Impacts of Food Hypersensitivities on Quality of Life in the UK and Willingness to Pay (WTP) to remove those impacts
Appendix M Subjective Perception of Illness: Results
We used an additional measure of the impact of respondent’s food hypersensitivity on their quality of life (in addition to the EQ5D, EQ-VAS and FAQLQ, FIQLQ and CDQ measures), namely a subjective perception of illness scale.
We required an established instrument which was also concise and hence adopted the widely cited Brief Illness Perception Questionnaire (Brief IPQ) (Broadbent at al., 2006) which uses 9 questions on a single, 11-point, scale.
The data collected sing this scale was not used in the choice models analysed since the EQ-VAS and FAQLQ / FIQLQ / CDQ proved highly effective in explaining heterogeneity in preferences.
For completeness, we report descriptive information about the distribution of those Brief IPQ scores among the adult sample.
How much does your condition affect your life?
The bar chart shows the distribution of responses to the Subjective Perception of Illness question: ‘How much does your condition affect your life?’. When asked ‘how much does you condition affect your life?’ around 80% of respondents provided a score of 5 or more.
How long do you think your condition will continue?
The bar chart shows the distribution of responses to the Subjective Perception of Illness question: How long do you think your condition will continue? When asked ‘how long do you think your condition will continue?’ almost 90% of respondents said forever.
How much control do you feel you have over your condition?
The bar chart shows the distribution of responses to the Subjective Perception of Illness question: ‘how much control do you feel you have over your condition? When asked ‘how much control do you feel you have over your condition?’ around 80% of respondents provided a score of 5 or more, whereby 0 is no control and 11 is complete control.
How much do you think treatment can help your condition?
The bar chart shows the distribution of responses to the Subjective Perception of Illness question: ‘how much control do you think treatment can help your condition?’ When asked ‘how much control do you think treatment can help your condition?’ around 25% of respondents indicted ‘no help at all’ (score 0), 15% of respondents gave a score of 6 and around 12% of respondents indicated ‘completely help my condition (score 11).
How much do you experience symptoms from your condition?
The bar chart shows the distribution of responses to the Subjective Perception of Illness question: ‘how much do you experience symptoms from your condition?’ When asked ‘how much do you experience symptoms from your condition?’ almost 15% of respondents indicated score 6 whereby 0 is ‘no symptoms at all’ and score 11 is ‘severely affects my life’.
How concerned are you about your condition?
The bar chart shows the distribution of responses to the Subjective Perception of Illness question: ‘how concerned are you about your condition?’
How well do you feel you understand your condition?
The bar chart shows the distribution of responses to the Subjective Perception of Illness question: ‘well do you feel you understand your condition?’
How much does your condition affect you emotionally? (for example, does it make you angry, scared, upset or depressed?)
The bar chart shows the distribution of responses to the Subjective Perception of Illness question: ‘How much does your condition affect you emotionally?’