RT Journal Article SR Electronic T1 Validation of the Psoriatic Arthritis Impact of Disease (PsAID) Questionnaire and its potential as a single-item outcome measure in clinical practice JF Annals of the Rheumatic Diseases JO Ann Rheum Dis FD BMJ Publishing Group Ltd and European League Against Rheumatism SP annrheumdis-2017-211996 DO 10.1136/annrheumdis-2017-211996 A1 Richard Holland A1 William Tillett A1 Eleanor Korendowych A1 Charlotte Cavill A1 Nicola Waldron A1 Melanie Brooke A1 Neil J McHugh YR 2017 UL http://ard.bmj.com/content/early/2017/11/16/annrheumdis-2017-211996.abstract AB Objectives The Psoriatic Arthritis Impact of Disease (PsAID) Questionnaire is a recently developed patient-reported outcome measure (PROM) of disease impact in psoriatic arthritis (PsA). We set out to assess the validity in an independent cohort of patients, estimate the minimally important difference for improvement and explore the potential of individual components of the PsAID in clinical practice.Methods Data were collected prospectively for a single-centre cohort of patients with PsA. Construct validity was assessed by Spearman correlation with other PROMs and reliability by intraclass correlation coefficient (ICC) at 1 week. Sensitivity to change at 3 months was determined by the standardised response mean (SRM) in those patients with active disease requiring a change in treatment.Results A total of 129 patients (mean ±SD age 52.1±13.3, 57% women, disease duration 10.2±8 years) completed the baseline questionnaires and assessments. The mean baseline PsAID12 score was 3.92±2.26 with an ICC of 0.91 (95%CI 0.87 to 0.94). The SE of measurement was 0.51 and the minimal detectable change was 1.41. There was strong correlation (r≥0.70) with most of the PROMs studied and moderate correlation with clinical outcomes (r=0.40–0.57). The SRM of the PsAID12 was 0.74 (95%CI 0.45 to 0.97). There was strong correlation with individual PsAID items and their corresponding PROM questionnaires (r≥0.67).Conclusion The PsAID is a reliable, feasible and discriminative measure in patients with PsA. The good responsiveness of the PsAID and strong correlation of individual items with other PROMS represent an opportunity to reduce questionnaire burden for patients in studies and clinical practice.