Valuing preferences for EQ-5D health states in the Thai general population

Health care expenditures have been increasing rapidly. Economic evaluation can be used to aid decision making on resource allocations to secure a more efficient use of scarce resources. In cost-utility analysis, one method used to measure health outcomes is the Quality adjusted life year (QALY). Given the wide differences in clinical settings, health systems and religious beliefs, "utility" scores should be derived from the local population. This thesis aims to estimate population-based preference scores for health from the Thai general population. The generic health description EQ-SO is used as a proxy to describe health. This measure was selected because it has been translated officially into Thai and the measure seems to be straightforward to use. A representative sample was randomly recruited using a stratified four-stage sampling method. A series of pilot studies were conducted to develop the interview protocol based on the Measurement and Valuation in Health (MVH) protocol. A group of interviewers were employed and extensively trained to interview the respondents. A sample of 1,409 Thai respondents was interviewed during May - August 2007 in 17 provinces in face-to-face interviews. Eighty-six health states, classified into twelve sets, were used in the interview. logical inconsistency was identified when a higher score was given to a poorer state. The greatest number of inconsistent responses was identified in the scores derived using the Time trade-off (TTO) interview. A Negative binomial regression model was used to analyse the determinants of the numbers of inconsistencies. Elderly respondents and those with a lower education level tend to make more inconsistent responses. A Random effects model was used to estimate the model to predict the preference scores. The best model was chosen on the basis of logical inconsistency in the predicted scores, model robustness, parsimony and the responsiveness of the predicted scores. The best model is the model using the variables from Dolan 1997 model estimated from the scores given by the respondents with fewer than 11 inconsistencies. The model still suffers from heteroskedasticity, and floor and ceiling effects were identified. The Thai scores and the scores derived from respondents in the other five countries were extensively compared to examine the extent of the differences. It seems that the Thai scores are more similar to those of the UK. A cost utility analysis of the prevention and control measures for cervical cancer in Thailand was used to demonstrate the difference of cost per QALYs if the scores from other countries were used to approximate the Thai preferences. The thesis makes a number of contributions. The modelled scores are the first original population-based preference scores on health derived from the Thai general population. The determinants of logical inconsistency were examined, as well as an exploratory qualitative interview to learn the strategies that respondents employed to cope with the preference interview. Three reasons are identified to explain the high level of inconsistent responses. Respondents may: (1) have difficulties imagining themselves living in the hypothetical states; (2) use only part of the given information in the health cards or add other information to assist their decisions; and (3) have difficulties in trying to understand the elicitation methods, especially the no. Including the inconsistent responses had, to some extent, significant impacts on the model specifications and the modelled scores. Exclusion of the scores from the highly inconsistent respondents was justified because the scores may not represent their preferences towards health. The results from this thesis should be taken into account for future surveys to be successfully administered. Close collaborations with the field coordinators and arrangement of appropriate interview settings contribute greatly to the success of the survey

Valuing preferences for EQ-5D health states in the Thai general population

Health care expenditures have been increasing rapidly. Economic evaluation can be used to aid decision making on resource allocations to secure a more efficient use of scarce resources. In cost-utility analysis, one method used to measure health outcomes is the Quality adjusted life year (QALY). Given the wide differences in clinical settings, health systems and religious beliefs, "utility" scores should be derived from the local population. This thesis aims to estimate population-based preference scores for health from the Thai general population. The generic health description EQ-SO is used as a proxy to describe health. This measure was selected because it has been translated officially into Thai and the measure seems to be straightforward to use. A representative sample was randomly recruited using a stratified four-stage sampling method. A series of pilot studies were conducted to develop the interview protocol based on the Measurement and Valuation in Health (MVH) protocol. A group of interviewers were employed and extensively trained to interview the respondents. A sample of 1,409 Thai respondents was interviewed during May - August 2007 in 17 provinces in face-to-face interviews. Eighty-six health states, classified into twelve sets, were used in the interview. logical inconsistency was identified when a higher score was given to a poorer state. The greatest number of inconsistent responses was identified in the scores derived using the Time trade-off (nO) interview. A Negative binomial regression model was used to analyse the determinants of the numbers of inconsistencies. Elderly respondents and those with a lower education level tend to make more inconsistent responses. A Random effects model was used to estimate the model to predict the preference scores. The best model was chosen on the basis of logical inconsistency in the predicted scores, model robustness, parsimony and the responsiveness of the predicted scores. The best model is the model using the variables from Dolan 1997 model estimated from the scores given by the respondents with fewer than 11 inconsistencies. The model still suffers from heteroskedasticity, and floor and ceiling effects were identified. The Thai scores and the scores derived from respondents in the other five countries were extensively compared to examine the extent of the differences. It seems that the Thai scores are more similar to those of the UK. A costutility analysis of the prevention and control measures for cervical cancer in Thailand was used to demonstrate the difference of cost per QALYs if the scores from other countries were used to approximate the Thai preferences. The thesis makes a number of contributions. The modelled scores are the first original population-based preference scores on health derived from the Thai general population. The determinants of logical inconsistency were examined, as well as an exploratory qualitative interview to learn the strategies that respondents employed to cope with the preference interview. Three reasons are identified to explain the high level of inconsistent responses. Respondents may: (1) have difficulties imagining themselves living in the hypothetical states; (2) use only part of the given information in the health cards or add other information to assist their decisions; and (3) have difficulties in trying to understand the elicitation methods, especially the no. Including the inconsistent responses had, to some extent, significant impacts on the model specifications and the modelled scores. Exclusion of the scores from the highly inconsistent respondents was justified because the scores may not represent their preferences towards health. The results from this thesis should be taken into account for future surveys to be successfully administered. Close collaborations with the field coordinators and arrangement of appropriate interview settings contribute greatly to the success of the survey

