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.quality adjusted life years; health related quality of life; Rasch analysis; preference-based measures of health; health states; dementia

Psychometric properties of the Stroke and Aphasia Quality of Life Scale (SAQOL-39) in a generic stroke population

Background: We previously developed the Stroke and Aphasia Quality of Life scale (SAQOL-39) and tested it with people with chronic aphasia. A scale allowing comparisons of quality of life between people with versus without aphasia post-stroke would be of value to clinicians. Objectives: To evaluate the psychometrics of the SAQOL-39 in a generic stroke sample. Should this process result in a generic-stroke version of the scale (SAQOL-39g), a further aim is to compare the latter and the SAQOL-39 as tested in chronic aphasia. Design and subjects: Repeated measures psychometric study, evaluating internal consistency, test—retest reliability, construct validity and responsiveness to change. People admitted to hospital with a first stroke were assessed two weeks, three months and six months post stroke. Measures: SAQOL-39, National Institutes of Health Stroke Scale, Barthel, Frenchay Aphasia Screening Test, General Health Questionnaire-12 and Frenchay Activities Index. Results: Of 126 eligible participants, 96 (76%) participated and 87 (69%) were able to self-report and are presented here. Testing the SAQOL-39 in generic stroke resulted in the SAQOL-39g, which has the same items as the SAQOL-39 but three domains: physical, psychosocial, communication. The SAQOL-39g showed good internal consistency (α = 0.95 overall score, 0.92—0.95 domains), test—retest reliability (interclass correlation (ICC) = 0.96 overall, 0.92—0.98 domains), convergent (r = 0.36—0.70 overall, 0.47—0.78 domains) and discriminant validity (r = 0.26 overall, 0.03—0.40 domains). It differentiated people by stroke severity and visual analogue scale (VAS)-defined quality of life. Moderate changes (d = 0.35—0.49; standardized response mean (SRM) = 0.29—0.53) from two weeks to six months supported responsiveness. Conclusions: The SAQOL-39g demonstrated good reliability, validity and responsiveness to change. It can be used to evaluate quality of life in people with and without aphasia post stroke

Supervised exercise training as an adjunctive therapy for venous leg ulcers: study protocol for a randomised controlled trial

Background: Venous leg ulcers are common, chronic wounds that are painful and reduce quality of life. Compression therapy is known to assist in the healing of venous leg ulceration. Supervised exercise training that targets an improvement in calf muscle pump function might be a useful adjunctive therapy for enhancing ulcer healing and other aspects of physical and mental health. However, the evidence of exercise for individuals with venous ulcers is sparse. Here, we describe the protocol for a study that aims to assess the feasibility of undertaking a randomised controlled trial of a supervised exercise programme in people who are receiving compression for venous ulceration. Methods/Design: This is a randomised, controlled, assessor-blinded, two-centre, feasibility trial with two parallel groups. Eighty adults who are receiving lower-limb compression for a venous leg ulcer will be randomly assigned to receive usual care (compression only) or usual care plus a 12-week supervised exercise programme. Participants in the exercise group will be invited to undertake three, 60-minute sessions of supervised exercise each week, and each session will involve a combination of treadmill walking, upright cycling and strength and flexibility exercises for the lower limbs. Participants will be assessed before randomisation and 3, 6 and 12 months after randomisation. Primary outcomes include rates of recruitment, retention and adherence. Secondary outcomes include time to ulcer healing, proportion of participants healed, percentage and absolute change in ulcer size, health-related quality of life (EQ-5D-5L and VEINES-QOL/Sym), lower-limb cutaneous microvascular function (laser Doppler flowmetry coupled with iontophoresis) and physical fitness (30-second sit-to-stand test, chair sit and reach test, 6-minute walk test and ankle range of motion). The costs associated with the exercise programme and health-care utilisation will be calculated. We will also complete interviews with a sub-sample of participants to explore their experiences of having a venous ulcer and the acceptability of the exercise intervention and study procedures. Discussion: Data from this study will be used to refine the supervised exercise programme, investigate the acceptability of the intervention and study design and determine the most appropriate outcome measures, thereby providing estimates of the factors needed to design an adequately powered trial across several centres

