Adaptation of Chinese and English versions of the Psoriatic Arthritis Quality of Life (PsAQoL) scale for use in Singapore.

Ying Ying Leung,Julian Thumboo,Stephen P Mckenna,Matthew Rouse

doi:10.1186/s12891-016-1292-4

Abstract

BackgroundTo develop Singapore Chinese and English versions of the Psoriatic Arthritis Quality of Life (PsAQoL) scale that were equivalent to and met the same psychometric and acceptability standards as the original UK measure.MethodsTranslation of the original PsAQoL into contextualised English and Chinese versions for use in Singapore was performed by professional and lay translation panels. Ten Chinese speaking and ten English speaking local patients were interviewed to assess face and content validity. Psoriatic arthritis (PsA) patients (either Chinese or English speaking) fulfilling the Classification criteria of Psoriatic Arthritis were then invited to participate in a validation survey. Clinical variables, the Health Assessment Questionnaire (HAQ) and the Medical Outcome Short-form 36 (SF-36) were used as comparator instruments for convergent validity. A separate sample of PsA patients were invited to participate in a test-retest postal study, with two weeks between administrations.ResultsThe validation sample included 98 patients (51 % men) with a mean (SD) age of 51.5 (13.8) years. The PsAQoL had excellent internal consistency (Cronbach’s α = 0.92) and scores on the measure were moderately correlated with health status measures (pain, HAQ score, SF-36 scores) and patient and physician global assessments. The scale was able to distinguish between groups with active or inactive disease assessed by composite scores, HAQ and minimal disease activity. Test–retest reliability was excellent (r = 0.92).ConclusionsThis study provides evidence that the adapted English and Chinese versions of the PsAQoL can be used in clinical studies with PsA patients in Singapore.

Highlights

To develop Singapore Chinese and English versions of the Psoriatic Arthritis Quality of Life (PsAQoL) scale that were equivalent to and met the same psychometric and acceptability standards as the original United Kingdom (UK) measure
Translation of the PsAQoL The PsAQoL was translated into Singapore Chinese and English using the dual-panel methodology, which is used in the adaptation of new language versions of all needsbased quality of life (QoL) measures [21]
As the original PsAQoL is in English, only a lay panel was necessary for the Singapore English adaptation, to ensure that the wording of the items was appropriate for local patients

Summary

Introduction

To develop Singapore Chinese and English versions of the Psoriatic Arthritis Quality of Life (PsAQoL) scale that were equivalent to and met the same psychometric and acceptability standards as the original UK measure. A number of measures have been used to assess patient-reported outcomes (PROs) in PsA. Most of these focus on the symptoms and functional limitations. The Psoriatic Arthritis Quality of Life (PsAQoL) scale was the first patient-derived disease-specific instrument for measuring outcome in PsA [14]. It complies with the US Food and Drug Administration (FDA) recommendation of using inputs elicited from patients to support labeling claims [15].

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