Quantifying health-related quality of life in Malaysian type 2 diabetes: focusing on complication types and severity.

PURPOSE: There is a knowledge gap of health utility values for Type 2 Diabetes Mellitus (T2DM) complications in Malaysia. This study aimed to estimate EQ-5D-5L utility values and evaluate health-related quality of life (HRQoL) for Malaysian T2DM associated with complications and clinical characteristics. METHODS: A cross-sectional study was conducted on T2DM patients at a tertiary hospital outpatient using the Malay and English version of the EQ-5D-5L questionnaire. Health utility values were derived using the Malaysian EQ-5D-5L value set. Ordinary least squares (OLS) multivariable regression model was used to estimate the health utility decrements associated with T2DM-related complications and clinical characteristics. RESULTS: A total of 513 T2DM patients were recruited. Overall, pain was the most affected of all five EQ-5D-5L dimensions. Patients with foot ulcer, amputation, severe heart failure and frequent hypoglycemia reported more problems collectively in all EQ-5D-5L dimensions. Older age, lower education level, longer duration of T2DM, urine protein creatine index (UPCI) > 0.02 g/mmol, and injection therapy were significantly associated with lower EQ-5D-5L utility values (p < 0.004, Bonferroni adjusted). The lowest unadjusted utility values were reported for severe heart failure 0.65 (interquartile range, IQR 0.50), frequent hypoglycemia 0.74 (0.22) and being amputated 0.78 (0.47). In the multivariable regression model after controlling for sociodemographic and clinical characteristics, the largest utility value decrement was observed for amputation (- 0.158, SE 0.087, p = 0.05), frequent hypoglycemia (- 0.101, SE 0.030, p = 0.001), myocardial infarction (-0.050, SE 0.022, p = 0.022) and obesity (-0.034, SE 0.016, p = 0.029). CONCLUSION: Larger utility value decrements were found for severe stages of complications. These findings suggest the value of defining severity of complications in utility elicitation studies. The utility decrement quantified for different T2DM complication severity will be useful for economic evaluations within diabetic-related fields.

Perspectives of the public on the consumption of unregistered health products in Malaysia.

OBJECTIVE: Unregistered medications which are lacking regulation in terms of safety, efficacy and quality may cause unpredictable adverse drug reactions (ADRs) in consumers. Therefore, this study aimed to assess the public knowledge, attitude and practice of consuming and purchasing unregistered health products in Malaysia. METHODS: A cross-sectional study involving members of the Malaysian public was carried out using the convenience sampling method. Descriptive statistics were used to summarise the socio-demographic characteristics of the respondents. Associations between knowledge items/scores and other items were assessed using Spearman's rank correlations and Cramer's V. Regression analyses were carried out to determine whether the socio-demographic characteristics of the respondents influenced knowledge and practice relating to unregistered medications. KEY FINDINGS: A total of 649 respondents completed the questionnaire with the majority being female (66.1%), unmarried (66.5%), Malay (52.5%) and possessing a bachelor's degree (53.5%). The knowledge of the public surveyed regarding unregistered (unlicensed) medications was lacking, especially in being able to identify a registered health product in Malaysia and formally complaining if necessary. The respondents agreed that currently, there are insufficient laws and educational programmes to tackle the issue. The respondents exhibited good practice habits by purchasing their medications from healthcare professionals. Mean knowledge score was positively correlated to practice scores at rs  = 0.423 (P-value < 0.001). Ethnicity and education level were significant predictors of knowledge scores, while ethnicity, age and income group influenced practice-related items. CONCLUSION: While respondents generally had good medication purchasing practices, their knowledge about and attitude to unregistered medications indicated the need for more educational awareness of the issues.

Multiplicative modelling of EQ-5D-3L TTO and VAS values.

