Cross-Cultural Adaptation of the Systemic Lupus Erythematosus Quality of Life Questionnaire Into Chinese KOK OOI KONG, HSU JUANG HO, HWEE SIEW HOWE, BERNARD YU HOR THONG, TSUI YEE LIAN, HIOK HEE CHNG, AND KHAI PANG LEONG, FOR THE TAN TOCK SENG HOSPITAL SYSTEMIC LUPUS ERYTHEMATOSUS STUDY GROUP Objective. We have previously validated the English version of the Systemic Lupus Erythematosus Quality of Life Questionnaire (SLEQOL) in our patients with lupus. Many of our Chinese patients are not fluent in English and therefore a Chinese version (SLEQOL-C) has been adapted for their use. Methods. Two independent translators translated the SLEQOL into Chinese. A consensus version was derived from both sets of translations. Back translation of this version was performed by another 2 independent translators who had neither been involved in the forward translation nor encountered the SLEQOL. The final version, SLEQOL-C, was finalized after rectifying the discrepancies revealed by the back translation. Linguistic validity was tested in open interviews with bilingual patients with lupus. The SLEQOL-C and SLEQOL were administered to patients to determine whether they displayed differential item functioning (DIF). Results. In general, most of the items in English could be expressed in Chinese precisely, although a few instructions had to be altered slightly to make them more idiomatic. The forward and back translations of the SLEQOL were accomplished without major difficulties. A total of 638 patients were interviewed (62.8% with the SLEQOL and 37.2% with the SLEQOL-C). Using DIF analysis, there was no detectable test bias due to language use after controlling for repeated observations, age, sex, and ethnicity. Conclusion. The SLEQOL-C has semantic, idiomatic, and conceptual equivalence to the SLEQOL. The rigorous process of cross-cultural translation provides some measure of quality in the content validity. KEY WORDS. Cross-cultural adaptation; SLEQOL; Chinese; Quality of life; Systemic lupus erythematosus. INTRODUCTION Advances in medical care have greatly reduced mortality in systemic lupus erythematosus (SLE) (1). Consequently, improving the quality of life (QOL) of patients with SLE has become one of the major goals of modern therapy. To evaluate the success of treatment, a reliable instrument that measures QOL is needed. Over the last decade, health status instruments, such as QOL measures that encompass the physical, psychological, and emotional dimensions, have been used to assess the impact of SLE from the patient’s perspective. The Medical Outcomes Study 36- item Short Form Health Survey (SF-36) has been shown to be valid and reliable in measuring QOL in patients with SLE (2,3), although it has recently been found to be insen- sitive to change (4). Recently, our group developed an SLE-specific QOL scale in English (SLEQOL) and demon- strated its validity, reliability, and responsiveness to change (5,6). Although some of the general health measures, such as the SF-36 (2,3), the Health Assessment Questionnaire (7), and the abbreviated form of the World Health Organization Quality of Life instrument (8), have been translated and validated for Chinese-speaking patients, a validated SLE- specific QOL scale is not available in the Chinese language to date. We believe that the availability of such an instru- Supported by a research grant from Bio-Medical Research Council (01/1/28/18/016). Kok Ooi Kong, MRCP, Hsu Juang Ho, MSN, Hwee Siew Howe, M Med, Bernard Yu Hor Thong, MRCP, Tsui Yee Lian, MRCP, Hiok Hee Chng, FRCPG, Khai Pang Leong, FRCPE: Tan Tock Seng Hospital, Jalan Tan Tock Seng, Sin- gapore. Members of the Tan Tock Seng Hospital Systemic Lupus Erythematosus Study Group are shown in Appendix A. Address correspondence to Kok Ooi Kong, MRCP, Depart- ment of Rheumatology, Allergy and Immunology, Tan Tock Seng Hospital, 11, Jalan Tan Tock Seng, Singapore 308433. E-mail: Kok_Ooi_Kong@ttsh.com.sg. Submitted for publication November 22, 2006; accepted in revised form March 5, 2007. Arthritis & Rheumatism (Arthritis Care & Research) Vol. 57, No. 6, August 15, 2007, pp 980 –985 DOI 10.1002/art.22911 © 2007, American College of Rheumatology ORIGINAL ARTICLE 980