15D: Strengths, weaknesses and future development

Transcription

1 15D: Strengths, weaknesses and future development Harri Sintonen University of Helsinki and FinOHTA Definition of health-related quality of life HRQoL instruments usually try, as does the 15D, to cover the WHO aspects of health: physical (functioning of the psycho-physical system) mental/experiential social (social functioning in usual roles and tasks) The instruments differ in how they operationalise these aspects (i.e., convert them into measurable variables) 1

2 Criteria for choosing an HRQoL instrument for economic evaluation (costutility analysis) To maximise the effectiveness of health care with the limited resources available, HRQoL should be measured commensurably, with a common currency, i.e., with a generic HRQoL instrument, which - allows comparisons across different diseases and health problems, and - combines the advantages of a single index number instrument and of a profile instrument - produces HRQoL scores suitable for QALY calculations Components of an HRQoL instrument for economic evaluation Two components: A standardised health state descriptive system (the measurable dimensions of health and their levels) A valuation system for valuing the health states defined by the descriptive system The instruments differ in both respects 2

3 The 15D health state descriptive system: dimensions Breathing Mental function Communication (speech) Vision Mobility Usual activities Hearing Eating Elimination Sleeping Distress Disfomfort and symptoms Sexual activity Depression Vitality The 15D health state descriptive system: The dimension levels Each dimension divided into 5 levels, by which more or less of the attribute is distinguished 3

4 The levels of the breathing dimension Level value 1. I am able to breathe normally, i.e. with no shortness of breath or other breathing difficulty I have shortness of breath during heavy work or sports or when walking briskly on flat ground or slightly uphill I have shortness of breath when walking on flat ground at the same speed as others my age I get shortness of breath even after light activity, e.g. washing or dressing myself I have breathing difficulties almost all the time, even when resting.093 Properties of the 15D health state descriptive system FEASIBILITY AND GENERAL APPLICABILITY Completion time (one level ticked from each dimension): 5-10 minutes Reception and acceptance: response and completion rates high (as high as those for EQ- 5D) 4

5 Properties of the 15D health state descriptive system RELIABILITY (repeatability of measurements with a minimum of random error = test-retest) Repeatability coefficients (Bland & Altman 1986) high (92-100% depending on dimension) No significant difference between the instruments Properties of the 15D health state descriptive system VALIDITY (degree of confidence that can be placed in the inferences drawn from the scores of a measure) No gold standard Content validity: 15D more comprehensive in content than comparable instruments 15D covers almost one-to-one the most important domains of health as defined in WHO Disc. Paper 45 5

6 Properties of the 15D health state descriptive system Content validity (cont d): 15D covers over 80 % of the domains in the new International Classification of Functioning, Disability and Health (ICF) by the WHO EQ-5D covers 20 % of the domains in the ICF ICF vs. 15D conceptually WHO Disc. Paper 45 15D Vision Vision Hearing Hearing Speaking Speech Digestion Elimination Bodily excretion Elimination Fertility? Sexual functioning Sexual activity Skin and disfigurement Discomfort and symptoms Breathing Breathing Pain Discomfort and symptoms Affect Depression, Distress Sleep Sleeping Energy and vitality Vitality Cognition Mental function Communication Speech Mobility Mobility Dexterity? Self-care Eating Usual activities Usual activities Interpersonal relations? Social functioning Usual activities Participation Usual activities 6

7 Properties of the 15D health state descriptive system SENSITIVITY A. Discriminatory power = ability to distinguish between individuals and groups in different health states cross-sectionally 15D theoretically very sensitive (defines an enormous number of different health states) Properties of the health state descriptive system: 15D vs. EQ-5D SENSITIVITY A. Discriminatory power (empirically e.g. in terms of ceiling and floor effects) on comparable dimensions and considering the measure as a whole: - 15D clearly better than EQ, e.g patients prior to CABG or PTCA: EQ-5D: 15 % in full health, 15D: none (Kattainen 2004) - Representative Finnish population sample aged 30 years+: EQ-5D: 47 % in full health, 15D: 15 % - People with one of 29 chronic diseases/conditions: EQ-5D: 6-39 % in full health, 15D: 1-11 % 7

8 Properties of the 15D health state descriptive system SENSITIVITY B. Responsiveness to change (ability to detect changes in individuals or groups over time) on comparable dimensions and considering the measure as a whole: - 15D clearly more responsive than EQ, e.g. - 6 months after CABG or PTCA: According to 15D score: 79 % improved; EQ score: 51 % (Kattainen et al. 2005) - Clearly higher effect sizes and responsiveness statistics than EQ in the treatment COPD and rehabilitation of musculosceletal, cardiovascular ja psychosomatic disorders (Moock and Kohlman 2005) 1 Hip replacement 15D score before treatment = D score 3 months after treatment = before 3 months after 0,9 0,8 0,7 0,6 0,5 MOVE SEE HEAR BREATH SLEEP EAT COMM ELIM UACT MENTAL PAIN DEPR DISTR VITAL SEX 8

9 Level value The 15D profile of the UI (urinary incontinence) patients before and after treatment and the profile of the agematched general population (Stach-Lempinen et al. 2004) 1 0,9 0,8 0,7 0,6 0,5 0,4 0,3 Move See Hear Breath Sleep Eat Speech Elim Uact Mental Disco Depr Distr Vital Sex 15D score Before After Popul Before After Popul The mean 15D scores and profiles of CABG and PTCA patients at baseline and at 6 months after treatment, and of ageand gender-matched general population (Kattainen et al. 2005) Level value D scores CABG0 = PTCA0 = POPUL = CABG6 = PTCA6 = CABG0 0.5 PTCA Move See Hear Breath Sleep Eat Speech Elim Uact Dimensions Vital Mental Disco Depr Distr Sex POPUL CABG6 PTCA6 9