OBJECTIVE: This study aimed to test multiplicative modelling with EQ-5D-3L time-trade-off (TTO) and visual analogue scale (VAS) values. METHODS: A multi-stage sampling design was adopted for the study and data collection took place in three phases in 2010, 2011, and 2012 in the Northern region of Malaysia. Face-to-face interviews involved respondents answering both 13 TTO and 15 VAS valuation tasks were carried out. Both additive and multiplicative model specifications were explored using the valuation data. Model performance was evaluated using out-of-sample predictive accuracy by applying the cross-validation technique. The distribution of the model values was also graphically compared on Bland-Altman plots and kernel density distribution curves. RESULTS: Data from 630 and 611 respondents were included for analyses using TTO and VAS models, respectively. In terms of main-effects specifications, cross-validation results revealed a slight superiority of multiplicative models over its additive counterpart in modelling TTO values. However, both main-effects models had roughly equal predictive accuracy for VAS models. The non-linear multiplicative model with I32 term, MULT7_TTO, performed best for TTO models; while, the linear additive model with N3 term, ADD11_VAS, outperformed the other VAS models. Multiplicative modelling neither altered the dimensional rankings of importance nor did it change the distribution of values of the health states. CONCLUSION: Using EQ-5D-3L valuation data, multiplicative modelling was shown to improve out-of-sample predictive accuracy of TTO models but not of VAS models.

Psychometric performance assessment of Malay and Malaysian English version of EQ-5D-5L in the Malaysian population.

PURPOSE: To determine the psychometric properties and performance of Malay and English versions of the EQ-5D-5L descriptive instrument in the general Malaysian population. METHODS: 1137 members of the Malaysian general public were sampled in this national study. Respondents were recruited by quota sampling of urbanicity, gender, age, and ethnicity. In face-to-face interviews, respondents first answered the EQ-5D-5L questionnaire administered using the EQ-Valuation Technology software, and then completed the EQ-5D-3L questionnaire on paper. A subgroup of the respondents were given paper form of EQ-5D-5L for completion within 2 weeks for test-retest reliability. Ceiling effects, response redistribution, informativity, and convergent validity were compared between EQ-5D-5L and ED-5D-3L separately by Malay and English language versions. RESULTS: The proportion of 'full health' responses (11111) drastically decreased by 25.55% and 15.74% in the Malay and English language versions indicating lower ceiling effects in EQ-5D-5L. Inconsistencies from response redistribution was below 6% for all dimensions across languages. The measure of relative informativity was comparatively higher in EQ-5D-5L than in EQ-5D-3L in both language versions, with the exception of dimensions mobility and pain/discomfort in the English version. Convergent validity in terms of correlation with EQ-VAS was relatively better for EQ-5D-5L dimensions, with pain/discomfort of the Malay version having the strongest correlation (|r| = 0.37). Also, reliability testing revealed moderate to poor agreements on all 5L dimensions. CONCLUSIONS: EQ-5D-5L fared better in terms of psychometric performance compared to EQ-5D-3L for both language versions. This encourages the application of the EQ-5D-5L in health-related research in Malaysia.

EQ-5D-5L Valuation for the Malaysian Population.

OBJECTIVES: The aim of this study was to develop an EQ-5D-5L value set reflecting the health preferences of the Malaysian adult population. METHODS: Respondents were sampled with quotas for urbanicity, gender, age, and ethnicity to ensure representativeness of the Malaysian population. The study was conducted using a standardized protocol involving the EuroQol Valuation Technology (EQ-VT) computer-assisted interview system. Respondents were administered ten composite time trade-off (C-TTO) tasks and seven discrete choice experiment (DCE) tasks. Both linear main effects and constrained non-linear regression models of C-TTO-only data and hybrid models combining C-TTO and DCE data were explored to determine an efficient and informative model for value set prediction. RESULTS: Data from 1125 respondents representative of the Malaysian population were included in the analysis. Logical consistency was present in all models tested. Using cross-validation, eight-parameter models for C-TTO only and C-TTO + DCE hybrid data displayed greater out-of-sample predictive accuracy than their 20-parameter, main-effect counterparts. The hybrid eight-parameter model was chosen to represent the Malaysian value set, as it displayed greater out-of-sample predictive accuracy over C-TTO data than the C-TTO-only model, and produced more precise estimates. The estimated value set ranged from - 0.442 to 1. CONCLUSIONS: The constrained eight-parameter hybrid model demonstrated the best potential in representing the Malaysian value set. The presence of the Malaysian EQ-5D-5L value set will facilitate its application in research and health technology assessment activities.