The effect of disease adaptation information on general population values : a case study using rheumatoid arthritis states.

Objective: The Washington Panel on Cost-effectiveness in Health and Medicine recommends that economic evaluation of healthcare technologies uses values for health states elicited from the general population rather than patients. However, general population respondents do not necessarily recognize the possibility of adapting to the impaired state. This thesis examines how informing the general population about disease adaptation influences their values. Rheumatoid arthritis (RA) states are used as an illustration. Methods: This work employed a sequential mixed-methods design using three components. First, Rasch and cluster analyses were used to construct RA states. Simultaneously, a novel adaptation exercise consisting of audio-recordings of patients discussing disease adaptation was developed. Second, semi-structured interviews were conducted with 12 general population respondents to identify the effect of adaptation information on their perceptions of RA. Finally, the influence of this information on health state values from a random sample of the general population (n = 200) was assessed quantitatively and the factors contributing to this change were identified. Results: The first component of this study defined three RA states. In the second, the qualitative interviews revealed that the adaptation exercise encouraged the general population to empathize with the messages in the audio-recordings. Finally, the third component showed that the adaptation exercise was effective at changing health state values; for example, for the severe RA state, a mean (standard deviation) change of 0.17 (0.34) (p < 0.01) was observed. Individuals who were younger, were healthier, recognized the importance of coping strategies, and comprehended the valuation task were more likely to increase their values. Conclusions: The results from this thesis demonstrate a novel method of informing the general population about disease adaptation. After undertaking the adaptation exercise, most respondents increased their values for the given health states. Thus, important contributions are made to an emerging field of developing better informed general population values.