, Hispanic, or Asian race and ethnicity; higher OOP costs; and prior authorization requirements. These disparities were associated with worse clinical outcomes, such as higher hospital admission and readmission rates, higher number of ED visits, and treatment delays. We also identified and summarized potential solutions to minimize disparities in biologics access. Although our results provide a deeper understanding of disparities in biologics access, these disparities are inconsistently studied across immunology, and further studies are needed to assess their impact on patient outcomes.

Acknowledgments

The authors thank Cassondra Saande, PhD; Lacey Lopez, PhD; and Taylor Tibbs, PhD, of RTI Health Solutions for their 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, Research Triangle Park, NC (SK), and Ann Arbor, MI (AK, 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, AstraZeneca, Bristol Myers Squibb, Eli Lilly, GSK, Janssen, Novartis, Pfizer, and UCB; has received honoraria from AbbVie, AstraZeneca, Bristol Myers Squibb, Eli Lilly, GSK, Janssen, Novartis, Pfizer, and UCB. 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, Pfizer, Bristol Myers Squibb, Eli Lilly, Nestle/Aimmune, and Janssen and has received lecture fees from AbbVie, Eli Lilly, and Bristol Myers Squibb. 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 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, Dr Krumbach, 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, SK, CC-M, KO, OO, MM); acquisition of data (SK, AK, CC-M, OO, MM); analysis and interpretation of data (GCW, GAO, ACE, DJL, SK, AK, CC-M, KO, MM); drafting of the manuscript (GCW, ACE, DJL, SK, AK, CC-M, KO, OO, MM); critical revision of the manuscript for important intellectual content (GCW, GAO, ACE, DJL, SK, AK, CC-M, KO, OO, MM); obtaining funding (DJL, MM); administrative, technical, or logistic support (DJL, AK); 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.

REFERENCES

1. Nash P, Kerschbaumer A, Dörner T, et al. Points to consider for the treatment of immune-mediated inflammatory diseases with Janus kinase inhibitors: a consensus statement. Ann Rheum Dis. 2021;80(1):71-87. doi:10.1136/annrheumdis-2020-218398

2. Benjamin O, Goyal A, Lappin SL. Disease-modifying antirheumatic drugs (DMARD). In: StatPearls. StatPearls Publishing; 2023. Accessed February 20, 2024. https://www.ncbi.nlm.nih.gov/books/NBK507863/

3. Hyndman IJ. Rheumatoid arthritis: past, present and future approaches to treating the disease. Int J Rheum Dis. 2017;20(4):417-419. doi:10.1111/1756-185X.12823

4. Upchurch KS, Kay J. Evolution of treatment for rheumatoid arthritis. Rheumatology (Oxford). 2012;51(suppl 6):vi28-36. doi:10.1093/rheumatology/kes278

5. Kumar K, Daley E, Carruthers DM, et al. Delay in presentation to primary care physicians is the main reason why patients with rheumatoid arthritis are seen late by rheumatologists. Rheumatology (Oxford). 2007;46(9):1438-1440. doi:10.1093/rheumatology/kem130

6. Heath CR, Usatine RP. Psoriasis. J Fam Pract. 2021;70(6):303. doi:10.12788/jfp.0241

7. Rubin DT, Feld LD, Goeppinger SR, et al. The Crohn’s and Colitis Foundation of America survey of inflammatory bowel disease patient health care access. Inflamm Bowel Dis. 2017;23(2):224-232. doi:10.1097/MIB.0000000000000994

8. Kim G, Barner JC, Rascati K, Richards K. Examining time to initiation of biologic disease-modifying antirheumatic drugs and medication adherence and persistence among Texas Medicaid recipients with rheumatoid arthritis. Clin Ther. 2016;38(3):646-654. doi:10.1016/j.clinthera.2016.01.022

9. Jew OS, Okawa J, Barbieri JS, McCaffrey J, Hayward E, Werth VP. Evaluating the effect of prior authorizations in patients with complex dermatologic conditions. J Am Acad Dermatol. 2020;83(6):1674-1680. doi:10.1016/j.jaad.2020.06.998

10. Vazquez T, Forouzandeh M, Lin D, et al. Insurance delays in the approval of biologic medications for patients with psoriasis and psoriatic arthritis. Arch Dermatol Res. 2023;315(5):1401-1403. doi:10.1007/s00403-022-02457-6

11. Constant BD, de Zoeten EF, Stahl MG, et al. Delays related to prior authorization in inflammatory bowel disease. Pediatrics. 2022;149(3):e2021052501. doi:10.1542/peds.2021-052501

