Development and evaluation of a quality of life measurement scale in English and Chinese for family caregivers of patients with advanced cancers.

BACKGROUND: The quality of life of family caregivers of patients with advanced cancers is an important concern in oncology care. Yet, there are few suitable measurement scales available for use in Asia. This study aims to develop and evaluate a locally derived measurement scale in English and Chinese to assess the quality of life of family caregivers of patients with advanced cancers in Singapore. METHODS: Scale contents were generated from qualitative research that solicited inputs from family caregivers. Six hundred and twelve family caregivers of patients with advanced cancers were recruited, of whom 304 and 308 chose to complete the English and Chinese versions of the quality of life scale, respectively. A follow-up survey was conducted for test-retest reliability assessment. Analyses began with pooling all observations, followed by analyses stratified by language samples and ethnic groups (among English-speaking participants). RESULTS: Factor analysis identified 5 domains of quality of life. The Root Mean Square Error of Approximation was 0.041 and Comparative Fit Index was 0.948. Convergent and divergent validity of the total and domain scores were demonstrated in terms of correlation with the Brief Assessment Scale for Caregiver and its sub-scales and a measure of financial concern; known-group validity was demonstrated in terms of differences between groups defined by patient's performance status. Internal consistency (Cronbach's alpha) of the total and domain scores ranged from 0.86 to 0.93. Test-retest reliability (intraclass correlation coefficient) ranged from 0.74 to 0.89. Separate analyses of the English- and Chinese-speaking samples and ethnic groups gave similar results. CONCLUSION: A new, validated, multi-domain quality of life measurement scale for caregivers of patients with advanced cancers that is developed with inputs from family caregivers is now available in two languages. We call this the Singapore Caregiver Quality Of Life Scale (SCQOLS).

Reference values for the short forms of the Singapore Caregiver Quality of Life Scale.

PURPOSE: The 15- and 10-item short forms of the Singapore Caregiver Quality of Life Scale (SCQOLS-15 and SCQOLS-10) were recently developed as a quick assessment of caregiver quality of life. Reference values describing the distribution of the total and domain scores are available for the full-length version, but they are not yet available for the short forms. This study aimed to estimate the reference values for the short forms. METHODS: Data from a cross-sectional survey of 612 family caregivers of patients with advanced cancer in Singapore were fitted in quantile regression models. Percentiles were estimated by regressing the short forms' scores on caregiver characteristics. Classification by the reference values for the short forms and the full-length version were compared and agreement was evaluated. RESULTS: The caregiver's role in caring for the patient and the patient's performance status were associated with the percentiles of the total scores and most domain scores (each Bonferroni-adjusted p-value, PB, < 0.05). Higher-educated caregivers were categorized into higher percentiles according to the SCQOLS-15 and SCQOLS-10 total scores and the SCQOLS-15 Mental Well-being and Financial Well-being domain scores (each PB < 0.05). Ethnicity was associated with the SCQOLS-15 Physical Well-being and Experience & Meaning domains (each PB < 0.05). The percentiles for the short forms showed moderate to substantial agreement with those for the full-length version in terms of classifying caregivers into percentile intervals (quadratic-weighted Kappa = 0.72 to 0.92). CONCLUSION: Reference values for the SCQOLS-15 and SCQOLS-10 were estimated in relation to caregiver characteristics to facilitate interpretation of the short form scores.

Development of a short form of the Singapore Caregiver Quality of Life Scale - Dementia: SCQOLS-D-15.

PURPOSE: The Singapore Caregiver Quality of Life Scale - Dementia (SCQOLS-D), developed based on the Singapore Caregiver Quality of Life Scale (SCQOLS), comprises 5 domains and 63 items. It has been shown to be a valid and reliable measurement scale. This study aimed to develop and evaluate a short form of the SCQOLS-D. METHODS: Data were collected from 102 family caregivers of person with dementia in Singapore. Candidate items were shortlisted by factor analysis, correlation and best subset regression. Shortlisted items with the best measurement properties including correlations with the long form and other established measures, internal consistency and test-retest reliability were identified. Their properties were compared with the corresponding domain scores in the long form of SCQOLS-D and a short form of the SCQOLS. A total score based on the average of the domain scores was also evaluated. RESULTS: A total of fifteen items, two to four items per domain, were selected. The total and domain scores generated from these items strongly correlated with the corresponding score of the long form (correlation coefficients: 0.83-0.97). The short and long forms had comparable correlation coefficients with Negative Personal Impact and Positive Personal Impact measures. The short form showed good internal consistency (Cronbach's alpha: 0.84-0.92) and test-retest reliability (intra-class correlation coefficient: 0.72-0.93). These 15 items form the SCQOLS-D-15, an abbreviated version of the SCQOLS-D. CONCLUSION: The SCQOLS-D-15 showed acceptable measurement properties. This serves as an alternative to the SCQOLS-D to provide rapid assessment of the overall and domain-specific quality of life of caregivers of persons with dementia.

