New Care Model Improves Early PsA Diagnosis in Psoriasis Patients

Due to a higher rate of undiagnosed psoriatic arthritis (PsA) in psoriasis patients, a new care model suggests that musculoskeletal (MSK) ultrasounds, triage questionnaires, and clinical assessments by an advanced practice physiotherapist should be utilized to help identify patients with PsA with MSK symptoms. These findings were presented at the 2017 ACR/ARHP Annual Meeting.

Often, poor patient outcomes are reported among patients with psoriasis due to delays in diagnosis. In an effort to create a novel model of care that involved a self-referral system and central triage clinic for psoriasis patients with MSK symptoms to compare the efficacy of several triage methods for PsA, researchers invited patients with psoriasis to contact the research team if they were experiencing MSK symptoms. 

The participants who joined were assessed in a central triage clinic to determine the likelihood of PsA. The researchers used a multi step triage process to determine diagnoses that included:

• three PsA screening questionnaires (TOPAS-2, PEST, PASE);

• MSK ultrasound assessment of symptomatic joints and entheses;

• clinical assessment by an advanced practice physiotherapist; and,

• levels of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).

Of the 1159 participants invited, 300 responded (26%) and 152 (13%) agreed to be a part of the study. According to the findings, of the participants assessed in the clinic, 69 (73%) did not have PsA, 17 (18%) had possible PsA, and 8 (9%) had PsA. The advanced practice physiotherapist’s assessment in detecting clinical PsA was highly sensitive (100%) with good specificity (71%). Further, the screening questionnaires varied by their sensitivity and specificity with TOPAS-2 showing highest sensitivity (88%) and Psoriatic Arthritis Screening and Evaluation with highest specificity (87%).

Additional study results demonstrated that the prevalence of positive MSK inflammation by ultrasound (at least 1 joint or enthesis with positive power Doppler signal) was 39.4%. The sensitivity of positive MSK ultrasound was high (88%) but its specificity was moderate (65%). The performance of CRP and ESR as triage methods was poor.

Notably, 22% of the study participants who had positive MSK ultrasound findings were not classified by the rheumatologist as having PsA.

—Julie Gould