12. Sehanobish E, Ye K, Imam K, et al. Elaborate biologic approval process delays care of patients with moderate-to-severe asthma. J Allergy Clin Immunol Glob. 2023;2(2):100076. doi:10.1016/j.jacig.2022.10.007

13. Sariahmed K, Kurian J, Singh AK, et al. Social, political, and economic determinants of access to biologics: a scoping review of structural determinants in the clinical disparities literature. Res Social Adm Pharm. 2022;18(12):4038-4047. doi:10.1016/j.sapharm.2022.07.047

14. Evans MK. Health equity - are we finally on the edge of a new frontier? N Engl J Med. 2020;383(11):997-999. doi:10.1056/NEJMp2005944

15. What is health equity? CDC. Updated July 1, 2022. Accessed September 14, 2023. https://web.archive.org/web/20230913184819/https://www.cdc.gov/healthequity/whatis/index.html

16. Social determinants of health. CDC. Updated December 8, 2022. Accessed February 21, 2024.
https://web.archive.org/web/20240221011755/https://www.cdc.gov/about/sdoh/index.html

17. Kvien TK, Patel K, Strand V. The cost savings of biosimilars can help increase patient access and lift the financial burden of health care systems. Semin Arthritis Rheum. 2022;52:151939. doi:10.1016/j.semarthrit.2021.11.009

18. Makurvet FD. Biologics vs. small molecules: drug costs and patient access. Med Drug Discov. 2021;9:100075. doi:10.1016/j.medidd.2020.100075

19. Ismail WW, Witry MJ, Urmie JM. The association between cost sharing, prior authorization, and specialty drug utilization: a systematic review. J Manag Care Spec Pharm. 2023;29(5):449-463. doi:10.18553/jmcp.2023.29.5.449

20. Favier G, Gladman DD, Merola JF, Armstrong AW, Boehncke WH, Helliwell PS. Benchmarking care in psoriatic arthritis — the QUANTUM report: a report from the GRAPPA 2016 Annual Meeting. J Rheumatol. 2017;44(5):674-678. doi:10.3899/jrheum.170142

21. Mukherjee K, Kamal KM. Sociodemographic determinants of out-of-pocket expenditures for patients using prescription drugs for rheumatoid arthritis. Am Health Drug Benefits. 2017;10(1):7-15.

22. Jin Y, Desai RJ, Liu J, Choi NK, Kim SC. Factors associated with initial or subsequent choice of biologic disease-modifying antirheumatic drugs for treatment of rheumatoid arthritis. Arthritis Res Ther. 2017;19(1):159. doi:10.1186/s13075-017-1366-1

23. Ogdie A, Matthias W, Thielen RJ, Chin D, Saffore CD. Racial differences in prevalence and treatment for psoriatic arthritis and ankylosing spondylitis by insurance coverage in the USA. Rheumatol Ther. 2021;8(4):1725-1739. doi:10.1007/s40744-021-00370-4

24. Gaitonde P, Bozzi LM, Shaya FT. Factors associated with use of disease modifying agents for rheumatoid arthritis in the National Hospital and Ambulatory Medical Care Survey. Semin Arthritis Rheum. 2018;47(5):649-653. doi:10.1016/j.semarthrit.2017.10.011

25. Kan HJ, Dyagilev K, Schulam P, et al. Factors associated with physicians’ prescriptions for rheumatoid arthritis drugs not filled by patients. Arthritis Res Ther. 2018;20(1):79. doi:10.1186/s13075-018-1580-5

26. Gonzalez T, Fleischer AB, Jr. Increased biologic utilization in Latino patients with psoriasis. J Dermatolog Treat. 2022;33(2):965-968. doi:10.1080/09546634.2020.1793889

27. Aleshaki JS, Cardwell LA, Muse ME, Feldman SR. Adherence and resource use among psoriasis patients treated with biologics. Expert Rev Pharmacoecon Outcomes Res. 2018;18(6):609-617. doi:10.1080/14737167.2018.1512408

28. Axelrad JE, Sharma R, Laszkowska M, Packey C, Rosenberg R, Lebwohl B. Increased healthcare utilization by patients with inflammatory bowel disease covered by Medicaid at a tertiary care center. Inflamm Bowel Dis. 2019;25(10):1711-1717. doi:10.1093/ibd/izz060