Variation of health-related quality of life assessed by caregivers and patients affected by severe childhood infections.

BACKGROUND: The agreement between self-reported and proxy measures of health status in ill children is not well established. This study aimed to quantify the variation in health-related quality of life (HRQOL) derived from young patients and their carers using different instruments. METHODS: A hospital-based cross-sectional survey was conducted between August 2010 and March 2011. Children with meningitis, bacteremia, pneumonia, acute otitis media, hearing loss, chronic lung disease, epilepsy, mild mental retardation, severe mental retardation, and mental retardation combined with epilepsy, aged between five to 14 years in seven tertiary hospitals were selected for participation in this study. The Health Utilities Index Mark 2 (HUI2), and Mark 3 (HUI3), and the EuroQoL Descriptive System (EQ-5D) and Visual Analogue Scale (EQ-VAS) were applied to both paediatric patients (self-assessment) and caregivers (proxy-assessment). RESULTS: The EQ-5D scores were lowest for acute conditions such as meningitis, bacteremia, and pneumonia, whereas the HUI3 scores were lowest for most chronic conditions such as hearing loss and severe mental retardation. Comparing patient and proxy scores (n = 74), the EQ-5D exhibited high correlation (r = 0.77) while in the HUI2 and HUI3 patient and caregiver scores were moderately correlated (r = 0.58 and 0.67 respectively). The mean difference between self and proxy-assessment using the HUI2, HUI3, EQ-5D and EQ-VAS scores were 0.03, 0.05, -0.03 and -0.02, respectively. In hearing-impaired and chronic lung patients the self-rated HRQOL differed significantly from their caregivers. CONCLUSIONS: The use of caregivers as proxies for measuring HRQOL in young patients affected by pneumococcal infection and its sequelae should be employed with caution. Given the high correlation between instruments, each of the HRQOL instruments appears acceptable apart from the EQ-VAS which exhibited low correlation with the others

Health Related Quality of Life among Patients with Tuberculosis and HIV in Thailand

INTRODUCTION: Health utilities of tuberculosis (TB) patients may be diminished by side effects from medication, prolonged treatment duration, physical effects of the disease itself, and social stigma attached to the disease. METHODS: We collected health utility data from Thai patients who were on TB treatment or had been successfully treated for TB for the purpose of economic modeling. Structured questionnaire and EuroQol (EQ-5D) and EuroQol visual analog scale (EQ-VAS) instruments were used as data collection tools. We compared utility of patients with two co-morbidities calculated using multiplicative model (U(CAL)) with the direct measures and fitted Tobit regression models to examine factors predictive of health utility and to assess difference in health utilities of patients in various medical conditions. RESULTS: Of 222 patients analyzed, 138 (62%) were male; median age at enrollment was 40 years (interquartile range [IQR], 35-47). Median monthly household income was 6,000 Baht (187 US$; IQR, 4,000-15,000 Baht [125-469 US$]). Concordance correlation coefficient between utilities measured using EQ-5D and EQ-VAS (U(EQ-5D) and U(VAS), respectively) was 0.6. U(CAL) for HIV-infected TB patients was statistically different from the measured U(EQ-5D) (p-value<0.01) and U(VAS) (p-value<0.01). In tobit regression analysis, factors independently predictive of U(EQ-5D) included age and monthly household income. Patients aged ≥40 years old rated U(EQ-5D) significantly lower than younger persons. Higher U(EQ-5D) was significantly associated with higher monthly household income in a dose response fashion. The median U(EQ-5D) was highest among patients who had been successfully treated for TB and lowest among multi-drug resistant TB (MDR-TB) patients who were on treatment. CONCLUSIONS: U(CAL) of patients with two co-morbidities overestimated the measured utilities, warranting further research of how best to estimate utilities of patients with such conditions. TB and MDR-TB treatments impacted on patients' self perceived health status. This effect diminished after successful treatment

An overview of the utilisation of microalgae biomass derived from nutrient recycling of wet market wastewater and slaughterhouse wastewater

