Clinical and laboratory profiles of systemic lupus erythematosus associated with Sjögren syndrome in China: a study of 542 patients

This study aims to investigate the clinical and laboratory features of systemic lupus erythematosus (SLE) patients associated with Sjögren syndrome (SS) in China, as well as its similarities to and differences from SLE patients without SS. A group of 542 consecutive unselected SLE patients was recruited. Diagnosis of SLE was made according to 1997 revised American College of Rheumatology SLE criteria; SS was diagnosed using the American–European classification criteria. Clinical and laboratory parameters in SLE patients with SS (SLE-SS) were compared with those in SLE patients without SS (SLE-no SS). Overall, SS was identified in 35 SLE patients (6.5%); the onset of SS preceded the development of SLE in 17 of them (48.6%). Compared with the SLE-no SS group (35.8 ± 10.5 years), patients with SLE-SS (41.3 ± 11.6 years) were significantly older (P = 0.003), had a higher frequency of anti-Ro/SSA, anti-La/SSB, and anti-dsDNA antibodies, but had a significantly lower frequency of renal involvement. This study demonstrates that SLE-SS may be a subgroup of patients with characteristic clinical and laboratory features. To improve the treatment outcomes in SLE-SS patients, more specific treatment should be applied based on those factors.