In daily practice, we noticed that hand osteoarthritis (OA) was commonly associated with primary Sjögren syndrome (pSS). Therefore, we aimed to investigate its prevalence in patients with pSS in a controlled study.
The study included patients with pSS and controls with systemic lupus erythematosus (SLE). Standard hand/wrist radiographs were obtained and classified according to the Kellgren-Lawrence system. "Erosive hand OA" was defined according to the Verbruggen-Veys classification.
There were 114 patients with pSS (110 women, 51.0 yrs) and 34 patients with SLE (33 women, 42.4 yrs). Among 114 patients with pSS, 42.7% had radiographic, 30.3% symptomatic, and 16.0% erosive hand OA. The prevalences of radiographic (45.5%) and erosive hand OA (14.4%) in 90 patients with pSS with age- and sex-matched patients with SLE were significantly higher than those in patients with SLE (14.7% and 0.0%, p = 0.007 and p = 0.012, respectively). Interobserver reliabilities for diagnosing radiographic and erosive OA were found to be good (ĸ = 0.780 and ĸ = 0.788, respectively). Intraobserver reliabilities for diagnosing radiographic and erosive OA were also good (ĸ = 0.784 and ĸ = 0.825 for FO, and ĸ = 0.722 and ĸ = 0.800 for AB, respectively). The frequency of hand OA in patients with pSS was found to be increased with increasing age (r = 0.513). The mean age of those with erosive hand OA was significantly higher than those without erosive OA (p < 0.001).
This study suggests that pSS, conversely to SLE, is more frequently associated with hand OA.