To investigate in primary Sjögren's syndrome, the differences between patients with and without widespread pain (WSP) with respect to the cumulative prevalence of extra-glandular manifestations (EGMs) and systemic auto-antibodies.
All outpatients diagnosed with primary Sjögren's syndrome (2) were included in a prospective follow-up, with at least one check up each year, from June 1991 until November 2011. Patients who also fulfilled criteria for concomitant connective tissue disorders were excluded. Widespread pain was defined as the presence of long-lasting (>one year) diffuse pain in all four body quadrants. Data were collected with respect to the cumulative prevalence of systemic auto-antibodies (anti-nuclear antibodies [ANA], anti-Sjögren syndrome A antigen [anti-SSA], anti-Sjögren syndrome B antigen [anti-SSB] and immunoglobulin M-Rheumatoid factor [IgM-RF]) and EGMs related to primary Sjögren's syndrome.
Eighty-three patients were included in the final analysis. Thirty-nine (34.9%) patients had widespread pain. Anti-SSB was found less frequently (p<0.05) in patients with WSP than in patients without WSP. The WSP-positive patients were more frequently negative for all four tested autoantibodies (p<0.05). The patients with WSP had fewer EGMs than the patients without WSP (p<0.01); more specifically, polyneuropathy occurred less frequently (p<0.05) in the patients with WSP. Cytopenia, uveitis, pericarditis, pleuritis, interstitial lung disease, vasculitis, monoclonal gammapathy of unknown significance and non-Hodgkin lymphoma only occurred in the patients without WSP.
Primary Sjögren's patients with WSP form a benign subgroup, with a lower prevalence of anti-SSB and EGMs (in particular polyneuropathy). We suggest a shorter period of follow-up for this subset than for the WSP-negative patients.