Mind the gap : explanations for the differences in utilities between respondent groups
Peeters, Y.
Citation
Peeters, Y. (2011, May 11). Mind the gap : explanations for the differences in
utilities between respondent groups. Retrieved fromhttps://hdl.handle.net/1887/17625
Version: Corrected Publisher’s Version
License: Licence agreement concerning inclusion of doctoral thesis in the Institutional Repository of the University of Leiden
Downloaded from: https://hdl.handle.net/1887/17625
Note: To cite this publication please use the final published version (if
applicable).
Colofon
ISBN: 978-90-8570-745-5
Cover illustration : with help of Jan Edelaar Lay-out: with help of Janneke van der Niet Printed by: CPI wöhrmann print service
Mind the Gap:
Explanations for the differences in utilities between respondent groups.
PROEFSCHRIFT
ter verkrijging van
de graad van Doctor aan de Universiteit Leiden,
op gezag van de Rector Magnificus prof. mr. P. F. van der Heijden, volgens besluit van het College voor Promoties
te verdedigen op woensdag 11 mei 2011 klokke 15.00 uur
door
Yvette Peeters
geboren te Venlo in 1981
Promotiecommissie
Promotor: Prof. dr. A. M. Stiggelbout
overige leden: Prof. dr. A. V. Ranchor (Universitair Medisch Centrum Groningen) Prof. dr. M. A. G. Sprangers (Universiteit van Amsterdam) Prof. dr. P. A. Ubel (Duke University,USA)
Dr. T. P. M. Vliet Vlieland
The printing of this thesis was financially supported by the Department of Medical Decision Making of the LUMC and the Dutch Arthritis Association.
The work presented in this thesis was financially supported by the Netherlands Organization for Scientific Research NWO Innovational Research Incentives (grant number 917.56.356).
Watch with glittering eyes the whole world around you, because the greatest secrets are always hidden in the most unlikely places. Those
who don’t believe in the magic will never find it.
- Roald Dahl -
Contents
1 General Introduction 1
1.1 Cost-Utility analyses . . . 3
1.2 Public or patients’ preferences . . . 5
1.3 Mechanisms underlying the gap . . . 6
1.4 Objective and outline of the thesis . . . 9
2 Health State Valuations Compared 11 2.1 Introduction . . . 13
2.2 Methods . . . 13
2.2.1 Search and retrieval of studies . . . 13
2.2.2 Data extraction . . . 14
2.2.3 Statistical analyses . . . 14
2.3 Results . . . 15
2.3.1 Overall meta-analysis . . . 16
2.3.2 Meta-analysis of studies by estimation method . . . 16
2.4 Discussion . . . 19
3 Valuing Health 23 3.1 Introduction . . . 25
3.2 Methods . . . 27
3.2.1 Participants and procedures . . . 27
3.2.2 The interview . . . 27
3.2.3 Data analysis . . . 30
3.3 Results . . . 31
3.3.1 Valuations of own experienced health state . . . 31
3.3.2 Differences in ratings between patients based on the severity of their current health state . . . 33
3.3.3 Own enriched EQ-5D state description . . . 33
3.4 Discussion . . . 34
3.5 Conclusion . . . 36
4 Focusing illusion, adaptation and EQ-5D 37 4.1 Introduction . . . 39
4.2 Methods . . . 41
4.2.1 Patient subject recruitment . . . 41
4.2.2 Recruitment of members of the public . . . 41
CONTENTS
4.2.3 Data collection . . . 41
4.2.4 Coding . . . 42
4.2.5 Analysis of data . . . 43
4.3 Results . . . 44
4.3.1 Participants . . . 44
4.3.2 Patients vs. Public . . . 46
4.4 Discussion . . . 50
5 Utilities - patients, partners and public 55 5.1 Introduction . . . 57
5.2 Methods . . . 60
5.2.1 Participants and procedures . . . 60
5.3 The interview . . . 61
5.4 Results . . . 63
5.4.1 Participants . . . 63
5.4.2 Valuations of the three health states . . . 63
5.5 Discussion . . . 66
6 Effect of adaptive abilities on utilities 71 6.1 Introduction . . . 73
6.2 Methods . . . 75
6.2.1 Participants and design . . . 75
6.2.2 The interview . . . 76
6.2.3 Instruments . . . 76
6.2.4 Indicators for persons’ adaptive abilities . . . 77
6.2.5 Data analysis . . . 78
6.3 Results . . . 78
6.3.1 Creating a scale measuring persons’ ability to adapt . . . 79
6.3.2 Predicting utilities . . . 80
6.3.3 Adaptive ability as direct predictor of TTO and the VAS, over and above HRQL . . . 80
6.4 Discussion . . . 81
6.5 Conclusion . . . 83
7 The influence of time and adaptation 85 7.1 Introduction . . . 87
7.2 Methods . . . 90
7.2.1 Participants and procedures . . . 90 vi
CONTENTS
7.2.2 The interview . . . 91
7.2.3 Assessments . . . 91
7.2.4 Data Analysis . . . 92
7.3 Results . . . 93
7.3.1 Change in health state valuations for the own health and the impact of adaptation . . . 96
7.3.2 Change in patients’ valuations of the RA health state . . . . 97
7.4 Discussion . . . 97
7.5 Conclusion . . . 100
8 After adversity strikes 101 8.1 Introduction . . . 103
8.2 Study 1 . . . 105
8.2.1 Overview . . . 105
8.2.2 Participants . . . 105
8.2.3 Study measurements . . . 105
8.2.4 Results . . . 106
8.2.5 Discussion . . . 107
8.3 Study 2 . . . 109
8.3.1 Overview . . . 109
8.3.2 Participants . . . 110
8.3.3 Study design and measurements . . . 111
8.3.4 Results . . . 111
8.4 Discussion . . . 113
9 A plea for conceptual clarity 117 9.1 Introduction . . . 119
9.2 Two examples of response shift . . . 120
9.2.1 Viewing these case studies through the lens of response shift 121 9.3 Defining response shift . . . 122
9.3.1 Scale recalibration . . . 122
9.3.2 Change in values . . . 122
9.3.3 Reconceptualization . . . 123
9.4 Problems conceptualization response shift . . . 124
9.4.1 Connotation that response shift is always a threat to validity of self-reports . . . 124
9.4.2 Identification of response shift with the “Then Test” . . . 125 vii
9.4.3 Misinterpretation of the Then Test . . . 126
9.4.4 Lumping instead of splitting . . . 127
9.5 Where do we go from here? . . . 127
9.5.1 Use precise language . . . 128
9.5.2 Move beyond the Then Test . . . 128
9.5.3 More careful review of response shift research . . . 128
9.6 Concluding remarks . . . 129
10 Summary & General Discussion 131 10.1 Summary . . . 133
10.2 General Discussion . . . 136
10.2.1 Mechanisms underlying the gap between members of the pub- lic and patients . . . 136
10.2.2 Evaluating the results . . . 137
10.2.3 Policy implications . . . 140
10.2.4 Implications for patient decision making . . . 142
10.2.5 Future research . . . 143
11 Dutch summary 145
Appedix A - D 153
References 169
