Mahderekal PPT presentation on multiatribute.pptx

pharmacoeconomics

1. Presentation on : Multi-attribute utility measurement tools in quality of life studies Generic tools and Disease specific tools Presenter: Mahderekal welegewergis ID NO : CHS/PRB/001/16

2. Presentation Objectives At the end of the presentation, audience is expected to describe: Multi-attribute utility theory The two types of Multi-attribute utility measurement tools in quality of life studies Generic tools Disease specific tools 2

3. Introduction Measuring preferences for health outcomes is crucial in healthcare decision-making but can be complex and time-consuming . An efficient alternative is the utilization of pre-scored multi-attribute health status classification systems . The areas of main focus are the four prominent generic tools: Quality of Well-Being (QWB), Health Utilities Index (HUI), EQ-5D , and Short Form 6D (SF-6D ). Additionally , we'll also touch the disease specific systems: S uch as EORTC QLQ-C30, CAT, AQLQ, and others 3

4. Multi-attribute utility theory Traditional von Neumann-Morgenstern utility theory was extended by Keeney and Raiffa in 1976 to cover multi-attribute outcomes. An additional assumption was added to the three axioms of utility theory (completeness, transitivity, and continuity) to accommodate this extension. The assumption is that utility independence among attributes can be represented by at least first-order utility independence, and possibly by stronger forms such as mutual utility independence and additive independence. 4

5. First-order utility independence : Implies no interaction between preferences among levels on any one attribute and fixed levels for other attributes. Example : Level 3 mobility has a utility of 0.6 on the mobility subscale regardless of health status levels on other attributes. The relative scaling within the mobility subscale must remain constant. 5

6. Mutual utility independence A stronger assumption where there's no interaction between preferences for levels on some attributes and fixed levels for other attributes. This characteristic must hold for all possible subsets of attributes. - Example: Level 2 on sensation coupled with level 3 on mobility has a utility of 0.7 on the sensation-mobility subscale regardless of health status levels on other attributes. The relative scaling within the sensation-mobility subscale must remain constant. 6

7. Additive utility independence Implies no interaction for preferences among attributes at all . - Example: A change from level 1 to level 3 mobility would reduce overall utility by 0.2 regardless of levels on other attributes. 7

8. Implications of the three independence assumptions - Lead to three different multi-attribute functions: The simplest assumption, first-order utility independence, leads to the most complex mathematical function ( multilinear function). Mutual utility independence leads to the multiplicative function. Additive independence, the strongest assumption, leads to the simplest function (additive function). 8

9. Generic Tools Generic tools are designed to assess QoL across different health conditions and populations, offering a standardized approach for comparison. - Examples include the QWB,EQ-5D , SF-6D, and Health Utilities Index (HUI ). These tools typically comprise multiple dimensions allowing respondents to rate their health status within each dimension. 9

10. Quality of Well-Being (QWB ) The Quality of Well-Being (QWB) scale, developed by Kaplan and Anderson in 1988 and later revised in 1996, I s a tool used to classify patients based on four attributes: mobility, physical activity, social activity, and symptom-problem complex . This scale aims to assess the subjective well-being of patients by considering their functional abilities, social interactions, and symptoms . 10

11. Methodology The QWB scale assesses patients based on their perceived quality of life on a single day, with respondents asked to rate various states using a scale anchored by death and perfect health. If a patient experiences multiple symptoms or problems, the most undesirable one, as perceived by the patient, is utilized for classification. The original QWB questionnaire necessitated a trained interviewer and was time-consuming, taking approximately 15 minutes for classification. Subsequently , a self-administered version, the QWB-SA, was developed, it also took an average of 14 minutes for patients to complete. 11

12. QWB System and Scoring Function Each attribute is assessed using a scoring function ranging from 0.0 to 1.0, with higher scores indicating better functioning and well-being . The scoring function is derived from empirical data obtained from a representative sample of the general population, ensuring its applicability and reliability. 12

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16. EQ-5D ( EuroQol Group 5-Dimension) The EuroQoL Group, a consortium of investigators in Western Europe, developed the EQ-5D as a standardized instrument for measuring health-related quality of life ( HRQoL ). Initially, the system consisted of six attributes: mobility, self-care, main activity, social relationships, pain, and mood. However , it was later revised to include five attributes: mobility, self-care, usual activity, pain/discomfort, and anxiety/depression . Each attribute has three levels: no problem, some problems, and major problems, resulting in 243 possible health states. Two additional states, 'unconscious' and 'dead', bring the total to 245 health states. 16

17. Preference Scoring and Measurement Preferences for EQ-5D were measured using the Time Trade-Off (TTO) technique on a random sample of approximately 3000 members of the adult population in the UK in 1995/1996. The scoring function was developed using econometric modeling, ranging from 0.0 (indicating dead) to 1.0 (representing perfect health). 17