Microalgae have high nutritional values for aquatic organisms compared to fish meal, because microalgae cells are rich in proteins, lipids, and carbohydrates. However, the high cost for the commercial production of microalgae biomass using fresh water or artificial media limits its use as fish feed. Few studies have investigated the potential of wet market wastewater and slaughterhouse wastewater for the production of microalgae biomass. Hence, this study aims to highlight the potential of these types of wastewater as an alternative superior medium for microalgae biomass as they contain high levels of nutrients required for microalgae growth. This paper focuses on the benefits of microalgae biomass produced during the phycore-mediation of wet market wastewater and slaughterhouse wastewater as fish feed. The extraction techniques for lipids and proteins as well as the studies conducted on the use of microalgae biomass as fish feed were reviewed. The results showed that microalgae biomass can be used as fish feed due to feed utilisation efficiency, physiological activity, increased resistance for several diseases, improved stress response, and improved protein retention

Genetic Parameters for Production Traits of Rhode Island Red and White Plymouth Rock Breeds Selected under Tropical Condition in Thailand

Egg production data on Rhode Island Red and White Plymouth Rock hens selected for 11 generations under a tropical environment in Thailand were used to estimate genetic parameters for age at first eggs (AFE), body weight at first eggs (BFE), weight of first eggs (WFE), egg production from 1st day to 17 weeks of lay (EGG) and average egg weight at 17th week of lay (EWT). Estimated heritability for AFE, BFE, WFE, EGG and EWT of RIR hens were 0.46, 0.51, 0.28, 0.33 and 0.47 and for WPR hens these were 0.44, 0.41, 0.33, 0.30 and 0.43, respectively. AFE is positively correlated with BFE, WFE and EWT and negatively correlated with EGG in both breeds. EGG was negatively correlated with both WFE and EWT in both breeds. The estimated genetic parameters will be used in selection strategies to improve the productivity of both breeds

Genetic Associations Between Early and Late Growth with Sexual Maturity in Thai Native Chickens

The associations between early and late growth rates with sexual maturity of Lueng Hang Kao Kabinburi (LHKK) native chicken in Thailand were explored. Five generations of data from 2003 to 2007, involving 11,588 chickens, were collected at Kabinburi Livestock Research and Breeding Centre (KLRBC). Body weight measured from day-old (BW1D) to 24 weeks of age at 4 weekly intervals of 4 (BW4), 8 (BW8), 12 (BW12), 16 (BW16), 20 (BW20), 24 (BW24) weeks, and sexual maturity traits, age at first egg (AFE) and egg weight at first egg (EWFE), were recorded. The growth rates were grouped into 5 categories: BW1D to BW8 (Growth_1), BW4 to BW12 (Growth_2), BW8 to BW16 (Growth_3), BW12 to BW20 (Growth_4), and BW16 to BW24 (Growth_5). Growth_1 to 3 represented early growth and Growth_4 and 5 represented late growth. Genetic correlations were estimated between early and late growth rates against AFE and EWFE using Restricted Maximum Likelihood. Growth_1 had a favourable genetic correlation of -0.15 with AFE and a high positive (favourable) genetic correlation of 0.42 with EWFE. Growth rate between Growth_4 and Growth_5 had unfavourable genetic correlations of 0.08 and 0.30, respectively, with AFE, and favourable genetic correlations of 0.28 and 0.31, respectively, with EWFE. This study indicated that selecting for higher growth rate between day-old to 8 weeks of age would also improve sexual maturity by reducing the AFE and increasing the EWFE of LHKK chicken in Thailand

Using random regression models to estimate genetic variation in growth pattern and its association with sexual maturity of Thai native chickens

Genetic (co)variances and parameters between body weights (BW) across the growth trajectory were estimated using a univariate random regression (RR) animal model. The effect of growth rates (GH) on age at first egg (AFE) and egg weight at first egg (EWFE) were explored using a series of univariate and bivariate analyses.Body weights were taken from Thai native chickens at hatch day to 168 days of age. The model included interactions between age with hatch nested within year and sex as fixed effects, and random effects of direct additive genetic, direct permanent environmental, maternal genetic and maternal permanent environmental effects. All random effects were fitted as regressions to animals’ age via quadratic Legendre polynomials and fitting six classes of residual variances was identified as an optimal variance structure to estimate parameters.Genetic and phenotypic variances for BW increased with increasing age. Estimated heritabilities for direct additive (h2 a) and maternal genetic (h2 m) effects on BW traits ranged from 0.34 to 0.54, and 0.04 to 0.06, respectively. Estimated variance ratios for direct (c2 ape) and maternal permanent environmental (c2 mpe) effects ranged from 0.19 to 0.48 and 0.10 to 0.12, respectively. Estimated correlations between weights at different ages were high for all random effects.Estimated h2 a for six GH traits ranged from 0.06 to 0.28, while for AFE and EWFE these were 0.24 and 0.16, respectively. Estimated h2 m and c2 mpe were low for GH. Estimated genetic correlations between GH and AFE ranged from −0.22 to 0.02 and, between GH and EWFE, ranged from −0.05 to 0.40. These estimates suggested that selecting high GH chickens at 28 days of age can be expected to reduce AFE and to increase EWFE