Psoriatic arthritis impact of disease questionnaire: validity, reliability and its clinical potential

The psoriatic arthritis impact of disease (PSAID) questionnaire has been developed to measure disease impact on patients with psoriatic arthritis. It was aimed to evaluate its validity and reliability in association with sociodemographic and clinical factors and compare it with disease activity and patient-reported outcome measures in a Turkish psoriatic arthritis population. A prospective observational study was conducted to validate the Turkish version of the PSAID. All consecutive patients with psoriatic arthritis were evaluated between January 2019 and October 2019. Demographic and clinical features were recorded. The PSAID and patient-reported outcome measures were applied to all patients. Interclass and intra-class correlation analyses were performed. Convergent validity and correlation coefficients were used for validity analyses. There were 80 patients with a mean age of 50.2 ± 9.9 years. Cronbach's α value of the PSAID and intra-class correlation were 0.799 and 0.984, respectively. The total median PSAID score was 4.7. Pain, fatigue, ability to work, functional capacity and feeling of discomfort were the five highest-scoring subscales. There was satisfactory internal consistency for each subscale of the PSAID. As disease severity increased from low to high, the PSAID scores significantly increased. There were acceptable correlations between the PSAID and other patient-reported outcome measures. The PSAID is shown to be a reliable and valid questionnaire in Turkish patients with psoriatic arthritis. Good correlation with disease activity and patient-reported outcome measures represent an opportunity to use the PSAID in clinical practice to tailor individualized treatment choices.