FRI0184 High prevalence of hidradenitis suppurativa, especially in female axial spondyloarthritis patients with high disease activity and poor quality of life
Authors: A. Rondags, S. Arends, F. Wink, B. Horvath, A. Spoorenberg
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Hidradenitis suppurativa (HS) is a chronic debilitating inflammatory skin disease. Although HS and axial spondyloarthritis (SpA) share common denominators in the pathogenesis and treatment, little is known about HS associated patient characteristics in axial SpA. <h3>Objectives</h3> To identify patient characteristics associated with HS in a large cohort of axial SpA patients. <h3>Methods</h3> In this cross-sectional study, a self-screening questionnaire based on validated diagnostic HS questions was sent to all axial SpA patients from the Groningen Leeuwarden Axial Spondyloarthritis (GLAS) cohort. Verification of HS diagnosis was done by reviewing medical records for dermatologists diagnosis of HS and by telephone using another validated diagnostic HS question. These HS questions showed previously high sensitivity and specificity (92%–97%<sup>1</sup> and 97%<sup>2</sup>, resp.). Comparative analysis for axial SpA patients with versus without HS was performed. Multivariable logistic regression analysis of patient characteristics was performed to investigate independent predictors for HS in axial SpA. <h3>Results</h3> In total, 75.6% (449/592) questionnaires were eligible for analyses. Included patients had a mean age of 50±13 years, 63% were male, mean symptom duration was 23±13 years, and 78% were HLA-B27 positive. HS diagnosis could be confirmed in 41 of the 449 respondents, resulting in an estimated prevalence of 9.1%. Assuming that all non-responders never had HS, the minimal HS prevalence rate would be 6.9% (41/592). In comparison to patients without a positive history of HS, these patients were more frequently female (54% vs. 35%, p=0.02), showed higher axial SpA disease activity (mean BASDAI 4.5 vs. 3.6, p=0.01 and ASDAS<sub>CRP</sub>2.6 vs. 2.2 p=0.003), and worse quality of life (QoL) (median ASQoL 9.0 vs. 4.0, p&lt;0.001). Also, a history of heel enthesitis and dactylitis was more prevalent (34% vs. 19%, p=0.03% and 15% vs. 6%, p=0.05, respectively). Multivariable analysis showed that a higher score on ASDAS was independently associated with HS (OR: 1.639, 95% CI 1.176–2.284). <h3>Conclusions</h3> In our cohort of axial SpA patients, HS is more prevalent than in the general population (6.9%–9.1% and ~1% resp.).<sup>3</sup> HS is associated with high ASDAS, especially in female patients experiencing poor QoL. Additionally, heel enthesitis and dactylitis seems also to be more prevalent in axial SpA patients with HS. <h3>References</h3> [1] Esmann S, et al. Questionnaire-based diagnosis of hidradenitis suppurativa: Specificity, sensitivity and positive predictive value of specific diagnostic questions. Br J Dermatol2010;163:102–6. [2] Vinding GR, et al. The prevalence of inverse recurrent suppuration: A population-based study of possible hidradenitis suppurativa. Br J Dermatol2014;170:884–9. [3] Miller IM, et al. Prevalence, risk factors, and comorbidities of hidradenitis suppurativa. Dermatologic Clinics2016;34:7–16. <h3>Disclosure of Interest</h3> A. Rondags: None declared, S. Arends Grant/research support from: Pfizer, F. Wink Consultant for: Abbvie, B. Horvath Grant/research support from: Abbvie, Janssen-Cilag, Novartis, Consultant for: Abbvie, Janssen-Cilag, Novartis, A. Spoorenberg Grant/research support from: Pfizer, Abbvie, Consultant for: Pfizer, Abbvie, MSD, UCB, Novartis