Validity of a Revised Short Form-12 Health Survey Version 2 in Different Ethnic Populations

<p><b>INTRODUCTION</b>The Short Form-12 version 2 (SF-12v2) is a shorter version of the Short Form-36 version 2 (SF-36v2) for assessing health-related quality of life. As the SF-12v2 could not be resolved into the physical- and mental-component summary score (PCS and MCS, respectively) in the general population of Singapore, this study aims to determine and validate the Singapore SF-12 version 2 (SG-12v2).</p><p><b>MATERIALS AND METHODS</b>The SG- 12v2 was generated using the same methodology as the SF-12v2. Bootstrap analysis was used to determine if the SG-12v2 were significantly different from the SF-12v2. Content validity was assessed using percentage of variance (R²) of the Singapore version of SF-36v2 PCS and MCS explained by the SG-12v2 items. Agreement between the SF-36v2 and the SG-12v2 was assessed using Bland-Altman diagrams. Criterion validity was demonstrated if effect size differences between SF-36v2 and SG-12v2 were small (Cohen's criteria). Known-group validity of SG-12v2 was reported for participants with and without chronic diseases.</p><p><b>RESULTS</b>Five items differed between the SG-12v2 and SF-12v2. Bootstrap analysis confirmed that SG-12v2 and SF-12v2 were significantly different. The SG12v2 explained 94% and 79% of the R² of the SF-36v2 PCS and MCS, respectively. Agreement was good and effect size differences were small (<0.3). Participants with chronic diseases reported lower SG-12v2 scores compared to participants without chronic diseases.</p><p><b>CONCLUSION</b>The SG-12v2 offers advantage over the SF-12v2 for use in the general population of Singapore. The SG-12v2 is a valid measure and will be particularly useful for large population health surveys in Singapore.</p>

Diabetes Health Profile-18 is Reliable, Valid and Sensitive in Singapore

<p><b>INTRODUCTION</b>The Diabetes Health Profile-18 (DHP-18) measures diabetes-related psychological well-being in patients with type 2 diabetes mellitus (T2DM). It includes 3 subscales: psychological distress (PD), barriers to activity and disinhibited eating. The psychometric properties of the DHP have not been evaluated in Asia. The aim of this study was to determine the psychometric properties of the DHP in multiethnic Singapore.</p><p><b>MATERIALS AND METHODS</b>Patients between the ages of 18 to 65 diagnosed with diabetes (either type 1 or type 2) for at least 1 year were recruited from a diabetes outpatient clinic in a tertiary hospital. They completed a set of self-administered questionnaires including sociodemographic information and the DHP. Validity of the DHP was evaluated using confirmatory factor analysis (CFA) and exploratory factor analysis (EFA). Reliability was assessed with internal consistency and sensitivity was determined by effect size, associated with detecting a statistically significant and clinically important difference between various patient subgroups.</p><p><b>RESULTS</b>A total of 204 patients with mean age 45.4 (11.9) years, comprising 64% males and 50% Chinese, 27% Indian and 12% Malay were studied. In CFA, model fit was poor. Forced 3-factor EFA supported the original 3-factor structure of the DHP. Convergent and discriminant validity was demonstrated (100% scaling success). DHP was sensitive across majority of social demographic, clinical and social-functioning determinants (i.e., effect size >0.3). Cronbach's alpha exceeded 0.70 for all subscales. Ceiling effects were negligible but large floor effects were seen for the PD subscale (23%).</p><p><b>CONCLUSION</b>The DHP is valid, reliable and sensitive for measuring well-being in Asian patients with T2DM.</p>

WHOQOL-BREF among Singaporean Patients with Type II Diabetes Mellitus: What Does It Measure.