Development and evaluation of the Singapore Caregiver Quality of Life Scale - Dementia.

PURPOSE: To develop and evaluate a measurement scale for multi-domain assessment of the quality of life of family caregivers of persons with dementia (PWD) in Singapore, a multi-ethic society in South-East Asia where English is the lingua franca. METHODS: Items from the Singapore Caregiver Quality of Life Scale (SCQOLS), which was originally developed in the context of advanced cancers, were adopted as candidate items. Furthermore, a multi-disciplinary panel reviewed dementia-specific caregiver quality of life scales to identified items not covered in SCQOLS for inclusion as candidate items. A pilot study of 31 family caregivers of PWD was conducted to solicit inputs on candidate items; 102 family caregivers of PWD were surveyed for evaluation of the scale's measurement properties. RESULTS: Factor analysis confirmed a 5-domain structure of the 63 candidate items. The Root Mean Square Error of Approximation was 0.056 and Comparative Fit Index was 0.928. Convergent validity of the total and domain scores was demonstrated in terms of correlation with the Brief Assessment Scale for Caregivers and its sub-scales. The scores also showed an expected pattern of correlation with hours spent on caregiving per week. Known-group validity was demonstrated by differences in mean scores between functional staging groups. Cronbach's alpha of the total and domain scores ranged from 0.89 to 0.95. Test-retest reliability (intraclass correlation coefficient) ranged from 0.77 to 0.92. CONCLUSIONS: The Singapore Caregiver Quality of Life Scale - Dementia (SCQOLS-D) is a quality of life measurement scale for family caregivers of persons with dementia that is valid and reliable.

Two valid and reliable short forms of the Singapore caregiver quality of life scale were developed: SCQOLS-10 and SCQOLS-15.

OBJECTIVES: The Singapore Caregiver Quality of Life Scale (SCQOLS) comprises five domains and 51 items in total. This study aimed to develop and evaluate short forms of SCQOLS. STUDY DESIGN AND SETTING: Data were collected from 612 family caregivers of patients with advanced cancers in Singapore. Exploratory factor analysis and best subset regression were used to identify candidate items for each domain. The short forms were evaluated for measurement properties. RESULTS: Inclusion of at least two items per domain in the short form gave correlation coefficients of at least 0.8 with the corresponding domain scores in the full-length version. The short forms and full-length version had similar correlation coefficients with Negative Personal Impact and Positive Personal Impact measures. Two of the five domains of the 10-item version had Cronbach's alpha ≤0.50 and test-retest reliability ≤0.65. A 15-item version of the scale with two to four items per domain performed satisfactorily in all aspects evaluated. CONCLUSION: A 15-item short form of the SCQOLS (SCQOLS-15) is valid and reliable for the assessment of the overall and domain-specific quality of life of family caregivers. A 10-item short form (SCQOLS-10) may serve as a quick, valid and reliable assessment of the overall level of quality of life.

Reference values for and interpretation of the Singapore Caregiver Quality of Life Scale: a quantile regression approach.

PURPOSE: The Singapore Caregiver Quality of Life Scale (SCQOLS) was recently developed and validated in two languages - English and Chinese. The total and domain scores are scaled to range from 0 to 100. However, the scale is not at the interval-ratio level of measurement. To facilitate interpretation, we established the percentiles of the scale's total and domain scores among family caregivers of patients with advanced cancers and demonstrate the effect size in terms of differences in relation to caregiver and patient characteristics. METHODS: Data were drawn from a cross-sectional survey of family caregivers of patients with stage III or IV solid cancers in Singapore. Quantile regression was used to estimate the percentiles in relation to caregiver and patient characteristics. RESULTS: Participants in adjacent categories of patient's performance status and caregiver's having other family members to share caregiving duties differed by 3 to 5 points in median quality of life total score and most domain scores (each Bonferroni-adjusted P, P[B], < 0.05). Ethnicity was associated with the Physical Well-being and Experience & Meaning domain scores (each P[B] < 0.05), with variable direction and magnitude. Education was associated with Mental Well-being and Financial Well-being (each P[B] < 0.05). Equations and examples for calculation of the percentiles are provided. CONCLUSION: Percentiles and effect size estimates are provided to facilitate interpretation of the SCQOLS.