Cynthia Goh

Variability and Sample Size Requirements of Quality-of-Life Measures: A Randomized Study of Three Major Questionnaires

PURPOSE To compare the variability and sample size requirements of the global quality-of-life (QOL) scores of the following three major QOL instruments: the Functional Assessment of Cancer Therapy-General (FACT-G), Functional Living Index-Cancer (FLIC), and European Organisation for Research and Treatment of Cancer Core Quality of Life Questionnaire C30 (EORTC QLQ-C30). PATIENTS AND METHODS Cancer patients were randomly assigned to answer two of the three instruments using an incomplete block design (n = 1,268). The instruments were compared in terms of coefficient of variation, effect size in detecting a difference between patients with different performance status, and correlation coefficient between scores at baseline and follow-up. RESULTS The FACT-G and FLIC had significantly smaller coefficients of variation than the EORTC QLQ-C30 (both P < .05). The FLIC also had significantly larger correlation coefficients between scores at baseline and follow-up than the EORTC QLQ-C30 (P < .05). The FACT-G and the FLIC had a larger effect size in a cross-sectional and longitudinal setting, respectively, than the EORTC QLQ-C30 in differentiating patients with different performance status (both P < .05). CONCLUSION In some aspects, the FACT-G and FLIC global QOL scores had smaller variability and larger discriminative ability than the EORTC QLQ-C30. Further research using other criteria to compare the three instruments is recommended.

Mapping the English and Chinese Versions of the Functional Assessment of Cancer Therapy-General to the EQ-5D Utility Index

OBJECTIVE This study aims to develop a function for mapping the English and Chinese versions of the Functional Assessment of Cancer Therapy-General (FACT-G) scores to the EuroQoL Groups EQ-5D utility index and to test whether a single function is sufficient for the two language versions. METHODS A baseline survey of 558 cancer patients in Singapore using the FACT-G and EQ-5D was conducted (308 English and 250 Chinese questionnaires). Regression models were used to predict the EQ-5D utility index values based on the FACT-G scores and thus derive a mapping equation. Data from a follow-up survey of the patients were used to validate the results. RESULTS The FACT-G Social/Family scale was not associated with the EQ-5D utility index (P = 0.701). There was no interaction between language version and the predictors (each P > 0.1). An equation that maps the FACT-G Physical, Emotional, and Functional well-being scales to the EQ-5D utility index was derived. In the validation sample, the mean observed utility values was larger than the mapped by only 0.005 (95% confidence interval [CI]-0.006 to 0.016), but the mean absolute difference was 0.083 (95% CI 0.076 to 0.090). CONCLUSIONS At the group level, but not individual level, the equation developed can accurately map the English and Chinese versions of the FACT-G scores to the EQ-5D utility index.

The equivalence and difference between the English and Chinese versions of two major, cancer‐specific, health‐related quality‐of‐life questionnaires

English and Chinese are two of the most widely used primary languages in the world. Patients in many cancer centers have a variety of ethnic backgrounds and primary languages. The comparability of version 4 of the English and Chinese versions of the Functional Assessment of Cancer Therapy‐General (FACT‐G) and version 3 of the European Organization for the Research and Treatment of Cancer Core Quality of Life Questionnaire (EORTC QLQ‐C30) have not been established.

The Singaporean English and Chinese versions of the EQ-5D achieved measurement equivalence in cancer patients.

OBJECTIVE To assess measurement equivalence of the Singaporean English and Chinese versions of the EuroQol Groups 5-domain questionnaire (EQ-5D) in cancer patients. STUDY DESIGN AND SETTING Seven hundred and seventy-one ethnic Chinese patients in Singapore were recruited, and they answered either an English or a Chinese version of the EQ-5D. Seven days later, a similar questionnaire in the same language was mailed to the patients. Regression analysis was used to assess equivalence of the mean values obtained by using the two language versions. The validity, responsiveness to change, and reliability of the two versions of the EQ-5D were assessed and compared. RESULTS Based on the prespecified equivalence margin of +/-10% for binary outcome, +/-0.05 for utility index, and +/-5 points in the visual analog scale, the two language versions of the EQ-5D gave equivalent mean values at item and scale levels. They also showed similar characteristics in validity, responsiveness, and reliability. For example, the test-retest reliability values for the EQ-5D utility index in the two language samples were identical in two significant digits: 0.79. CONCLUSION The Singaporean English and Chinese versions of the EQ-5D were validated in cancer patients and were shown to achieve measurement equivalence.

Order effects in the assessment of quality of life in cancer patients

Methodological studies and outcome research often include several health-related quality of life (HRQoL) measurement scales in one questionnaire. Psychological studies have previously demonstrated that changing the sequential order of measurement scales within a questionnaire can alter the pattern of responses. Little is known, however, about whether there are order effects on the assessment of HRQoL in cancer patients. Here we address this issue in a study of 190 Singaporean cancer patients who were assessed using two different HRQoL instruments placed in alternating sequence within a questionnaire package. Measurement properties of the instruments, including the number of missing values, means, variability, known-group validity and internal consistency, were compared in the two samples representing different presentation orders. The HRQoL instruments administered in different sequential orders appeared to be equivalent in several aspects. No major effect of presentation order on outcomes was shown. The reasons and implications of the absence of an order effect are discussed. We conclude that presentation order is unlikely to alter the responses to the two HRQoL instruments.

