Combining Rasch and cluster analysis: a novel method for developing rheumatoid arthritis states for use in valuation studies

Purpose: Health states that describe an investigated condition are a crucial component of valuation studies. The health states need to be distinct, comprehensible, and data-driven. The objective of this study was to describe a novel application of Rasch and cluster analyses in the development of three rheumatoid arthritis health states. Methods: The Stanford Health Assessment Questionnaire (HAQ) was subjected to Rasch analysis to select the items that best represent disability. K-means cluster analysis produced health states with the levels of the selected items. The pain and discomfort domain from the EuroQol-5D was incorporated at the final stage. Results: The results demonstrate a methodology for reducing a dataset containing individual disease-specific scores to generate health states. The four selected HAQ items were bending down, climbing steps, lifting a cup to your mouth, and standing up from a chair. Conclusions: Overall, the combined use of Rasch and cluster analysis has proved to be an effective technique for identifying the most important items and levels for the construction of health states

Combining Rasch and cluster analysis: a novel method for developing rheumatoid arthritis states for use in valuation studies

Purpose: Health states that describe an investigated condition are a crucial component of valuation studies. The health states need to be distinct, comprehensible, and data-driven. The objective of this study was to describe a novel application of Rasch and cluster analyses in the development of three rheumatoid arthritis health states. Methods: The Stanford Health Assessment Questionnaire (HAQ) was subjected to Rasch analysis to select the items that best represent disability. K-means cluster analysis produced health states with the levels of the selected items. The pain and discomfort domain from the EuroQol-5D was incorporated at the final stage. Results: The results demonstrate a methodology for reducing a dataset containing individual disease-specific scores to generate health states. The four selected HAQ items were bending down, climbing steps, lifting a cup to your mouth, and standing up from a chair. Conclusions: Overall, the combined use of Rasch and cluster analysis has proved to be an effective technique for identifying the most important items and levels for the construction of health states.health state; Rasch analysis; cluster analysis; quality of life; rheumatoid arthritis

A qualitative study exploring the general population's perception of rheumatoid arthritis after being informed about disease adaptation

Purpose: This study aimed to gain an understanding of what factors induce individuals to alter their opinions about a health condition after being informed about disease adaptation and being given time to reflect and deliberate on this information. Rheumatoid arthritis (RA) states are used as an illustration. Methods: Semi-structured interviews were conducted with 12 members of the general population. They completed two time trade-off exercises for three RA states and underwent an adaptation exercise (AE) which consisted of listening to recordings of patients discussing how they adapted to RA. Also included was a structured discussion to encourage the participant to reflect on how the patients have adapted. Participants were shown their own health state values, as well as patient values. Findings: After being informed about disease adaptation and reflecting on the information, participants were more likely to consider adaptation and alter their opinions of RA if they were able to empathise with the patients in the AE. This enabled individuals to feel that they could cope by reflecting on their experience of RA in family and friends, by drawing on others for support if they had RA, and by having a positive attitude towards life. Conclusions: The results demonstrate that there is a range of reasons for which people change their perceptions about RA; this requires further exploration

A qualitative study exploring the general population's perception of rheumatoid arthritis after being informed about disease adaptation

Purpose: This study aimed to gain an understanding of what factors induce individuals to alter their opinions about a health condition after being informed about disease adaptation and being given time to reflect and deliberate on this information. Rheumatoid arthritis (RA) states are used as an illustration. Methods: Semi-structured interviews were conducted with 12 members of the general population. They completed two time trade-off exercises for three RA states and underwent an adaptation exercise (AE) which consisted of listening to recordings of patients discussing how they adapted to RA. Also included was a structured discussion to encourage the participant to reflect on how the patients have adapted. Participants were shown their own health state values, as well as patient values. Findings: After being informed about disease adaptation and reflecting on the information, participants were more likely to consider adaptation and alter their opinions of RA if they were able to empathise with the patients in the AE. This enabled individuals to feel that they could cope by reflecting on their experience of RA in family and friends, by drawing on others for support if they had RA, and by having a positive attitude towards life. Conclusions: The results demonstrate that there is a range of reasons for which people change their perceptions about RA; this requires further exploration

A qualitative study exploring the general population’s perception of rheumatoid arthritis after being informed about disease adaptation

Purpose: This study aimed to gain an understanding of what factors induce individuals to alter their opinions about a health condition after being informed about disease adaptation and being given time to reflect and deliberate on this information. Rheumatoid arthritis (RA) states are used as an illustration. Methods: Semi-structured interviews were conducted with 12 members of the general population. They completed two time trade-off exercises for three RA states and underwent an adaptation exercise (AE) which consisted of listening to recordings of patients discussing how they adapted to RA. Also included was a structured discussion to encourage the participant to reflect on how the patients have adapted. Participants were shown their own health state values, as well as patient values. Findings: After being informed about disease adaptation and reflecting on the information, participants were more likely to consider adaptation and alter their opinions of RA if they were able to empathise with the patients in the AE. This enabled individuals to feel that they could cope by reflecting on their experience of RA in family and friends, by drawing on others for support if they had RA, and by having a positive attitude towards life. Conclusions: The results demonstrate that there is a range of reasons for which people change their perceptions about RA; this requires further exploration.health state valuation; qualitative research; quality of life; disease adaptation

