Disease-modifying anti-rheumatic drugs for refractory severe knee synovitis in patients with peripheral spondyloarthritis: efficacy and predictors of response

Abstract

Objectives: In this study we aimed to evaluate the efficacy of disease-modifying anti-rheumatic drugs (DMARDs) for severe knee synovitis, refractory to low-dose oral corticosteroids and/or non-steroidal anti-inflammatory drugs (NSAIDs) and intra-articular (IA) corticosteroid injections, in patients with peripheral spondyloarthritis (SpA). We also examined the association between the clinical response of knee synovitis and demographic and clinical parameters of the studied patients.

Method: Patients with SpA-related arthritis including resistant and severe knee synovitis, defined as the presence of swelling, tenderness, and a decreased range of movement on clinical examination, treated with DMARDs between January 2005 and January 2012 were studied retrospectively. No evidence of knee synovitis was considered a clinical response to DMARDs.

Results: Forty-five patients [mean age 41.0 ± 1.9 years; 33 (73.3%) males] were studied. In 14 (31.1%) of the patients there was a clinical response of knee synovitis, while the remaining 31 (68.9%) patients were non-responders. Response to DMARD therapy was associated with disease subtype (p = 0.011) and HLA-B27 (p = 0.023) but not with a history of psoriasis (p = 0.067) or age at disease onset (p = 0.054). However, only a history of psoriasis could independently predict the response to DMARDs [adjusted odds ratio (OR) 0.232, p = 0.049].

Conclusions: One-third of the patients with peripheral SpA and severe resistant knee synovitis had a clinical response to DMARD therapy. Disease subtype and HLA-B27 were associated with the response of knee synovitis to DMARDs, but only psoriasis could independently predict this response.

Acknowledgements

We thank Stergios Polyzos for providing expert advice on our statistical analysis.