Psychometric Evaluation of the Brunei-Malay SF-36 version 2 Health Survey

OBJECTIVES: To culturally adapt the Short Form Health-36 version 2 (SF-36v2) into the Brunei-Malay context and determine its reliability and validity for measuring health-related quality of life (HRQOL) in healthy individuals and patients with chronic kidney disease in Brunei Darussalam. METHODS: An iterative multistep strategy involving setting up a bilingual expert panel, pretesting, text revision and back translation was used to prepare the Brunei-Malay SF-36v2 as an adaptation from the Malaysian-Malay SF-36v2. The Brunei-Malay SF-36v2 was then self-administered to a sample of healthy individuals (n=95) and predialysis chronic kidney disease outpatients (n=95) resident in Brunei. The mean (SD) age of the participants was 46.6 (17.8) years. RESULTS: Data completion rate was 100% with minimal floor effects (≤0.21) in all the 8 domains and >15% ceiling effects in 3 of the 8 domain scales. Cronbach’s alpha was >0.70 for all the 8 domain scales. Scaling success was 100% for convergent validity, with 100% item discriminant validity for all domain scales except Social Functioning (94%), Mental Health (85%) and General Health (85%). Principal component analysis of the two-factor dimension explained 68% overall variance and accounted for 81% reliable variance, but the exact SF-36 two-factor summary constructs in the standard algorithm were not replicated in the Bruneian population. CONCLUSIONS: The Brunei-Malay SF-36v2 is a valid and reliable instrument for measuring HRQOL in healthy individuals and patients with chronic kidney disease in Brunei. The summary scales should, however, be interpreted with caution. Further studies should be carried out to assess additional psychometric properties of the Brunei-Malay SF-36v2.