The English and Chinese versions of the five-level EuroQoL Group's five-dimension questionnaire (EQ-5D) were valid and reliable and provided comparable scores in Asian breast cancer patients.

OBJECTIVE: To examine the measurement properties of and comparability between the English and Chinese versions of the five-level EuroQoL Group's five-dimension questionnaire (EQ-5D) in breast cancer patients in Singapore. METHODS: This is an observational study of 269 patients. Known-group validity and responsiveness of the EQ-5D utility index and visual analog scale (VAS) were assessed in relation to various clinical characteristics and longitudinal change in performance status, respectively. Convergent and divergent validity was examined by correlation coefficients between the EQ-5D and a breast cancer-specific instrument. Test-retest reliability was evaluated. The two language versions were compared by multiple regression analyses. RESULTS: For both English and Chinese versions, the EQ-5D utility index and VAS demonstrated known-group validity and convergent and divergent validity, and presented sufficient test-retest reliability (intraclass correlation = 0.72 to 0.83). The English version was responsive to changes in performance status. The Chinese version was responsive to decline in performance status, but there was no conclusive evidence about its responsiveness to improvement in performance status. In the comparison analyses of the utility index and VAS between the two language versions, borderline results were obtained, and equivalence cannot be definitely confirmed. CONCLUSION: The five-level EQ-5D is valid, responsive, and reliable in assessing health outcome of breast cancer patients. The English and Chinese versions provide comparable measurement results.

Measurement properties of the eight-item abbreviated functional assessment of cancer therapy--breast symptom index and comparison with its 37-item parent measure.

CONTEXT: The Functional Assessment of Cancer Therapy--Breast Symptom Index (FBSI) is an eight-item instrument extracted from the Functional Assessment of Cancer Therapy--Breast (FACT-B). There has been no formal assessment of this eight-item version. OBJECTIVES: This study aimed to examine the measurement properties of and comparability between the English and the Chinese versions of the FBSI and to compare it with its parent instrument, the FACT-B, in breast cancer patients in Singapore. METHODS: This was an observational study of 271 breast cancer patients. Known-group validity of FBSI scores was assessed using four health indicators. Convergent and divergent validity was examined by correlation coefficients between the FBSI and the FACT-B. Responsiveness was assessed in relation to longitudinal changes in performance status. Test-retest reliability was evaluated by the intraclass correlation coefficient. Multiple regression analyses were performed to compare the scores on the two language versions. Receiver operating characteristic curve analyses were used for comparison between the FBSI and the FACT-B. RESULTS: For both language versions, the FBSI demonstrated known-group validity, convergent and divergent validity, and sufficient test-retest reliability (intraclass correlation coefficient = 0.75-0.77). The English version was responsive to changes in performance status. The Chinese version was responsive to decline in performance status, but there was no conclusive evidence about its responsiveness to improvement in performance status. No practical significant difference was found in the outcomes between the two language versions despite minor difference in one item. The FBSI performed comparably with the FACT-B. CONCLUSION: The English and Chinese versions of the FBSI are valid and reliable and provide comparable FBSI scores. The English version is responsive to change, whereas the responsiveness of the Chinese version warrants further study.

Comparison of the measurement properties between a short and generic instrument, the 5-level EuroQoL Group's 5-dimension (EQ-5D-5L) questionnaire, and a longer and disease-specific instrument, the Functional Assessment of Cancer Therapy-Breast (FACT-B), in Asian breast cancer patients.

PURPOSE: To compare the measurement precision and related properties between the 5-level EuroQoL Group's 5-dimension (EQ-5D-5L) questionnaire and the Functional Assessment of Cancer Therapy-Breast (FACT-B) questionnaire in assessing breast cancer patients. METHODS: An observational study of 269 Singaporean breast cancer patients. To compare discriminative ability and responsiveness, the effect sizes (in standard deviation) of the EQ-5D-5L and the FACT-B in relation to health indicators and the change in performance status or quality of life were estimated. Test-retest reliability was examined using the intraclass correlation (ICC). RESULTS: Using performance status, evidence of disease, and treatment status as the criteria, the differences (FACT-B minus EQ-5D-5L) in the effect size for discriminative ability were negative or closed to zero, and the 90% confidence intervals totally fell within the zone that indicated the non-inferiority of the EQ-5D-5L. For responsiveness and test-retest reliability, the confidence intervals of the differences in effect size and ICC overlapped the non-inferiority margin; thus, non-inferiority in these two aspects could neither be confirmed nor rejected. CONCLUSIONS: The EQ-5D-5L was non-inferior to the FACT-B in discriminating breast cancer patients with different health conditions cross-sectionally. The EQ-5D-5L serves as a reasonable alternative or supplementary instrument to the FACT-B in assessing breast cancer patients' health outcomes.