POS0945 NON-RADIOGRAPHIC AXIAL SPONDYLOARTHRITIS IN THE AFRO-CARIBBEAN POPULATION, CLINICAL ASPECTS AND PARTICULARITIES
Authors: F. Louis-Sidney, D. Morillon, M. Blettery, L. Brunier, P. Numeric, M. De Bandt
Journal: Annals of the Rheumatic Diseases (2021)

Background: Spondyloarthritis is a polymorphic disease and the absence of diagnostic marker has led to propose diagnostic criteria for recognition. All the criteria, established in Caucasian populations, place at the center of the approach sacroiliac imaging and genetic terrain (HLA B27). For this reason, these criteria are not appropriate in populations lacking HLA B27. SPA is known to be rare in African populations and this rarity correlates with that of HLA B27.Prevalence of B27 in French West Indies is 2% (identical to the African populations). Objectives: We report clinical manifestations of SpA seen at the Fort de France University Hospital, with an emphasis on the so-called “non-radiographic SpA” (NRSPA). Methods: Adult patients with spondyloarthritis seen over a period of three consecutive months, were invited to participate in a survey and filled-in a self-administered questionnaire. The consulting rheumatologist specified the rheumatologic and extra-articular involvement, BASDAI score, HLAB27 data, markers of inflammation and imaging. Results: There were 93 patients, 47 with radiographic sacroilitis (RSPA) and 46 patients without but all - these 46 - had magnetic sacroilitis. This population is Afro-Caribbean for 98%. Mean age at onset of clinical signs is 38.5 ± 15.0 years and median age is 37.0 (13-77). An evocative family history is noted in 37%. All these 93 patients suffer from rachialgia. But the axial complaint is often secondary to the peripheral involvement. 3 patients have a mechanical spinal complaint. All the others have intermittent inflammatory complaint evolving by flares affecting all the spinal stages. 15/93 patients have isolated axial complain without peripheral disease. Enthesopathies are seen in 70%. Peripheral inflammatory joint complain is observed in 78 patients (84%), it is a bilateral and symmetrical chronic polyarticular pattern affecting (70/78) the small joints of the hands, forefeet and wrists. Ankle bi-arthritis is almost systematic and is observed in 71/78 patients; 8 patients with RSPA had no polyarthritis but oligo (6) or monoarthritis (2). Peripheral inflammatory joint is more frequent in NRSPA than in RSPA (98% vs 70%). Ultrasound individualises grade II synovitis (78/78), rarely with a Doppler effect (5/78). On average, more painful and swollen joints are observed in NRSPA than in RSPA. Extra articular and immunological aspects and activity scores are in table 1. Good sensitivity of peripheral arthritis to NSAIDs and MTX is noted in 94 and 91%. Conclusion: NRSpA are not uncommon in the Afro-Caribbean population, but are distinct from Caucasian SpA by several points: female predominance, rarity of B27 and syndesmophytes, frequency of polyalgic pattern, frequency of peripheral arthritis, rarity of extra-articular manifestations, more frequent but less marked inflammation, good response of arthritis to NSAIDs and MTX. Appropriate classification criteria for Afro-descendant populations is an urgent unmet need. References: [1](López-Medina C, et al. RMD Open 2019;5:e001108). Table 1. Extra articular manifestations, activity scores and immunological aspects of the patients. Item Results (%) NRSPA n=46 Results (%) RSPA n=47 Dactylitis 11 (23 %) 13 (27 %) Uvéïtis 5 (11 %) (p 0.02) 15 (32%) Psoriasis 1 (2 %) 1 (2 %) IBD 4 (9 %) (p 0.02) 10 (21 %) Balanitis 0 0 Non gonococcal urethritis 0 0 Non gonococcal cervicitis 0 0 High CRP (at least 2 measure) 21 (45%) (p 0.03) 30 (63%) Mean CRP mg/l 6 ± 4 17 ± 7 BASDAI 4.1 ± 0.2 4 ± 0.2 EVA pain 4.5 ± 0.4 4,5 ± 0.2 HAQ 0.6 ± 0.3 0,5 ± 0.2 EVA Global 4.9 ± 0.8 4,8 + 0.8 EVA Spine 5 ± 0.5 4,1 + 0.9 FIRST score &gt;5 5 /46 patients (10.9%) 6 / 47 patients (12.5%) HLA B27 presence 4/46 (8.7%) (p 0.01) 14/47 (29.8%) Sexe male 10 (21.3%) (p 0.001) male 19 (51.3%) ACPA 0 0 Latex Waaler-Rose 1 (low titer, &gt; 65 years) 1 (low titer, &gt; 65 years) ANA 2 (low titer, &lt; 1/320°) 3 (low titer, &lt; 1/320°) Disclosure of Interests: None declared