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complete, making it suitable for use in both research and clinical settings.
However, the PsAQoL has been little used to date [ 57 – 61 ]. Furthermore, it is subject
to copyright.
The PsAID Questionnaire
The European League Against Rheumatism (EULAR) recently developed the
PsAID (Psoriatic Arthritis Impact of Disease) questionnaire, a multidimensional
patient-reported questionnaire to assess the impact of PsA from the patient’s per-
spective [ 52 ]. The objective was to develop a questionnaire that can be used to
calculate a score, refl ecting the impact of PsA based on the patients’ perspective.
The questionnaire has been developed by a mixed group of rheumatologists/
researchers, patient research partners, and health professionals, including an
International Classifi cation of Health and Functioning expert and a nurse practitio-
ner/researcher. Compared to existing instruments, the PsAID score is unique
because it has been developed with the active involvement of 11 patient research
partners from 11 European countries. Therefore the instrument is fully based on the
patient perspective of the illness [ 62 ].
First, the 11 patient research partners identifi ed 16 domains (areas of health)
important for patients with PsA; then 139 patients prioritized the 16 domains
according to importance and the lowest priority 4 domains were excluded from the
next steps. NRS questions were developed, one for each of the 12 domains of health.
To combine the domains into a single score, relative weights were determined for
each domain, based on relative importance as reported by 474 PsA patients from
across Europe. At the same time, an international cross-sectional and longitudinal
validation study was performed in 13 countries (474 patients) to validate the PsAID
in terms of psychometric properties, regarding cross-sectional relation with other
well-known outcome measures, and longitudinal validation for reliability and sen-
sitivity to change in smaller samples ( N = 80 and 71, respectively). The measures
performed well; reliability was high (intra-class correlation coeffi cient, 0.95, 95 %
confi dence interval 0.92–0.96) and so was sensitivity to change (standardized
response mean 0.90) [ 52 ].
There are two versions of the PsAID. For clinical practice the 12-item version is
recommended. This version covers pain, skin problems, fatigue, work and/or leisure
activities, functional capacity, discomfort, sleep disturbance, anxiety/fear and
uncertainty, coping, embarrassment and/or shame, social participation, and depres-
sion (Table 5.4 , Appendix 3 ).
For clinical research (clinical trials and longitudinal observational studies) the
9-item version (which is shorter and does not contain the last 3 items: embarrass-
ment and/or shame, social participation, and depression) is recommended. The
PsAID score provides information on each individual item as well as one overall
score. The PsAID score gives a number between 0 and 10. A higher score on the
PsAID indicates more impact of the disease. A score below 4 out of 10 is considered
U. Kiltz et al.