Validation of the Italian version of proposed GRAPPA flare questionnaire for patients with psoriatic arthritis

OBJECTIVES: The aim of the present study was to validate an Italian version of the GRAPPA flare instrument to identify patients with psoriatic arthritis (PsA) with a possible disease flare. METHODS: This was a cross-sectional study enrolling consecutively PsA patients classified with CASPAR criteria. Inclusion criteria were: age ≥18 years and stable treatment (at least six months of follow-up) with conventional synthetic or biological DMARDs. The flare questionnaire was administered at baseline and within a two-week interval. Internal consistency of the questionnaire was evaluated with Cronbach's alpha coefficient. Construct validity of flare questionnaire was assessed using the correlation between flare score and disease activity indices, HAQ and serum C-reactive protein. Cohen's κ was performed to assess the agreement level between the patient's perception of flare and the score of the questionnaire. Finally, test-retest was performed to assess the reliability of the instrument. RESULTS: 46 PsA patients were enrolled in this study. Of these, 30.4% reported a status of flare of their disease. The questionnaire was internally consistent (alpha=0.81). Moreover, the questionnaire score correlated with the main disease activity indices (Spearman Rho ranging from 0.30 to 0.66; p<0.01). The score of flare questionnaire showed a moderate agreement with the perception of flare from the patients (Cohen's κ=0.54). Test-retest reliability showed a good intra-class correlation. CONCLUSIONS: This initial validation of the Italian version of the GRAPPA flare instrument was favourable. Our results confirm the utility of this questionnaire in the assessment of flare in PsA.