Assessment of Crystals in the Synovial Fluid of Psoriatic Arthritis Patients in Relation to Disease Activity

Background: This study examines the relationship between the presence of crystals in the synovial fluid of patients with psoriatic arthritis (PsA) and disease activity. Methods: The synovial fluid of 156 PsA patients was analyzed and compared to 50 patients with gonarthrosis (GoA). The Leica DM4500P polarization microscope was used for crystal detection. Results: The presence of crystals was observed in 23.71% of PsA patients and none of the GoA patients, p < 0.001. Monosodium urate crystals (67.58%) and calcium pyrophosphate crystals (21.62%) were prevalent. The presence of crystals in the synovial fluid of PsA patients was associated with high disease activity according to the Composite Psoriatic Disease Activity Index (OR = 18.75, 95%; CI: 7.13 to 49.25) and the Disease Activity for Psoriatic Arthritis (OR = 15.96, 95%; CI: 5.76 to 44.23), with severe disability according to the Health Assessment Questionnaire Disability Index (OR = 13.60, 95%; CI: 5.09 to 36.31), and with severe pain on the Visual Analog Scale (OR = 157.25, 95%; CI: 39.50 to 625.94). Conclusion: Our results suggest that synovial fluid examination should be included in the treatment pathway for PsA patients with active disease, to aid in determining whether urate-lowering therapy is required.

Automated summary

This study found that the presence of crystals in the synovial fluid of PsA patients is associated with disease activity, disability, and pain. The findings suggest that examining synovial fluid can be helpful in determining treatment options for PsA patients.