Quality of life after stroke: Evaluation of the Greek SAQOL-39g

Background/Aims: Stroke and aphasia rehabilitation aims to improve people’s quality of life. Yet, scales for measuring health-related quality of life in stroke typically exclude people with aphasia. They are also primarily available in English. An exception is the Stroke and Aphasia Quality of Life scale (SAQOL-39g). This scale has been tested with people with aphasia; it has been adapted for use in many countries including Greece. The aim of this study was to examine the psychometric properties of the Greek SAQOL-39g. Methods: An interview-based psychometric study was carried out. Participants completed: receptive sub-tests of Frenchay Aphasia Screening Test, Greek SAQOL-39g, General Health Questionnaire-12, Frenchay Activities Index, Montreal Cognitive Assessment and Barthel Index. Results: 86 people took part; 26 provided test-retest reliability data. The Greek SAQOL-39g demonstrated excellent acceptability (minimal missing data; no floor/ceiling effects), test-retest reliability (ICC= 0.96 scale, 0.83-0.99 domains) and internal consistency (Cronbach’s alpha 0.96 scale, 0.92-0.96 domains). There was strong evidence for convergent (r=0.53-0.80 scale; 0.54-0.89 domains) and discriminant validity (r=0.52 scale; 0.04-0.48 domains). Conclusion: The Greek SAQOL-39g is a valid and reliable scale. It is a promising measure for use in stroke and aphasia treatment prioritization, outcome measurement and service evaluation

Evaluating Psychometric Properties of an Instrument Addressing Comprehensiveness of Care Among Dentists

Universidade Federal de Minas Gerais. Departamento de Odontologia Comunitária e Preventiva. Belo Horizonte, MG, Brazil.Fundação Oswaldo Cruz. Instituto René Rachou. Belo Horizonte, MG, Brazil.Division of Population and Patient Health. King’s College London Dental Institute at Guy’s. King’s College and St Thomas’ Hospitals. London, UK.Universidade Federal de Minas Gerais. Departamento de Ortodontia e Odontopediatria Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Departamento de Odontologia Comunitária e Preventiva. Belo Horizonte, MG, Brazil.Objetivou-se avaliar as propriedades psicométricas de um instrumento para avaliar a integralidade do cuidado por dentistas, usando uma combinação da teoria clássica e teoria da resposta ao item. Um instrumento com 46 itens foi desenvolvido e testado por um painel de experts, seguido por um teste piloto e aplicação em 187 dentistas da atenção primária de uma grande cidade brasileira. Os seguintes critérios foram utilizados para avaliar os 46 itens: aceitabilidade, consistência interna, estabilidade temporal, correlação inter-item e correlação tetracórica. Essa avaliação resultou em uma versão reduzida de 11 itens que preencheram todos os critérios descritos acima. A estabilidade temporal foi medida utilizando o Cohen Kappa. Os 11 itens apresentaram valores maiores que 0,5. O alfa de Cronbach foi de 0,72. Nenhum dos 11 itens apresentou perda na distribuição das respostas, e o modelo que considera a discriminação como variante se adequa melhor aos dados do que o modelo que considera a discriminação como um parâmetro constante (p <0,001). Curvas características mostraram que 54,5% dos itens pode ser considerado difícil, ou seja, apenas os dentistas com uma boa compreensão da integralidade respondeu favoravelmente. O instrumento de 11 itens para avaliar a integralidade do cuidado por dentistas é considerado como tendo boas propriedades psicométricas.This study aimed to evaluate the psychometric properties of an instrument to assess comprehensiveness of care from dentists using a combination of classical test theory and item response theory. A 46-item instrument was developed and tested by a panel of experts, followed by a pilot test and administration to 187 primary care dentists in a large Brazilian city. The 46 items were evaluated using the following criteria: acceptability, internal consistency, temporal stability, inter-item correlation, and tetrachoric correlation. This evaluation led to a shortened version consisting of 11 items that met all the criteria previously described. The temporal stability was measured using Cohen’s kappa, and all 11 items presented values greater than 0.5. The Cronbach’s alpha value was 0.72. None of the 11 items had missing data on the distribution of responses, and the model considering the discrimination as varying fit the data better than the model considering discrimination as a constant parameter (p<0.001). Item characteristic curves showed that 54.5% of items could be considered difficult, i.e., only dentists with a good understanding of comprehensiveness responded favorably. The 11-item instrument to assess comprehensiveness of care by dentists is considered to have good psychometric properties

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