Background Despite the role of chronic low-grade inflammation in osteoarthritis (OA), prevalence of OA during inflammatory or auto-immune diseases remains poorly assessed. A single study without a valid control group  and daily practice suggest an increased frequency of hand OA (HOA) in primary Sjögren Syndrome (pSS).
Objectives We aimed investigate the prevalence of radiographic, symptomatic or erosive HOA in pSS and to compare these results with age and sex-matched control population suffering from dry eyes and mouth without auto-immune manifestation (sicca patients).
Methods We included women with pSS fulfilling 2002 AECG European-American criteria and control women suffering from sicca symptoms without autoimunity who underwent a multidisciplinary day hospital. Standardized radiographs of hands were performed and were all read by an experimented reader. Radiographic HOA was defined as Kellgren-Lawrence score ≥2 on at least one joint. Erosive HOA was defined using the Verbruggen scoring system (phase E, subchondral erosion or R, remodelling of subchondral plate). Symptomatic HOA was defined as radiographic HOA associated with spontaneous hand joint pain and/or with a FIHOA ≥5 at the time of radiographs. We compared pSS versus sicca patients, pSS with radiographic HOA (pSS+, HOA+) versus pSS without radiographic HOA (pSS+, HOA-), and finally pSS with radiographic HOA (pSS+, HOA+) versus sicca patients with radiographic HOA (pSS-, HOA+).
Results We included 34 patients with pSS (median age [range] 54.5 [28–84] years) and 54 patients with only sicca symptoms (57 [24–85] years). Among pSS patients, 41% had radiographic HOA, 12% had symptomatic HOA and 9% had erosive HOA. These prevalences did not differ from sicca patients (52% radiographic HOA p=0.45, 28% symptomatic HOA p=0.11, 9% erosive HOA p=1.0). The trend for a higher prevalence of symptomatic HOA in sicca patients compared to pSS is expected since these patients frequently suffer from dryness associated with fibromyalgia. In pSS patients, radiographic HOA was associated with a higher average age (pSS+HOA+:63,5 versus pSS+HOA-: 48,5 years old, p<0,01), with menopause (pSS+HOA+: 100% versus pSS+HOA-: 45%, p<0,01) and hypothyroidism (pSS+HOA+: 64% versus pSS+HOA-: 25%, p=0.04). There was no pSS feature such as autoantibodies profile or pSS disease activity, associated with radiographic or symptomatic HOA. Finally, HOA symptoms did not differ between patients with pSS and sicca symptoms. The prevalence of radiographic and erosive HOA in pSS and non-autoimmune sicca group seems in the same range as that observed in women from Framingham's cohort (44% and 10% respectively). And prevalence of symptomatic HOA seems similar in the pSS (12%) and in women from Framingham's cohort (16%).
Conclusions The prevalence of HOA is not increased in pSS, a model of auto-immune diseases. Patients with pSS have the same HOA risk factors than in general population (age and menopause) and also hypothyroidism that may be involved in OA pathophysiology.
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Acknowledgements Osteoarthritis group of French Society of Rheumatology.
Disclosure of Interest None declared