Clinical outcomes in the first year of remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome.

Objective: We investigated clinical outcomes in patients with remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome.

Methods: This is a retrospective multicenter study conducted in Nagasaki, Japan. We consecutively diagnosed a total of 41 patients with RS3PE syndrome between October 2003 and September 2012 and evaluated their outcomes from medical records from the first year of follow-up.

Results: Although an excellent initial response to corticosteroids was noted in all 41 patients, 34 (82.9%) were still receiving corticosteroids and 13 (31.7%) showed elevated C-reactive protein (CRP) at one year. Multivariate analysis demonstrated that male gender and high CRP level at entry were independent variables associated with patients' one-year CRP level being ≥0.5 mg/dL. Odds ratios were 17.05 ([95% CI 2.41-370.12], p < 0.026) and 12.99 ([95% CI 1.78-269.62], p < 0.0096), respectively. Twenty-four patients (58.5%) were still receiving prednisolone (PSL) ≥ 5 mg/day at one year. Disease-modifying anti-rheumatic drugs including methotrexate were required in three patients (10.3%). Neoplasms were found in 14 patients (34.1%) and 1 of these had died due to lung cancer at one year.

Conclusions: RS3PE syndrome initially responds well to corticosteroids with remission of symptoms. However, outcomes of RS3PE syndrome appear to be worse than expected, and may be influenced by gender and initial CRP level.