18. EQ-5D classification system ??? 18

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20. Short Form 6D (SF-6D ) The SF-6D is a utility instrument derived from the Short Form 36 (SF-36), a widely used health-related quality of life questionnaire. The SF-6D was developed to convert SF-36 study results into utilities, facilitating the calculation of Quality-Adjusted Life Years (QALYs ). The SF-6D consists of a multi-attribute health status classification system with six attributes(Physical functioning, role limitations, social functioning, pain, mental health, and vitality) The system includes four to six levels on each attribute, resulting in 18,000 unique health states 20

21. Utility scoring Function The scoring model for SF-6D was developed based on standard gamble utility measurements on a random sample (n = 836) of the UK general population. Each subject provided utilities for six states, resulting in a total of 249 different health states valued. The scoring table is then utilized to compute the utilities, ranging from 0.0 (dead) to 1.0 (healthy). 21

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24. Health Utilities Index (HUI ) The Health Utilities Index (HUI) comprises two systems: HUI2 and HUI3. Each system includes a health status classification system and a utility scoring formula. The scoring formulas for both HUI2 and HUI3 are based on standard gamble utilities measured on the general public 24

25. Selection Between HUI2 and HUI3 For most applications, HUI3 is recommended as the primary analysis tool due to its more detailed descriptive system, full structural independence, and availability of population norms. HUI2 can be used in a secondary role to provide additional insights, particularly because it includes attributes such as self-care, emotion (with a focus on worry/anxiety), and fertility. HUI2 can also serve as a sensitivity analysis tool . 25

26. Cont ’ While the HUI3 classification system closely resembles that of HUI2, HUI3 dropped the application-specific attribute fertility and expanded the sensory attribute into three distinct attributes: vision, hearing, and speech. Other changes were made to enhance structural independence ( orthogonality ) among attributes, achieving it in the HUI3 system. 26

27. Scoring Functions Both HUI2 and HUI3 employ multiplicative multiattribute utility functions. Both systems have states worse than death scored as equal to death . B ased on standard gamble utilities measured on the general public, the scores range from 0 (dead) to 1 (perfect health) on the conventional scale. 27

28. Health Utilities Index mark 2 classification system 28

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30. Health Utilities Index mark 3 classification system 30

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32. Disease-Specific Tools While generic tools offer broad applicability, disease-specific tools focus on the unique aspects of particular health conditions and their impact on QoL . These tools capture disease-specific symptoms, functional limitations, and emotional well-being, providing insights that may be missed by generic measures alone. 32

33. Disease-Specific Tools Disease-specific tools include: The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) for cancer, The COPD Assessment Test (CAT) for chronic obstructive pulmonary disease (COPD ), and the Asthma Quality of Life Questionnaire (AQLQ) for asthma and others… 33

34. EORTC QLQ-C30 The EORTC QLQ-C30 is a disease-specific instrument developed for cancer patients to evaluate various aspects of health-related quality of life . It includes scales for physical functioning, emotional functioning, social functioning, fatigue, pain, and global health status, as well as symptoms scales for common cancer-related symptoms such as nausea, vomiting, and dyspnea . The questionnaire provides a comprehensive assessment of cancer patients' quality of life and allows for the monitoring of treatment outcomes and symptom management in clinical trials and oncology research. 34

35. COPD Assessment Test (CAT ) The COPD Assessment Test (CAT) is specifically tailored to assess the impact of chronic obstructive pulmonary disease (COPD) on patients' QoL. It evaluates symptoms such as cough, sputum production, breathlessness, and the impact of COPD on daily activities and emotional well-being. CAT scores assist healthcare professionals in monitoring disease progression, optimizing treatment strategies, and improving patient outcomes . 35

36. Minnesota Living with Heart Failure Questionnaire (M LHFQ) Specifically designed for patients with heart failure, the Minnesota Living with Heart Failure Questionnaire assesses the impact of heart failure on different domains of life, including physical symptoms, emotional well-being, social activities, and overall quality of life . It measures the degree of impairment or limitation experienced by individuals due to heart failure symptoms, providing insights into the psychosocial and functional consequences of the condition. 36

37. Asthma Quality of Life Questionnaire (AQLQ) The Asthma Quality of Life Questionnaire (AQLQ) is designed to evaluate the impact of asthma on patients' daily functioning and emotional well-being . It covers domains such as symptoms, activity limitation, emotional function, and environmental stimuli, providing a comprehensive assessment of asthma-related QoL. AQLQ scores are valuable for guiding asthma management and assessing the effectiveness of interventions. 37

38. Thank you 38