Assessing flares in patients with psoriatic arthritis using questionnaires

The psoriatic arthritis (PsA) FLARE Questionnaire was developed to study flares in PsA. We aimed to validate the FLARE Questionnaire and compare it with the Psoriatic Arthritis Impact of Disease 12-item Questionnaire (PsAID-12) to determine whether PsAID-12 was sufficient for assessing disease flares.

This cross-sectional study enrolled 150 patients aged ≥18 years. Data collection using a standard protocol consisted of demographic characteristics, patient-reported outcomes (including PsAID-12), cutaneous/musculoskeletal examination findings, routine labs, FLARE Questionnaire and a stand-alone question asking participants whether they believed they were experiencing a flare. Internal consistency of the FLARE Questionnaire was measured using Cronbach's α. Test-retest reliability was evaluated using the intraclass correlation coefficient (ICC) by administering the questionnaire twice to 51 patients, 1 week apart. Agreement between flare definition using the FLARE Questionnaire and the stand-alone question was determined using Cohen's κ. Associations between clinical features and flares self-reported by the stand-alone question were assessed using logistic regressions. The FLARE Questionnaire and PsAID-12 were compared against the stand-alone question using receiver operating characteristics (ROC) curve analysis.

The FLARE Questionnaire displayed good internal consistency (α = 0.88, 95% CI 0.85 to 0.90), good test-retest reliability (ICC = 0.76, p<0.001, 95% CI 0.59 to 0.87), and moderate agreement between flare definition using the cut-off and stand-alone question (κ = 0.59, 95% CI 0.45 to 0.72). However, ROC analysis demonstrated that the FLARE Questionnaire (area under the curve (AUC) = 0.90, 95% CI 0.85 to 0.95) and PsAID-12 (AUC = 0.83, 95% CI 0.76 to 0.90) performed similarly. A PsAID-12 cut-off of ≥3.13 achieved the best balance between sensitivity (0.72) and specificity (0.79).

PsAID-12 may be used for defining PsA flares.