More than one-third of patients with psoriatic arthritis (PsA) present with widespread nonarthritic pain, which was associated with worse patient-reported scores and failure to achieve minimal disease activity (MDA) after treatment with conventional synthetic or biologic disease-modifying antirheumatic drugs, according to results of the exploratory, prospective cohort study published in Arthritis Care & Research.
The study was designed to investigate the prognostic value of widespread nonarthritic pain and of musculoskeletal ultrasound examination on subsequent treatment outcomes among patients with PsA. Clinical, ultrasound, and patient-reported measures were retrieved at baseline and after 4 months. Widespread pain was defined as a Widespread Pain Index ≥4, with pain in ≥4 of 5 regions. PsA activity based on ultrasound examination was defined as positive or negative color Doppler findings in selected entheses, joints, or tendons. The key response criteria included American College of Rheumatology 20% improvement response, Disease Activity in Psoriatic Arthritis 50%, and MDA.
A total of 69 patients were enrolled in the study, with widespread pain reported in 35% of participants. Widespread pain was associated with worse patient-reported and composite baseline measures, whereas ultrasound and other objective findings were similar among those with and without widespread pain. The odds of 4-month MDA were significantly higher among patients who were enrolled without widespread pain (odds ratio [OR], 18.43; 95% CI, 1.51-224.41; P =.022), whereas widespread pain did not impair other measures of response. Although 61% of patients with baseline color Doppler activity exhibited worse PsA burden, their likelihood of treatment response was comparable to that of those without color Doppler.
The investigators concluded that PsA activity by color Doppler had no effect on subsequent treatment response among patients with PsA. The presence of widespread pain at baseline was strongly correlated with failure to meet MDA criteria after the use of immunomodulatory therapy.
Højgaard P, Ellegaard K, Nielsen SM, et al. Pain mechanisms and ultrasonic inflammatory activity as prognostic factors in patients with psoriatic arthritis: a prospective cohort study [published online July 5, 2018]. Arthritis Care Res (Hoboken). doi: 10.1002/acr.23693