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Dr. Munir A Khan Research Fellow, Centre for Health Economics Monash University 23 June 2010

CHE Seminar Series 2010 A Comparison of Multi Attribute Utility (MAU) Instruments with Instruments for Measuring Subjective Wellbeing. Dr. Munir A Khan Research Fellow, Centre for Health Economics Monash University 23 June 2010. Contents . Introduction and Literature Background

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Dr. Munir A Khan Research Fellow, Centre for Health Economics Monash University 23 June 2010

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  1. CHE Seminar Series 2010 A Comparison of Multi Attribute Utility (MAU) Instruments with Instruments for Measuring Subjective Wellbeing Dr. Munir A KhanResearch Fellow, Centre for Health Economics Monash University 23 June 2010

  2. Contents • Introduction and Literature • Background • Aims and Objectives • Data and Sample size • Bangladeshi migrants • Australian public • MAU and SWB Instruments • Methods • Results • Discussion • Conclusion

  3. Introduction and Literature Backgrounds HR-QoL is now recognised to be a major finishing point in the evaluation of health care programs. To date a handful of generic instruments have been developed and used to measure HR-QoL of general public and patients. There are over 800 instruments which purport to measure QoL in some form. These include psychometric, disease-specific and generic MAU and SWB instruments. Instruments describe health states with greater or lesser accuracy. In general the fewer the number of items and dimensions the less sensitive it will be to differences in health states. Significant differences found between instruments. In general the HUI3 and EQ-5D generate higher utility scores for both public and patients A large number of comparative studies have been published using MAU instruments to measure and examine HR-QoL (Khan and McKie 2010).

  4. Introduction and Literature 2 approaches to assess HR-QoL: 1)non-preference-based; 2) preference based. The non-preference based approach consists of describing various aspects of HR-QoL and ask questions about the presence, severity and frequency of symptoms or the ability to perform daily tasks (example: SF-36) The preference based approach consists of asking the respondents to make a judgement about the value of life within a given health state (example: AQoL). It measures the strength of preference for health conditions. The preference-based assessment can be obtained by using the Rating Scale (RS), the Time trade-off (TTO), or Standard Gamble (SG) techniques. The MAU instruments may be used with or without the use of utility weights. SWB is measured on the basis of participants self-reported appraisal of and satisfaction with their current level of functioning compared to what they perceive to be possible or ideal. None of these instruments have been used for measuring the QoL of a small ethnic community like Bangladesh-born migrants in Australia.

  5. Introduction and Literature Data and Sample Size Total sample size for this study is 506. This sample includes both Australian public and Bangladeshi migrants. Bangladeshi migrants: N = 158 Australian public: N = 348

  6. Aims and objectives The overall aim of this paper is to compare the above four MAU two SWB (Personal Wellbeing Index (PWI) and Satisfaction of With Life Scale (SWLS)) instruments in measuring HR-QoL of general public. The specific aims of this paper are threefold: i) to present a comparison of four MAU and two SWB instruments to assess the effectiveness of each in measuring QoL of general public; ii) to compare the QoL and lifestyle of the Bangladeshi community with the Australian population; and iii) to validate four MAU instruments with two SWB instruments.

  7. MAU and SWB Instruments What is MAU Instruments? • It is a preference based instrument. It is called the multi-attribute instrument because it describes different aspects of health. Score can be both psychometric non-weighted or preference based weighted utility. • Instruments purport to measure the same thing, they may not be interchangeable. To date no multi-instrument comparison has been done for any small ethnic community. MAU Instruments Used: AQoL-8D, EQ-5D, SF-6D, and HUI3. These instruments measure health-related utility on a scale of ‘0 to 1’ where 0 represents death and 1 represents full health. SWB Instruments Used : SWLS and PWI 4 MAU and 2 SWB instruments have been selected because of their global use and suitability.

  8. MAU and SWB Instruments • Characteristics of MAU and SWB Instruments • The four MAU and two SWB quality of life instruments used in this paper were selected because of their widespread use and or a prior suitability. The characteristics of these instruments, including the number of dimensions, items and response levels are provided in Table 1. Table 1: Characteristics of six instruments

  9. Background and Literature: Description of 7 MA Instruments 4 MAU and 2 SWB Instruments Description of 6 Instruments • The AQoL-8D instrument has been recently developed in the Centre for Health Economics (CHE), Monash University. The instrument consists of the eight dimensions and 35 items. The number of items and the number of responses per item vary. • The EQ-5D (EuroQoL-5D) is a standardised instrument which was developed by a multi-disciplinary group of researchers from seven centre across five countries for use as a measure of health outcome. • The SF-6D was derived from the SF-12 and SF-36. The SF-36 has become the most widely used measure of general health in clinical studies throughout the world. • The Health Utilities Index Mark 3 (HUI3) is a prominent measure of HR-QoL and widely used in population health surveys especially in Canada, clinical studies and cost-utility analyses. .

  10. Background and Literature: Description of 7 MA Instruments 4 MAU and 2 SWB Instruments • The Personal Wellbeing Index (PWI) was developed from the Comprehensive Quality of Life Scale (ComQol) to measure the subjective dimension of QoL – Subjective Wellbeing. • The PWI scale contains eight items of satisfaction, each one corresponding to a quality of life domain as: standard of living, health, achieving in life, relationships, safety, community-connectedness, future security, and spirituality/religion. • These eight domains are theoretically embedded with general question to people to rate their global life satisfaction: ‘How satisfied are you with your life as a whole’. (used ten-point likert scale: completely dissatisfied to completely satisfied). • Satisfaction with Life Scale (SWLS) is connected with five statements with which seven level of agreement or disagreement is attached. • Each statement is associated with the level of satisfaction to the quality of life as: most ways life is close to ideal; the conditions of life are excellent; satisfied with life, so far gotten the things wanted in life; and if I could live my life over, I would change almost nothing. (used seven-point likert scale: strongly disagree to strongly agree). .

