Session Information
Session Type: Abstract Submissions (ACR)
Background/Purpose: Psoriatic arthritis (PsA) is characterised by involvement of both the appendicular and axial skeleton. Little is known about the clinical predictors of sacroiliitis (SI), especially regarding underlying patient’s characteristics, life style, correlation with skin disease and with severity of psoriatic disease. The objectives of our study were: 1) To investigate the prevalence of SI in an ethnically homogenous cohort of established PsA, 2) to identify clinical and genetic predictors of SI in patients with PsA, 3) to describe different radiographic patterns of SI and their potential associations with clinical and genetic characteristics.
Methods: A cohort of 283 PsA patients, fulfilling CASPAR criteria, was included. Following informed consent, patients underwent a detailed skin and rheumatologic assessment including PASI, body surface area for Psoriasis (PsO), CRP, ESR, smoking, BMI status, alcohol intake, education status, family history of PsO and/or PsA, PsA duration, age of PsO/PsA onset, enthesitis, dactylitis, erosions, osteolysis, arthritis mutilans, clinically deformed joints, PsO and/or PsA requiring TNFi treatment, HAQ, DLQI, Bristol Rheumatoid Arthritis Fatigue Numeric Rating Scale (BRAF-NRS), and EQ5D. In addition, HLA-B*27 and B*080101 status was recorded, which we have recently shown are the key genetic markers of radiographic SI (www.rheumatology.org/education/annual/2012_abstract_supplement.pdf). Unilateral or bilateral grade 2 radiographic changes were required for inclusion as having SI. SI involvement was further defined as asymmetrical when radiographic scoring grades were discordant between the 2 SI joints and as unilateral when the opposite SI joint was completely uninvolved.
Results: 70 patients (25%) had radiographic SI; all either had present or past history of backache. Mean age of patients with SI was 51.6±11 years, and 53.5% were male. Unilateral SI was present in 14 patients (27%); bilateral SI in 38 patients (73%). Of those with bilateral involvement, SI was asymmetrical in 28 (73%) patients. HLA-B*0801 was significantly associated with asymmetrical SI, which included those with unilateral SI or asymmetrical bilateral involvement (p=0.001), and in striking contrast, HLA-B*2705 was significantly associated with bilateral symmetrical SI (p=<0.001). On backward step-wise multiple regression analysis, model predicted significant association of peripheral joint erosions (OR 1.91, p=0.03), PASI maximum (OR 1.05, p=0.03), younger PsA age of onset (OR 0.93, p=<0.001), presence of HLA-B*0801 (OR 2.9, p=0.001) and HLA-B*2705 (OR 2.39, p=0.02) with SI.
Conclusion: Twenty five percent of PsA patients developed SI on long-term follow up. PsA developing at younger age, severe skin PsO, peripheral joint erosions, HLA-B*0801 and HLA-B*2705 are clinical and genetic predictors for the development of SI. We report for the first time that there are two separate principal patterns of HLA antigens explaining 2 clinically distinct sub-types of radiographic SI.
Disclosure:
M. Haroon,
None;
A. Szentpetery,
None;
P. Gallagher,
None;
R. Winchester,
None;
O. FitzGerald,
Pfizer, Abbott, UCB, Roche, MSD, BMS,
2,
Janssen Pharmaceutica Product, Pfizer, Abbott, Roche, MSD, BMS,
5,
Pfizer, Abbott, UCB, Roche, Janssen,
8.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/hla-b0801-is-strongly-associated-with-asymmetrical-sacroiliitis-and-hla-b27-with-symmetrical-involvement-in-psoriatic-arthritis-results-of-a-long-term-follow-up-study-examining-clinical-and-genetic/