Aims: Health-related quality of life (HRQoL) of Type 2 diabetes mellitus (T2DM) is a growing concern globally given the increase in T2DM prevalence. Generic HRQoL instruments are important to allow cross-cultural, cross-population and cross-study comparisons. The short version of the World Health Organization Quality of Life (WHOQOL-BREF) questionnaire is a widely used generic questionnaire. Hence, we aimed to evaluate the psychometric properties of the WHOQOL-BREF among patients with T2DM in Singapore. Study Design: Patients at a diabetes outpatient specialist clinic in Singapore were recruited via convenience sampling. Classical Test Theory methods were used to evaluate data quality, scaling assumptions, targeting, internal consistency reliability and construct validity (structural, convergent and discriminant) and criterion validity using HbA1c control (good versus poor). Principal Component Analyses (PCA) and Confirmatory Factory Analyses (CFA) were performed to assess unidimensionality (domain-level) as well as conformity with the original four-factor structure. Exploratory Factor Analysis (EFA) was done if CFA indicated lack of fit. Results: 212 subjects were analyzed of whom 50% were Chinese, 28% Indians, 11% Malays and 10% others. 63% were males with mean (SD) age 45.8 (11.9) years. Data quality was superior, scaling assumptions were met, targeting was satisfactory and internal consistency was achieved. PCAs were compatible with unidimensionality, except in the Physical domain. Domain level CFA indicated that unidimensionality had poor fit and overall CFA did not support the original 4-factor structure. EFA runs showed that the Physical and Environment domains overlapped while the Social and Psychological domains could not be recovered. Therefore construct (structural) validity was not established. Criterion validity was not achieved as all domains could not discriminate between those with good versus poor HbA1c control. Conclusion: Construct and criterion validity of WHOQOL-BREF posed some concerns. Thus, we recommend that an adequately-powered random sample of T2DM patients in Singapore be studied to confirm the findings of our study.

Normative Data for the Singapore English and Chinese SF-36 Version 2 Health Survey

<p><b>INTRODUCTION</b>The aim of this study is to report normative data for the Short-Form 36 version 2 (SF-36v2) for assessing health-related quality of life, in the Singapore general population.</p><p><b>MATERIALS AND METHODS</b>Data for English and Chinese-speaking participants of the Singapore Prospective Study Programme were analysed. The SF-36v2 scores were norm-based with the English-speaking Singapore general population as reference and reported by age (in decades), gender and ethnicity as well as for the 5 most prevalent chronic medical conditions. Scores were reported separately for the English and Chinese language versions.</p><p><b>RESULTS</b>A total of 6151 English-speaking (61.5% Chinese and 19.2% Malay) and 1194 Chinese-speaking participants provided complete data. Mean (SD) age of all participants was 49.6 (12.58) years with 52.4% being women. In both languages, women reported lower scores than men on all scales. Among the chronic medical conditions, stroke had the largest impact on all English SF-36v2 scales and on 3 Chinese SF-36v2 scales (role-physical, general health and social functioning).</p><p><b>CONCLUSION</b>We have provided detailed normative data for the Singapore English and Chinese SF-36v2, which would be valuable in furthering HRQoL research in Singapore and possibly the region.</p>

Prevalence and control of hypercholesterolaemia as defined by NCEP-ATPIII guidelines and predictors of LDL-C goal attainment in a multi-ethnic Asian population

<p><b>INTRODUCTION</b>Few studies in Asia have assessed the burden of hypercholesterolaemia based on the global cardiovascular risk assessment. This study determines the burden of hypercholesterolaemia in an Asian population based on the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATPIII) guidelines, and examines predictors of low-density lipoprotein cholesterol (LDL-C) goal attainment.</p><p><b>MATERIALS AND METHODS</b>Five thousand and eighty-three Chinese, Malays and Asian-Indians living in Singapore were assigned to coronary heart disease (CHD)-risk category based on the NCEP-ATPIII guidelines. Awareness, treatment and control of hypercholesterolaemia based on risk- specific LDL-C goal were determined, including the use of lipid-lowering therapy (LLT). Cox-regression models were used to identify predictors of LDL-C above goal among those who were aware and unaware of hypercholesterolaemia.</p><p><b>RESULTS</b>One thousand five hundred and sixty-eight (30.8%) participants were aware of hypercholesterolaemia and 877 (17.3%) were newly diagnosed (unaware). For those who were aware, 39.3% participants received LLT. Among those with 2 risk factors, only 59.7% attained LDL-C goal. The majority of them were taking statin monotherapy, and the median dose of statins was similar across all CHD risk categories. Among participants with 2 risk factors and not receiving LLT, 34.1% would require LLT. Malays or Asian-Indians, higher CHD risk category, increasing body mass index (BMI), current smoking and lower education status were associated with higher risk of LDL-C above goal. Being on LLT reduced the risk of having LDL-C above goal.</p><p><b>CONCLUSION</b>The burden of hypercholesterolaemia is high in this multi-ethnic population especially those in the higher CHD risk categories, and might be partly contributed by inadequate titration of statins therapy. Raising awareness of hypercholesterolaemia, appropriate LLT initiation and titration, weight management and smoking cessation may improve LDL-C goal attainment in this population.</p>