  11. Background and Literature: Characteristics of 7 MA Instruments 4 MAU and 2 SWB Instruments • Weighted utility scores were obtained from EQ-5D scoring index (Johnson 2004), SF-6D (Brazier, 2003). HUI3 (Health Utilities Inc, 2008), and AQoL-8D (AQoL 2010) algorithms. • For 2 SWB instruments, unweighted scores were obtained from the item responses from the participants using the following formula: • Where x = Individual’s total score from summing the response category rank; xmin = Instrument’s total minimum score; xmax = Instrument’s total maximum score. This simple algorithm results in values which vary between 0.0 to 1.0

  12. Methods • This is an empirical study where data is mainly collected from primary sources. • The questionnaire was prepared to collect general public’s self-reported health status and other social, demographic and lifestyle data. All six MAU and SWB instruments were included for Bangladeshi migrants in the questionnaire. • Upon agreement people were given soft copy and a hard copy of the questionnaire. A questionnaire survey was also conducted face to face among the Bangladesh-born migrants at different locations. • For general public data were collected through online (Lime survey). AQoL-8D and PWI instruments were included the survey.

  13. Results Total sample size used for this study is 506 including general Australian public (348). Among the Bangladeshi participant s, 54% were male; 78% married; 85% living with their family; 91% had graduate or postgraduate qualifications and about 73% were employed either full-time or part-time. Over 50% of the participants possess excellent or very good health and 83% do not have any significant illness. Both males and females were found to be more overweight but less obese compared with the Australian population. About 80% reported that they never drank alcohol or smoked cigarettes. Length of stay in the host country was found to be important for the adaptation process. About 54% of the respondents had lived less than 10 years in Australia. All four MAU and two SWB instruments were highly correlated. (Table 2) The recently developed AQoL-8D was most strongly correlated with EQ-5D, SF-6D and HUI3. In general the mean utility score for MAU instruments is higher (=> .86) than two SWB instruments (=<.75). AQoL-8D produced the highest proportion (85%) of ‘excellent’ QoL scores for people, followed by the EQ-5D (82%), HUI3 (80%), SF-6D (73%), PWI (38%) and SWLS (31%) (Table 3).The EQ-5D and HUI3 produced the highest number of individuals in full health (n = 91) and PWI the fewest (n = 13) (Fig 1). The logistic analysis shows the importance of employment to the quality of life, but also indicates that age plays a role (Table 3a).

  14. Results • The analysis of multiple regressions shows that all four MAU instruments contributed in explaining the SWB instruments, AQoL-8D and HUI3 instruments were found to be strongest unique contributors in explaining two SWB instruments: average PWI and SWLS (Table 4). When whole life regressed on 4 MAU instruments, similar result was found (R2 = .334; p = <.01). • The frequency distribution of full health of six instrument shows that when SF-6D records excellent health the other three MAU instruments also record excellent health. However, in contrast, when EQ-5D or HUI3 record full health, the AQoL-8D and the SF-6D record fewer individuals in full health: only 90 and 87 respondents for AQoL-8D and 82 and 87 respondents for the SF-6D. When two SWB instruments records full health, all four MAU instruments also records full health (except EQ-5D and HUI3 in the case of SWLS). One respondent has shifted from the range 0.81–1.00 to the range of 0.61-0.80 (Table 5).

  15. Results

  16. Results Comparison of six instrument and level of HR-QoL

  17. Results Comparison of 4 MAU and 2 SWB instruments

  18. Results Table 3a: Socio-economic and lifestyle factors and Quality of Life

  19. Results Validation of four MAU instruments with two SWB instruments

  20. Results When Whole Life Regress on 4 MAU instruments

  21. Table 5: Comparison of six instruments: when particular instrument records full health - Frequency distribution Results

  22. Discussion The results indicate that the vast majority of Bangladeshi migrants are healthy and have no significant illness over and above the Australian population. The self-reported health conditions reinforce this conclusion. Lifestyle characteristics of the migrants indicate that this community is different from the Australian general population. More than three quarters do not smoke or drink alcohol and more than 90% eat home-cooked traditional Bangladeshi meals. All these lifestyle aspects are associated with HR-QoL. The analysis of length of stay on BMI indicates a significant effect and is consistent with previous results. The sensitivity of instruments varied greatly well over half the respondents registering no problem with any element of their QoL on the EQ5D and HUI scales. The wide variation in instrument scores is probably due to the varied number of dimensions, items and response levels. The instruments with the fewest response levels tended to produce higher average instrument scores even after standardisation. AQoL-8D uses 35 items within eight dimensions, making it a more sensitive instrument for capturing different aspects of HR-QoL. The results indicated the instrument produced varied proportions of migrants falling within the excellent health range: 85% by the AQoL-8D to 31% by the SWLS. The factor analysis of 2 SWB instruments shows all the questions were strongly correlated and loaded highly on two distinct components: PWI and SWLS. These two instruments were not related to each other. The result of multiple regressions suggests that all four MAU instruments has strongest unique contribution to explaining these two scales.

  23. Conclusion This research addresses the three specific aims and provides a comparison of the effectiveness of four MAU and two SWB instruments for measuring quality of life. It uses both weighted utility and non-weighted psychometric scores and relatively simple sensitivity test. Despite these weaknesses, this study provides both a model and baseline information for the assessment and validation of MAU and SWB instruments comparison for a small ethnic community and general public.

  24. - The End – Any questions, comments or feedback?

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