10 Properties of the 15D health state valuation system Based on the multi-attribute utility theory Total score over all the dimensions (v H ) through a 3-stage additive valuation procedure: v = I H j j v (x )[w(x )] where I j (x j ) = the average relative importance people attach to various levels of dimension j (j = 1, 2,..,15), w j (x j ) = the average value people place on various levels of dimension j j j j Properties of the 15D health state valuation system Max 15D score = 1 (no problems on any dimension) Min score = 0 (being dead) Importance weights and level values elicited with RS/ME (ratio scale with quantifiers) from representative population samples Duration of states to be valued: unspecified/uncertain 10

11 Properties of the 15D health state valuation system Reliability = repeatability and stability at group level Correlations between averaged sets of importance weights from population samples: rank correlations Pearson correlations Also regression tests indicated that the agreement is quite good => Reliability at the group level thus good Properties of the 15D health state valuation system Validity: No gold standard To be valid for QALY calculations, the values should reflect a reasonable trade-off between quality and length of life The 15D scores appear to perform quite well in this respect (Nord) => further evidence later on Practically/clinically important change in 15D score:$*0.03* 11

12 Areas of application/uses of the 15D Assessment of effectiveness and efficiency (cost-utility) of health care technologies/programs Comparison of the HRQoL and QALYs of population by regions/groups and over time Setting output objectives for hospitals/clinics/wards and measuring their output Standardisation of patient-mix in comparing and analysing the productivity of hospitals/clinics/wards Improvement of clinical decision making using as a diagnostic tool a standard measure as a part of medical records 15D: Strengths Generic Comprehensive in contents Sensitive both in terms of - discriminatory power and - responsiveness to change Easy-to-use (self-administered) Combines the advantages of a profile and single index score instrument Applicable for various purposes In valuation the duration of states unspecified/uncertain as is the case in reality Credible scores = comply with common sense 12

13 15D: Weaknesses Slightly longer completion time than e.g. for EQ-5D Finnish origin a problem? Richardson et al. (1999) recommendation: 15D is given a lower priority as its utility scores are elicited in a choiceless context and the aggregation is based on an additive multi-attribute model => Is this recommendation warranted? Valuations so far from two countries (Finland and Denmark: almost identical valuations), but is it a problem in the light of the conclusion from the EuroQol project? Conclusion from the EuroQol Project There is a considerable degree of agreement between health state valuations from several European countries. Hence in Western industrialised countries it appears unnecessary to replicate expensive valuation studies in each country in order to arrive at valid preference-based HRQoL instruments (Sintonen et al. 2003) 13

14 Developments with the 15D Question to be answered: Is the original 15D valuation algorithm still valid at present (9 years after it was elicited)? Original valuations elicited in 1992 New data were collected with identical methodology in 2001 The valuation algorithm based on the 2001 data produces almost identical 15D scores and profiles as the 1992 algorithm => the 1992 algorithm still valid Developments with the 15D Question to be answered: What is the relationship between the 15D scores and quality of life scores elicited with different valuation methods? Data from about 900 patients from 14 specialties with different illnesses at different levels of severity => The relationship between Time Trade-Off (TTO) scores of patients own health states and their 15D scores is linear and the agreement between them at the aggregate level good 14

15 The relationship of TTO valuations of patients of their own health status and 15D scores: To the extent that the former are valid for QALY calculations, then are also the 15D scores without any transformation 1.0 PRED1 DIAGONAL D15SCORE Developments with the 15D Question to be answered: Which HRQoL instrument (15D, HUI3, EQ-5D/TTO, EQ-5D/VAS, AQoL, SF-6D) produces on average scores, which reflect best the direct TTO valuations of general population of their own health status in different age groups? Population survey with a representative sample 4000 individuals across 8 age groups of both genders (n=250 per age and gender group 17-24,, 85+) 15

16 Developments with the 15D Preliminary results 15D reflects best => to the extent that TTO valuations of general population on their own health states are valid, the 15D scores are most valid for QALY calculations => The recommendation by Richardson et al. (1999) is unwarranted (which they have shown themselves later) The mean HRQoL scores with different instruments in various age groups:females 1 0,9 0,8 0,7 0,6 TTOown 15D HUI EQ SF-6D 0,5 0,4 17_24 25_34 35_44 45_54 55_64 65_74 75_

17 Developments with the 15D 15D website under construction Electronic versions (internet, mobile phone) for data collection, score calculation, profile production and basic statistical analysis under construction An ongoing extensive experiment in order to create a system for routine follow-up of effectiveness (measured by the 15D) and costs of treatment in Helsinki and Uusimaa Hospital District (about patients being followed-up) => 15D a part of medical records in the whole country? Versions 15D for age groups 16+ years For a detailed description and properties, see Sintonen H, NCHPE Working Papers 41 and 42, best available as.pdffiles on website Sintonen H. The 15D instrument of health related quality of life: Properties and applications. Ann Med 2001; 33: Available so far in 17 languages: Finnish, English, French, German, Swedish, Danish, Norwegian, Estonian, Russian, Japanese, Greek, Czech, Arabic, Hebrew, Serbian, Turkish, Icelandic 17

18 Versions 16D for age group years 17D for age group 8-11 years see Apajasalo et al. Qual Life Res 5, 1996, and 5, 1996, Both available in Finnish and English only (Swedish translation in progress) Inquiries/Use permissions: 18