Combining Rasch and cluster analysis: a novel method for developing rheumatoid arthritis states for use in valuation studies

Purpose: Health states that describe an investigated condition are a crucial component of valuation studies. The health states need to be distinct, comprehensible, and data-driven. The objective of this study was to describe a novel application of Rasch and cluster analyses in the development of three rheumatoid arthritis health states. Methods: The Stanford Health Assessment Questionnaire (HAQ) was subjected to Rasch analysis to select the items that best represent disability. K-means cluster analysis produced health states with the levels of the selected items. The pain and discomfort domain from the EuroQol-5D was incorporated at the final stage. Results: The results demonstrate a methodology for reducing a dataset containing individual disease-specific scores to generate health states. The four selected HAQ items were bending down, climbing steps, lifting a cup to your mouth, and standing up from a chair. Conclusions: Overall, the combined use of Rasch and cluster analysis has proved to be an effective technique for identifying the most important items and levels for the construction of health states

Combining Rasch and cluster analysis: a novel method for developing rheumatoid arthritis states for use in valuation studies

Purpose: Health states that describe an investigated condition are a crucial component of valuation studies. The health states need to be distinct, comprehensible, and data-driven. The objective of this study was to describe a novel application of Rasch and cluster analyses in the development of three rheumatoid arthritis health states. Methods: The Stanford Health Assessment Questionnaire (HAQ) was subjected to Rasch analysis to select the items that best represent disability. K-means cluster analysis produced health states with the levels of the selected items. The pain and discomfort domain from the EuroQol-5D was incorporated at the final stage. Results: The results demonstrate a methodology for reducing a dataset containing individual disease-specific scores to generate health states. The four selected HAQ items were bending down, climbing steps, lifting a cup to your mouth, and standing up from a chair. Conclusions: Overall, the combined use of Rasch and cluster analysis has proved to be an effective technique for identifying the most important items and levels for the construction of health states

Effects of hydrogen addition on high-pressure nonpremixed natural gas combustion

The effects of hydrogen addition on the ignition and combustion of a high-pressure methane jet in a quiescent charge of high-temperature, medium-pressure air were investigated numerically and experimentally. Subsequently, the results of these two fundamental studies were applied to the interpretation of combustion and emissions measurements from a pilot-ignited natural gas engine fueled with similar fuels. Whereas, under quiescent conditions, the influence of hydrogen addition on the autoignition delay time of the gaseous jet was small, a markedly greater effect was observed in the more complex environment of the research engine. Similarly, in the two fundamental studies, the addition of hydrogen to the methane fuel resulted in a reduction of NOx emissions, whereas increased levels of NOx emissions were observed from the engine, highlighting the difference between the autoignition and pilot-ignition process

A qualitative study exploring the general population’s perception of rheumatoid arthritis after being informed about disease adaptation

Purpose: This study aimed to gain an understanding of what factors induce individuals to alter their opinions about a health condition after being informed about disease adaptation and being given time to reflect and deliberate on this information. Rheumatoid arthritis (RA) states are used as an illustration. Methods: Semi-structured interviews were conducted with 12 members of the general population. They completed two time trade-off exercises for three RA states and underwent an adaptation exercise (AE) which consisted of listening to recordings of patients discussing how they adapted to RA. Also included was a structured discussion to encourage the participant to reflect on how the patients have adapted. Participants were shown their own health state values, as well as patient values. Findings: After being informed about disease adaptation and reflecting on the information, participants were more likely to consider adaptation and alter their opinions of RA if they were able to empathise with the patients in the AE. This enabled individuals to feel that they could cope by reflecting on their experience of RA in family and friends, by drawing on others for support if they had RA, and by having a positive attitude towards life. Conclusions: The results demonstrate that there is a range of reasons for which people change their perceptions about RA; this requires further exploration

A qualitative study exploring the general population’s perception of rheumatoid arthritis after being informed about disease adaptation

Purpose: This study aimed to gain an understanding of what factors induce individuals to alter their opinions about a health condition after being informed about disease adaptation and being given time to reflect and deliberate on this information. Rheumatoid arthritis (RA) states are used as an illustration. Methods: Semi-structured interviews were conducted with 12 members of the general population. They completed two time trade-off exercises for three RA states and underwent an adaptation exercise (AE) which consisted of listening to recordings of patients discussing how they adapted to RA. Also included was a structured discussion to encourage the participant to reflect on how the patients have adapted. Participants were shown their own health state values, as well as patient values. Findings: After being informed about disease adaptation and reflecting on the information, participants were more likely to consider adaptation and alter their opinions of RA if they were able to empathise with the patients in the AE. This enabled individuals to feel that they could cope by reflecting on their experience of RA in family and friends, by drawing on others for support if they had RA, and by having a positive attitude towards life. Conclusions: The results demonstrate that there is a range of reasons for which people change their perceptions about RA; this requires further exploration