In medical decision making decisions are made by using cost-utility analyses. Utilities, in cost-utility analyses, are benefits in health estimated by comparing preferences for health states to... Show moreIn medical decision making decisions are made by using cost-utility analyses. Utilities, in cost-utility analyses, are benefits in health estimated by comparing preferences for health states to perfect health and death. Whose__ utilities are used, those given by patients__ or by members of the general public, does matter. Previous research has shown that utilities given by patients are higher compared to those given by members of the public. The main objective of this thesis was to examine mechanisms that have been suggested to explain this gap between health state utilities. Most mechanisms suggested to influence this gap were only marginally explanatory except for focusing illusion and adaption. The public has the tendency to focus on the negative aspects of a health state. On the other hand patients adapt to their illness and take this adaptation into account. Due to focusing illusion of members of the public utilities will become lower whereas adaptation will lead to higher utilities. Whose utilities should be used in decision making depends on whose utilities are most valid. Utilities shaped by focusing illusion are biased however it is a matter of discussion if adaptation leads to invalid utilities. Show less
BACKGROUND In cost-utility analyses gain in health can be measured using health state utilities. Health state utilities can be elicited from members of the public or from patients. Utilities given... Show moreBACKGROUND In cost-utility analyses gain in health can be measured using health state utilities. Health state utilities can be elicited from members of the public or from patients. Utilities given by patients tend to be higher than utilities given by members of the public. This difference is often suggested to be explained by adaptation, but this has not yet been investigated in patients. Here, we investigate if, besides health related quality of life (HRQL), persons' ability to adapt can explain health state utilities. Both the direct effect of persons' adaptive abilities on health state utilities and the indirect effect, where HRQL mediates the effect of ability to adapt, are examined. METHODS In total 125 patients with Rheumatoid Arthritis were interviewed. Participants gave valuations of their own health on a visual analogue scale (VAS) and time trade-off (TTO). To estimate persons' ability to adapt, patients filled in questionnaires measuring Self-esteem, Mastery, and Optimism. Finally they completed the SF-36 measuring HRQL. Regression analyses were used to investigate the direct and mediated effect of ability to adapt on health state utilities. RESULTS Persons' ability to adapt did not add considerably to the explanation of health state utilities above HRQL. In the TTO no additional variance was explained by adaptive abilities (Δ R2 = .00, β = .02), in the VAS a minor proportion of the variance was explained by adaptive abilities (Δ R2 = .05, β = .33). The effect of adaptation on health state utilities seems to be mediated by the mental health domain of quality of life. CONCLUSIONS Patients with stronger adaptive abilities, based on their optimism, mastery and self-esteem, may more easily enhance their mental health after being diagnosed with a chronic illness, which leads to higher health state utilities. Show less
Quality of life researchers have been studying "response shift" for a decade now, in an effort to clarify how best to measure QoL over time and across changing circumstances. However, we contend... Show moreQuality of life researchers have been studying "response shift" for a decade now, in an effort to clarify how best to measure QoL over time and across changing circumstances. However, we contend that this line of research has been impeded by conceptual confusion created by the term "response shift", that lumps together sources of measurement error (e.g., scale recalibration) with true causes of changing QoL (e.g., hedonic adaptation). We propose abandoning the term response shift, in favor of less ambiguous terms, like scale recalibration and adaptation. Show less
Objectives: To obtain quality-adjusted life-years, different respondent groups, such as patients or the general public, may be asked to value health states. Until now, it remains unclear if the... Show moreObjectives: To obtain quality-adjusted life-years, different respondent groups, such as patients or the general public, may be asked to value health states. Until now, it remains unclear if the respondent group has an influence on the values obtained. We assessed this issue through meta-analysis. Methods: A literature search was performed for studies reporting valuations given by patients and nonpatients. Studies using indirect utility instruments were excluded. Results: From 30 eligible studies, 40 estimators were retrieved revealing a difference between respondent group (Cohen's d = 0.20, P < 0.01). When elicitation methods were analyzed separately, patients gave higher valuations than nonpatients using the time trade-off (TTO) (N = 25, unstandardized d = 0.05, P < 0.05) and the visual analog scale (VAS) (N = 22, unstandardized d = 0.04, P < 0.05). When the standard gamble was used, no difference was seen (N = 24, unstandardized d = 0.01, P = 0.70). Conclusion: In contrast with Dolders et al., our results show that patients give higher valuations than members of the general public. For future cost-utility analyses, researchers should be aware of the differential effects of respondent group for the elicitation methods TTO and VAS. Show less