29. Yadav G, Yeung J, Miller-Monthrope Y, et al. Unmet need in people with psoriasis and skin of color in Canada and the United States. Dermatol Ther (Heidelb). 2022;12(11):2401-2413. doi:10.1007/s13555-022-00811-0

30. Hodges WT, Bhat T, Raval NS, et al. Biologics utilization for psoriasis is lower in Black compared with White patients. Br J Dermatol. 2021;185(1):207-209. doi:10.1111/bjd.19876

31. Barnes EL, Loftus EV Jr, Kappelman MD. Effects of race and ethnicity on diagnosis and management of inflammatory bowel diseases. Gastroenterology. 2021;160(3):677-689. doi:10.1053/j.gastro.2020.08.064

32. Kochar B, Barnes EL, Herfarth HH, et al. Asians have more perianal Crohn disease and ocular manifestations compared with White Americans. Inflamm Intest Dis. 2018;2(3):147-153. doi:10.1159/000484347

33. Berger N, Peter M, DeClercq J, Choi L, Zuckerman AD. Rheumatoid arthritis medication adherence in a health system specialty pharmacy. Am J Manag Care. 2020;26(12):e380-e387. doi:10.37765/ajmc.2020.88544

34. Nguyen KB, Read C, Wu KK, Armstrong AW. Where you live matters: regional differences in health care resource use for psoriasis in the United States. J Am Acad Dermatol. 2020;82(6):1360-1367. doi:10.1016/j.jaad.2019.10.014

35. Peterman NJ, Vashi A, Govan D, et al. Evaluation of access disparities to biologic disease-modifying antirheumatic drugs in rural and urban communities. Cureus. 2022;14(6):e26448. doi:10.7759/cureus.26448

36. Cheraghlou S, Cohen JM. Early adoption of dupilumab in the Medicare population in 2017. Yale J Biol Med. 2020;93(5):675-677.

37. Feng H, Cohen JM, Neimann AL. Access to injectable biologic medications by Medicare beneficiaries: geographic distribution of US dermatologist prescribers. J Dermatolog Treat. 2019;30(3):237-239. doi:10.1080/09546634.2018.1508819

38. Barnes EL, Bauer CM, Sandler RS, Kappelman MD, Long MD. Black and White patients with inflammatory bowel disease show similar biologic use patterns with Medicaid insurance. Inflamm Bowel Dis. 2021;27(3):364-370. doi:10.1093/ibd/izaa090

39.Inflation Reduction Act research series: Medicare drug price negotiation program: understanding development and trends in utilization and spending for the selected drugs. Office of the Assistant Secretary for Planning and Evaluation research report. December 14, 2023. Accessed April 11, 2024. https://aspe.hhs.gov/sites/default/files/documents/4bf549a55308c3aadc74b34abcb7a1d1/ira-drug-negotiation-report.pdf

40. Brixner D, Mittal M, Rubin DT, et al. Participation in an innovative patient support program reduces prescription abandonment for adalimumab-treated patients in a commercial population. Patient Prefer Adherence. 2019;13:1545-1556. doi:10.2147/PPA.S215037

41. Brixner D, Rubin DT, Mease P, et al. Patient support program increased medication adherence with lower total health care costs despite increased drug spending. J Manag Care Spec Pharm. 2019;25(7):770-779. doi:10.18553/jmcp.2019.18443

42. Fendrick AM, Brixner D, Rubin DT, et al. Sustained long-term benefits of patient support program participation in immune-mediated diseases: improved medication-taking behavior and lower risk of a hospital visit. J Manag Care Spec Pharm. 2021;27(8):1086-1095. doi:10.18553/jmcp.2021.20560

43. Fendrick AM, Macaulay D, Goldschmidt D, et al. Higher medication adherence and lower opioid use among individuals with autoimmune disease enrolled in an adalimumab patient support program in the United States. Rheumatol Ther. 2021;8(2):889-901. doi:10.1007/s40744-021-00309-9

44. Biosimilars Action Plan: Balancing Innovation and Competition. FDA; July 2018. Accessed October 31, 2024. https://www.fda.gov/media/114574/download

45. Joudyian N, Doshmangir L, Mahdavi M, Tabrizi JS, Gordeev VS. Public-private partnerships in primary health care: a scoping review. BMC Health Serv Res. 2021;21(1):4. doi:10.1186/s12913-020-05979-9

46. Helble M, Kuchenmüller T, Reeder J, et al. Collaborations between product development partnerships and the World Health Organization. Bull World Health Organ. 2023;101(5):355-357. doi:10.2471/BLT.22.289154