Association of clinical and sonographic factors with discrepancy between patients' and evaluators' global assessments in psoriatic arthritis.

OBJECTIVES

To evaluate the discordance between patients' global assessments (PGA) and evaluators' global assessments (EGA) in psoriatic arthritis (PsA), and to explore the association of clinical variables, patient-reported outcomes (PROs) and ultrasound (US) factors with this discordance.

METHODS

Consecutive PsA patients (CASPAR criteria) were prospectively recruited and evaluated by a comprehensive clinical examination, PROs and sonographic assessment (including 52 joints, 40 tendons and 14 entheses). EGA was scored by rheumatologists blinded to the PGA. Discordance between PGA and EGA was considered significant if the delta was ≥3. The US assessor was blinded to the clinical data. The concordant and discordant groups were compared, and factors associated with discordance were evaluated through a multivariate regression analysis.

RESULTS

Of the 158 PsA patients who were included, 88 (55.7%) patients were considered discordant, with the mean difference between PGA and EGA of 3.3. The discordant group had significantly higher tender joint counts (TJC), enthesitis, C-reactive protein (CRP) and lower working status rates compared with the concordant group (P < 0.05). US scores were similar between the groups. Patients with discordance had significantly higher PsA activity scores, a higher prevalence of fibromyalgia and worse PROs, including pain, depression, fatigue and measures of quality of life (P < 0.05). On multivariate regression, higher TJC, lower swollen joint counts and depression were associated with greater discordance (OR 1.07, OR 0.85 and OR 1.05, respectively, P < 0.05).

CONCLUSION

The discrepancy between PGA and EGA in PsA is characterized by worse disease activity scores and worse subjective measures but not by sonographic measures.