Validation of the scleroderma health assessment questionnaire and quality of life in English and Chinese-speaking patients with systemic sclerosis

Abstract

Aims

To perform cross-cultural adaptation and validation of the Scleroderma Health Assessment Questionnaire (S-HAQ) and Systemic Sclerosis Quality of Life scale (SSc-QoL) in English and Chinese-speaking patients with SSc.

Methods

In this Institutional Review Board approved study, patients seen at the rheumatology outpatient clinics were consecutively recruited over a 10-month period. We evaluated: (i) test–retest reliability using the intraclass correlation coefficient (ICC); (ii) known-groups construct validity by stratifying patients according to organ involvement and symptom severity; and (iii) convergent validity using Spearman's correlation with Short Form 36 version 2 (SF36v2).

Results

Forty-nine SSc patients completed the questionnaires: 26 Chinese, 23 English; 30 self-administered, 19 interviewer-administered, of which 35 responded to the retest. The SSc-QoL, HAQ Disability Index, intestinal Visual Analogue Scale (VAS), breathing VAS and overall disease severity VAS demonstrated high reliability (ICCs 0.71–0.93). The intestinal, finger ulcer and breathing S-HAQ VASs were able to differentiate patients according to their respective organ involvement. As hypothesized, the S-HAQ correlated better with the Physical Summary Component (PCS) than the Mental Summary Component (MCS) scores of the SF36v2. The SSc-QoL also demonstrated good convergent validity with the SF36v2 scales.

Conclusion

In this pilot study, we provided preliminary evidence to demonstrate the good test–retest reliability and reasonable construct validity of S-HAQ and SSc-QoL for use in English and Chinese-speaking SSc patients. This forms the basis for future studies to assess more extensively their psychometric properties.