Background The Psoriatic Arthritis Quality of Life (PsAQoL) questionnaire is a disease-specific, patient-derived instrument for assessing quality of life (QoL) in psoriatic arthritis (PsA).
Objectives The aim was to develop Singapore Chinese and English versions of the PsAQoL that were equivalent to, and met the same psychometric and acceptability standards as the original UK measure.
Methods Translation of the original questionnaire into Singapore Chinese and English was performed by professional and lay translation panels. Field-testing for face and content validity was performed by interviewing 10 Chinese speaking and 10 English speaking local patients respectively. Sixty-one consecutive PsA patients (either Chinese or English speaking) fulfilling the CASPAR criteria from a single tertiary centre were then invited to participate in a validation survey that included socio-demographic and clinical data. The clinical variables, Health Assessment Questionnaire (HAQ) and Medical Outcome Short form 36 (SF-36) were used as comparator instruments for evaluating convergent validity.
Results The validation sample included 70 patients (50.7% males), with a mean (SD) age of 52.5 (13.5) years. PsAQoL scores correlated with the HAQ (r=0.575, p<0.0001), SF-36 physical summary score (r=-0.423, p<0.0001), mental summary score (r=-0.547, p<0.0001) and clinical disease activities. The scale was able to distinguish between groups with active or inactive disease and with different levels of self-reported general health. Test–retest reliability over 2 weeks was good (ICC =0.934, P<0.0001).
Conclusions This study provides evidence that the adapted English and Chinese versions of PsAQoL can be used in clinical studies and for determining long-term outcomes in PsA patients in Singapore.
Disclosure of Interest None declared