Using Rasch analysis to form plausible health states amenable to valuation: the development of CORE-6D from CORE-OM in order to elicit preferences for common mental health problems

Purpose: To describe a new approach for deriving a preference-based index from a condition specific measure that uses Rasch analysis to develop health states. Methods: CORE-OM is a 34-item instrument monitoring clinical outcomes of people with common mental health problems. CORE-OM is characterised by high correlation across its domains. Rasch analysis was used to reduce the number of items and response levels in order to produce a set of unidimensionally-behaving items, and to generate a credible set of health states corresponding to different levels of symptom severity using the Rasch item threshold map. Results: The proposed methodology resulted in the development of CORE-6D, a 2-dimensional health state description system consisting of a unidimensionally-behaving 5-item emotional component and a physical symptom item. Inspection of the Rasch item threshold map of the emotional component helped identify a set of 11 plausible health states, which, combined with the physical symptom item levels, will be used for the valuation of the instrument, resulting in the development of a preference-based index. Conclusions: This is a useful new approach to develop preference-based measures where the domains of a measure are characterised by high correlation. The CORE-6D preference-based index will enable calculation of Quality Adjusted Life Years in people with common mental health problems

HEDS Discussion Paper 09-15: Developing preference-based health measures: using Rasch analysis to generate health state values

Background/aims: Condition specific measures may not always have independent items, and existing techniques of developing health state values from these measures are inappropriate when items are not independent. This study develops methods for deriving and valuing health states for a preference-based measure. Methods: Three key stages are presented: Rasch analysis is used to develop a health state classification system and identify a set of health states for valuation. A valuation survey of the health states using time-trade-off (TTO) methods is conducted to elicit health state values. Finally, regression models are applied to map the relationship between mean TTO values and Rasch logit values. The model is then used to estimate health state values for all possible health states. Methods are illustrated using the Flushing Symptoms Questionnaire (FSQ). Results: Rasch models were fitted to 1270 responders to the FSQ and a series of 16 health states identified for the valuation exercise. An ordinary least squares model best described the relationship between mean TTO values and Rasch logit values. (R2 = 0.958; Root mean square error = 0.042). Conclusions: We have shown how the valuation of health states can be mapped onto the Rasch scale in order to value all states defined by the FSQ. This should significantly enhance work in this field

HEDS Discussion Paper 09-15: Developing preference-based health measures: using Rasch analysis to generate health state values

Background/aims: Condition specific measures may not always have independent items, and existing techniques of developing health state values from these measures are inappropriate when items are not independent. This study develops methods for deriving and valuing health states for a preference-based measure. Methods: Three key stages are presented: Rasch analysis is used to develop a health state classification system and identify a set of health states for valuation. A valuation survey of the health states using time-trade-off (TTO) methods is conducted to elicit health state values. Finally, regression models are applied to map the relationship between mean TTO values and Rasch logit values. The model is then used to estimate health state values for all possible health states. Methods are illustrated using the Flushing Symptoms Questionnaire (FSQ). Results: Rasch models were fitted to 1270 responders to the FSQ and a series of 16 health states identified for the valuation exercise. An ordinary least squares model best described the relationship between mean TTO values and Rasch logit values. (R2 = 0.958; Root mean square error = 0.042). Conclusions: We have shown how the valuation of health states can be mapped onto the Rasch scale in order to value all states defined by the FSQ. This should significantly enhance work in this field

Performance of Growing-Finishing Swine Under Different Environmental Conditions

The performance of growing-finishing pigs maintained in pens with different floor construction has been studied in two experiments (winter and summer). The four types of floor construction are: completely slotted, 5CY/o slotted, 25% slotted and a sloped concrete floor with a narrow gutter across the lower end of the pen. Pits under the slotted floors accumulate the manure. In addition to floor type, a comparison has been made of number of pigs per pen and controlled and uncontrolled house temperatures. Pen size was 5 x 15 feet when 8 or 9 pigs were used per pen and 10 x 15 feet when the pig numbers were doubled thus allowing the same number of square feet per pig. Feeder and water space per pig was also equalized between lots. During the winter trial two lots of pigs were also confined in an uninsulated house and bedded with straw. Feeders and waters were located inside of these houses. Identical rations were fed to all lots of pigs in both experiments. The composition of the rations fed are shown in Table 1

