Comparison of complications during 1-year follow-up between remitting seronegative symmetrical synovitis with pitting edema syndrome and elderly-onset rheumatoid arthritis

Remitting seronegative symmetrical synovitis with pitting edema syndrome (RS3PE), a rheumatic disease affecting the elderly, responds well to corticosteroids; however, our RS3PE patients' corticosteroid therapy is longer than expected. Elderly-onset rheumatoid arthritis (EORA) patients are reported to be at a significantly increased risk for steroid-related side effects including cardiovascular diseases (CVDs). To clarify the complications during a 1-year follow-up in corticosteroid-treated RS3PE patients compared to EORA patients. We retrospectively analyzed the records of 47 RS3PE patients (28 men, 19 women, age 78.4 +/- 7.5 years) and 46 EORA patients (10 men, 36 women; 77.0 +/- 6.8 yrs) to compare the complications over a 1-year follow-up. The RS3PE and EORA groups' average initial PSL doses were 16.5 +/- 7.2 mg/day and 7.3 +/- 4.6 mg/day, respectively. During the 1-year follow-up after treatment, there was no significant increase in CVDs in both groups. However, infections occurred in nine RS3PE patients, which is a significantly higher incidence compared to the EORA patients with infections (n = 3). The initial PSL dose was the independent variable associated with the incidence of infection. Infections were significantly increased during elderly RS3PE patients' steroid therapy. The initial corticosteroid dose was an infection-risk factor.Key messages Infections are increased during steroid therapy in elderly patients with RS3PE syndrome. The initial dose of corticosteroids was one of the risk factors for infections.