- The Psoriatic arthritis UnclutteRed screening Evaluation (PURE)-4 scale, based on 4 symptoms, has high diagnostic value for psoriatic arthritis (PsA) in patients with psoriasis.
Why this matters
- Up to 15.5% of patients with psoriasis have undiagnosed PsA, suggesting need for a short and easy-to-perform screening tool.
- Evocative signs of dactylitis (OR, 23.1; P=.050), inflammatory heel pain (OR, 12.7; P=.0003), bilateral buttock pain (OR, 9.9; P=.008), and peripheral joint pain with swelling in patients aged <50 years (OR, 5.0; P=.029) were associated with PsA in multivariate analysis and included in the PURE-4 scale.
- ≥1 positive item on PURE-4 was associated with 85.7% sensitivity, 83.6% specificity, positive predictive value of 48.7%, negative predictive value of 97.0%, and area under the receiver operating curve of 87.6% for diagnosis of PsA.
- 137 patients with psoriasis (15.3% with PsA) were analyzed by the PURE-4 scale to determine its diagnostic utility.
- The 4 items included in PURE-4 were selected by multivariate logistic regression from an initial group of 23 items identified from the literature review.
- Funding: MSD France.
- Small patient sample size.
- No external validation.