Psoriatic arthritis disease activity differs by race/ethnicity

BackgroundPsoriatic arthritis (PsA) affects up to 30% of individuals with psoriasis. Studies have demonstrated that the presenting disease severity and quality of life impact of psoriasis differs by race/ethnicity in patients with and without PsA, but little is known about disease activity among different racial/ethnic groups [1-3].ObjectivesThe objective of our study was to evaluate disease activity by race/ethnicity among patients with PsA.MethodsWe performed a cross-sectional study of adult (≥18 years old) patients with PsA who had at least one outpatient visit within the University of Pennsylvania health system between 2010 and 2019. Patients with PsA were identified by the presence of at least two International Classification of Diseases (ICD)-9 or ICD-10 codes for PsA associated with two different healthcare encounters. The primary outcome was disease activity as measured by the Routine Assessment of Patient Index Data 3 (RAPID3) assessment. The RAPID3 score is a validated patient-reported measure of physical function, pain, and global status [4]. RAPID3 scores range from 0 to 30, with higher scores indicating greater disease activity. Patients were included if they had at least one documented RAPID3 score. For patients with multiple RAPID3 scores, the median value was used. The primary independent variable was race/ethnicity categorized as White (reference), Black, Asian, Hispanic, or other race. Multivariable linear regression was used to assess the relationship between race/ethnicity and RAPID 3 score.ResultsThe study population included 742 patients. Mean (standard deviation [SD]) age was 47.2 (13.3) years and 57.4% were female. The racial/ethnic distribution was 79.4% White, 7.0% Black, 5.0% Asian, 3.1% Hispanic, 2.6% other race, and 3.0% missing race/ethnicity. The means of the median Rapid3 scores were statistically significantly different across racial/ethnic groups (p<.001): White mean (SD) 9.79 (6.02), Black mean (SD) 14.86 (14.86), Asian mean (SD) 9.79 (5.44), Hispanic mean (SD) 15.09 (7.11), other race mean (SD) 10.57 (6.91). In an adjusted multivariable model controlling for other sociodemographic factors, body mass index, treatment history, and medical comorbidity, Hispanic patients had higher RAPID3 scores compared to White patients, indicating greater disease activity (β 3.36; 95% confidence interval [CI] 1.04 – 5.67, p <.005). In exploratory stratified analyses to evaluate effect modification by sex, among males, Black (β 3.43; 95% CI 0.23 – 6.63, p=.04) and Hispanic (β 5.94; 95% CI 2.18 – 9.70, p <.005) patients had higher RAPID3 scores than White patients. Among females, no significant racial/ethnic differences in RAPID3 scores were identified.ConclusionBlack and Hispanic patients report greater disease activity as indicated by higher RAPID3 scores compared to White patients. Larger studies are necessary to confirm our findings and understand the causes of racial/ethnic differences in disease activity among patients with PsA.References[1]Abrouk M, Lee K, Brodsky M, Nakamura M, Singh R, Zhu TH, et al. Ethnicity affects the presenting severity of psoriasis. J Am Acad Dermatol. 2017;77(1):180-2.[2]Shah SK, Arthur A, Yang YC, Stevens S, Alexis AF. A retrospective study to investigate racial and ethnic variations in the treatment of psoriasis with etanercept. J Drugs Dermatol. 2011;10(8):866-72.[3]Takeshita J, Augustin M, de Jong E, Lafferty K, Langholff W, Langley R, Leonardi C, Menter A, Alexis A. Psoriasis-Related Quality-of-Life Differs by Race/Ethnicity. J Invest Dermatol. 2019; 139(5S, Supplement 1):S148.[4]Coates LC, Tillett W, Shaddick G, Pincus T, Kavanaugh A, Helliwell PS. Value of the Routine Assessment of Patient Index Data 3 in Patients With Psoriatic Arthritis: Results From a Tight-Control Clinical Trial and an Observational Cohort. Arthritis Care Res (Hoboken). 2018;70(8):1198-1205.Disclosure of InterestsFahad Ahmed: None declared, Alexis Ogdie Consultant of: A. Ogdie has received consulting fees from Amgen, AbbVie, Bristol Myers Squibb, Celgene, CorEvitas (formerly Corrona), Gilead, Janssen, Lilly, Novartis, Pfizer, and UCB., Grant/research support from: A. Ogdie has received grant support from the National Institutes of Health/National Institute of Arthritis and Musculoskeletal and Skin Diseases, Rheumatology Research Foundation, National Psoriasis Foundation, Abbvie (University of Pennsylvania), Pfizer (University of Pennsylvania), Amgen (FORWARD), and Novartis (FORWARD)., Robert Fitzsimmons: None declared, Daniel Shin: None declared, Junko Takeshita Consultant of: JT has served as a consultant for Pfizer Inc. and Janssen Biotech receiving honoraria., Grant/research support from: JT has received a research grant (to the Trustees of the University of Pennsylvania) from Pfizer Inc.