Where the Elderly Die: The Influence of Socio-Demographic Factors and Cause of Death on People Dying at Home

INTRODUCTION The place of death of the elderly has implications on the overall healthcare delivery system. The aim of this study is to describe where deaths of elderly occur in Singapore and to determine the association of socio-demographic characteristics and the causes of death on dying at home. MATERIALS AND METHODS Data of 10,399 Singapore resident decedents aged 65 years and above in 2006 were obtained from the national Registry of Births and Deaths. Distributions of socio-demographic characteristics and causes of death by place of death were analysed, and associations between socio-demographic characteristics and home death for major causes of death were assessed by logistic regression models controlling for age, gender and ethnic group. RESULTS Most elderly deaths occurred in hospitals (57%), followed by deaths at home (31%). The proportion of deaths at home increased with age while deaths in hospital declined with age. Significantly more elderly women died at home compared to men. Malay elderly had the highest proportion of home deaths (49%), and the lowest proportion of hospital deaths (47%). Elderly persons who died from stroke were most likely to die at home [odds ratio (OR) 2.8, 95% confidence interval (CI), 2.3-3.3] while those who died from lung and respiratory system diseases were less likely to die at home (OR, 0.7; 95% CI, 0.6-0.8). CONCLUSION Elderly people in Singapore die mainly in hospitals. About a third of them die at home. The proportion of decedents dying at home increased with age. Home deaths among the elderly are most likely in those aged 85 years and above, females, Malays, and those who die of stroke.

The Lymphotoxin-α (LTα) Subunit Is Essential for the Assembly, but Not for the Receptor Specificity, of the Membrane-anchored LTα1β2 Heterotrimeric Ligand

The lymphotoxins (LT) α and β, members of the tumor necrosis factor (TNF) cytokine superfamily, are implicated as important regulators and developmental factors for the immune system. LTα is secreted as a homotrimer and signals through two TNF receptors of 55–60 kDa (TNFR60) or 75–80 kDa (TNFR80). LTα also assembles with LTβ into a membrane-anchored, heterotrimeric LTα1β2 complex that engages a distinct cognate receptor, the LTβ receptor (LTβR). To investigate the role of the LTα subunit in the function of the membrane LTα1β2 complex, gene transfer via baculovirus was used to assemble LTα and -β complexes in insect cells. LTα containing mutations at D50N or Y108F are secreted as homotrimers that fail to bind either TNF receptor and are functionally inactive in triggering cell death of the HT29 adenocarcinoma cell line. In contrast, these mutant LTα proteins retain the ability to co-assemble with LTβ into membrane-anchored LTα1β2 complexes that engage the LTβR and trigger the death of HT29 cells. Membrane-anchored LTβ expressed on the cell surface in absence of the LTα subunit binds the LTβR but is functionally inactive in the cell death assay. These results indicate that the TNF receptor-binding regions of the LTα subunit are not necessary for engagement of the LTβR, but the LTα subunit is required for the assembly of LTβ into a functional heteromeric ligand.

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

ObjectiveTo 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.MethodsThis 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.ResultsFor 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.ConclusionThe 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.

What do renal health-care professionals in Singapore think of advance care planning for patients with end-stage renal disease?

Aim:  Previous studies have focused either on advance medical directives rather than advance care planning (ACP), or on patients perspectives on ACP rather than those of the health‐care providers. This study aimed to explore the knowledge, attitudes and experience of renal health‐care professionals in Singapore on ACP for patients with end‐stage renal failure.

Quick-FLIC: validation of a short questionnaire for assessing quality of life of cancer patients

A practically useful measure of quality of life should be simple and quick to complete. A shortened Chinese version of the Functional Living Index – Cancer (FLIC) was recently proposed and was called Quick-FLIC. This study aims to assess the measurement properties of the Quick-FLIC. A total of 190 patients who received care from the National Cancer Centre of Singapore completed a questionnaire package at baseline. Patients filled in a retest questionnaire on average 2 weeks after baseline to assess test–retest reliability and responsiveness to change. The Quick-FLIC scores correlated well with the Functional Assessment of Chronic Therapy – General scores (r=0.78). Patients with different treatment status, performance status and self-rated health had significantly different Quick-FLIC scores in the expected directions (ANOVA; each P<0.001). Internal consistency (Cronbachs alpha=0.87) and 2-week test–retest reliability (intraclass correlation=0.81) were also satisfactory. The measure was responsive to changes in health status (P<0.001). The Quick-FLIC is a valid and reliable measure of health-related quality of life of cancer patients. The shortening of established health-related quality of life instruments should be considered in order to reduce the burden of having patients to answer lengthy questionnaires.