Validity and reliability of the EQ-5D self-report questionnaire in Chinese-speaking patients with rheumatic diseases in Singapore.

OBJECTIVE: We assessed the psychometric properties of a Singaporean Chinese version of the EQ-5D, a health-related quality of life (HRQoL) instrument. MATERIALS AND METHODS: Consecutive outpatients with rheumatic diseases seen for routine follow-up consultations at the National University Hospital, Singapore were interviewed twice within 2 weeks using a standardised questionnaire containing the EQ-5D, the Short-Form 36 Health Survey (SF-36), the Learned Helplessness Subscale, a pain Visual Analogue Scale (VAS) and assessing demographic and psychosocial characteristics. To assess the validity of the EQ-5D, 13 hypotheses relating the EQ-5D self-classifier (5 dimensions) or visual analogue scale (EQ-VAS) to SF-36 scores or other variables were examined using the Mann-Whitney U test, Kruskal-Wallis or Spearman's correlation coefficient. Test-retest reliability was assessed using Cohen's kappa. RESULTS: Forty-eight subjects were studied (osteoarthritis: 16; rheumatoid arthritis: 22; systemic lupus erythematosus: 8; spondyloarthropathy: 2; female: 93.8%; mean age: 56.4 years). Seven of 13 a-priori hypotheses relating EQ-5D to external variables were fulfilled, supporting the validity of the EQ-5D. For example, subjects reporting moderate or extreme problems for EQ-5D dimensions generally had lower median SF-36 scores than those without such problems. Cohen's kappa for test-retest reliability of the self-classifier ranged from 0.41 to 1.00 (n = 42; median interval: 7 days, interquartile range: 7 to 11 days). CONCLUSIONS: The Singaporean Chinese EQ-5D self-classifier appears to be a valid measure of HRQoL in Singaporeans with rheumatic diseases; however, the reliability of the EQ-VAS requires further investigation. These data provide a basis for further studies of the Singaporean Chinese EQ-5D.

Validation of the Western Ontario and Mcmaster University osteoarthritis index in Asians with osteoarthritis in Singapore.

OBJECTIVE: To assess the reliability and validity of the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) as an outcome measure in Asian patients with knee or hip osteoarthritis (OA) in Singapore. DESIGN: The WOMAC was administered twice 7 days apart to 66 consecutive English-speaking Chinese, Malay or Indian inpatients and outpatients with knee or hip OA seen at a tertiary referral centre through a structured interview, which also assessed demographic and other characteristics. Internal consistency was assessed using Cronbach's alpha, reliability using Spearman's correlations, intraclass correlations and repeatability coefficients, and relationships between WOMAC domains and known determinants of function using Spearman's correlations and the Mann-Whitney U-test. RESULTS: The WOMAC showed good internal consistency (alpha=0.70 to 0.93) and good reliability, with intraclass correlations of 0.83 to 0.90 and mean test-retest score differences of 0.02 to 0.13 points (possible range 4 points). Results of Likert scoring assessment supported the validity of the WOMAC when interpreted in the context of the close association between pain and physical function. Eight of nine a priori hypotheses relating WOMAC Pain and Physical Function scores to known determinants of function were present, supporting construct validity of this scale. CONCLUSION: The WOMAC is a valid and reliable outcome measure in Asian patients with OA in Singapore.

Socioeconomic and psychosocial factors influence pain or physical function in Asian patients with knee or hip osteoarthritis.

OBJECTIVE: To determine factors influencing pain or physical function in Asian patients with osteoarthritis (OA). METHODS: 126 consecutive Chinese (110), Malays (two), Indians (10), or other races (four) with knee or hip OA and a median age of 60.5 years were seen at a tertiary referral centre; 103 were women. Subjects underwent a structured assessment including the Short Form-36 (SF-36) bodily pain (BP) and physical functioning (PF) scales and assessing demographic, socioeconomic, psychosocial, and other characteristics. Factors influencing BP or PF were identified using separate multiple linear regression models. RESULTS: The index joint (that is, the most symptomatic joint) was the knee in 118 (94%) and the hip in eight (6%) patients. The median duration of pain and limitation of normal activities were three years and one year, respectively. The mean BP and PF scores of 57.7 and 56.2 points for the patients were substantially lower than the expected scores of 79.3 and 80.8 points for the general Singapore population. Multiple regression analysis showed that less pain was associated with a younger age, shorter duration of symptoms, more years of education, working, and Chinese ethnicity. Better physical function was associated with more years of education, less learned helplessness, less bodily pain, and less severe OA. CONCLUSIONS: Socioeconomic status and psychosocial factors, some of which are potentially modifiable, influence pain or physical function in Asian patients with OA in Singapore.

Validity and reliability of the EQ-5D self-report questionnaire in English-speaking Asian patients with rheumatic diseases in Singapore.

Validity and reliability of a Singaporean English EQ-5D self-report questionnaire (EQ-5D) were evaluated among consecutive outpatients with rheumatic diseases attending a tertiary referral hospital in Singapore (a multi-ethnic, urban Asian country). Subjects were interviewed twice within a 2-week period using a standardized questionnaire containing the EQ-5D, Short Form 36 Health Survey (SF-36) and assessing demographic and psychosocial characteristics. To assess validity of the EQ-5D, 13 hypotheses relating responses to EQ-5D dimension/Visual Analogue Scale (EQ-VAS) to SF-36 scores or other variables were examined using the Mann-Whitney test, Kruskal-Wallis test, or Spearman's correlation coefficient. Test-retest reliability was assessed using Cohen's kappa. Sixty-six subjects were studied (osteoarthritis: 9, rheumatoid arthritis: 26, systemic lupus erythematosus: 23, spondyloarthropathy: 8; female: 72.7%; mean age: 44.3 years). Ten of 13 a-priori hypotheses relating EQ-5D responses to external variables were fulfilled, supporting the validity of the EQ-SD. Cohen's kappa for test-retest reliability (n = 52) ranged from 0.29 to 0.61. The Singaporean English EQ-5D appears to be valid in measuring quality of life in Singaporeans with rheumatic diseases; however, its reliability requires further investigation. These data provide a basis for further studies assessing the validity of the EQ-5D in Singapore.