Loneliness, social relations and health and wellbeing in deprived communities

There is growing policy concern about the extent of loneliness in advanced societies, and its prevalence among various social groups. This study looks at loneliness among people living in deprived communities, where there may be additional barriers to social engagement including low incomes, fear of crime, poor services and transient populations. The aim was to examine the prevalence of loneliness, and also its associations with different types of social contacts and forms of social support, and its links to self-reported health and wellbeing in the population group. The method involved a cross-sectional survey of 4,302 adults across 15 communities, with the data analysed using multinomial logistic regression controlling for sociodemographics, then for all other predictors within each domain of interest. Frequent feelings of loneliness were more common among those who: had contact with family monthly or less; had contact with neighbours weekly or less; rarely talked to people in the neighbourhood; and who had no available sources of practical or emotional support. Feelings of loneliness were most strongly associated with poor mental health, but were also associated with long-term problems of stress, anxiety and depression, and with low mental wellbeing, though to a lesser degree. The findings are consistent with a view that situational loneliness may be the product of residential structures and resources in deprived areas. The findings also show that neighbourly behaviours of different kinds are important for protecting against loneliness in deprived communities. Familiarity within the neighbourhood, as active acquaintance rather than merely recognition, is also important. The findings are indicative of several mechanisms that may link loneliness to health and wellbeing in our study group: loneliness itself as a stressor; lonely people not responding well to the many other stressors in deprived areas; and loneliness as the product of weak social buffering to protect against stressors

The Presence of the Shelley's in the Brontës' Juvenilia

This thesis examines the juvenilia of the four Brontë siblings. It considers them primarily as readers, whose own work developed through their rewriting of the texts which they read. It proposes that, from 1829 onwards, a narrative about Percy Bysshe and Mary Shelley was available to the Brontë family through the periodicals and newspapers they had access to. It then shows how this narrative informed the writing of the juvenilia. To date, there has been no single, systematic exploration of a Shelleyean presence in the Brontës’ work. This thesis brings together scholars’ occasional and isolated recognitions of Shelleyean influences, alongside a wealth of new evidence, with the aim of demonstrating that the Brontës’ engagement with the Shelleys was more pervasive and significant than has hitherto been realised, and that the Brontës’ works should therefore be understood as having both a Shelleyean and also a specifically female literary heritage. Considering examples of well-known textual borrowings in the juvenilia, such as those involving Napoleonic or Byronic narratives, I define a writing framework within which the Shelleys might be placed. This writing model involved borrowing from a source text to create a new work, where those borrowings might be structural, thematic or linguistic. Giving consideration also to wider Romantic writing practices, I explain how this practice of borrowing from, and responding to, certain Shelleyean narratives was intended to be recognised by the reader. Drawing on Helen Small’s recognition of a slight linguistic parallel between Mary’s The Last Man and Emily’s Wuthering Heights, this thesis proposes that the work of all four siblings demonstrates linguistic and thematic similarities with that of the Shelley’s published lives, as well as with elements of their work and poetry. As both readers and writers, the Brontës were, it is argued, fully a product of, and fully engaged with, the print culture of their time

Estimating a preference-based single index from the Asthma Quality of Life Questionnaire (AQLQ)

This paper presents a study to estimate a preference-based single index from the Asthma Quality of Life Questionnaire (AQLQ). Based on the AQL-5D which is a health classification system directly derived from AQLQ, 98 health states were valued by a sample of 307 members of the UK general population. Models were estimated to predict all possible 3125 health states defined by the AQL-5D and compared using a set of criteria. The mean model of main effects was recommended of preferable prediction ability and logically consistent and significant coefficients for levels of dimensions. However, there are concerns over condition-specific valuation issues, such as presenting asthma information to general public and the choice of condition specific full health as the upper anchor for TTO valuation

Improving the measurement of QALYs in dementia: Developing patient- and carer-reported health state classification systems using Rasch analysis

Objectives: Cost-utility analysis is increasingly used to inform resource allocation. This requires a means of valuing health states before and after intervention. Although generic measures are typically used to generate values, these do not perform well with people with dementia. We report the development of a health state classification system amenable to valuation for use in studies of dementia, derived from the DEMQOL system, a measure of health-related quality of life in dementia by patient self-report (DEMQOL) and carer proxy-report (DEMQOL-Proxy). Methods: Factor analysis was used to determine the dimensional structure of DEMQOL and DEMQOL-Proxy. Rasch analysis was subsequently used to investigate item performance across factors in terms of item-level ordering, functioning across subgroups, model fit and severity-range coverage. This enabled the selection of one item from each factor for the classification system. A sample of people with a diagnosis of mild/moderate dementia (n=644) and a sample of carers of those with mild/moderate dementia (n=683) were used. Results: Factor analysis found different 5-factor solutions for DEMQOL and DEMQOL-Proxy. Following item reduction and selection using Rasch analysis, a 5-dimension classification for DEMQOL and a 4-dimension classification for DEMQOL-Proxy were developed. Each item contained 4 health state levels. Conclusion: Combining Rasch and classical psychometric analysis is a valid method of selecting items for dementia health state classifications from both the patient and carer perspectives. The next stage is to obtain preference weights so that the measure can be used in the economic evaluation of treatment, care and support arrangements for dementia