Developing a questionnaire to determine the impact of self-management in diabetes: giving people with diabetes a voice.

BACKGROUND: The prevalence of diabetes mellitus (DM) is increasing dramatically, placing considerable financial burden on the healthcare budget of each country. Patient self-management is crucial for the control of blood glucose, which largely determines the chances of developing diabetes-related complications. Self-management interventions vary widely, and a method is required for assessing the impact of self-management. This paper describes the development of a questionnaire intended for use to measure the impact of self-management in diabetes. METHODS: An iterative development process was undertaken to identify the attributes of self-management using 5 steps. First, a literature review was undertaken to identify and understand themes relating to self-management of DM to inform a topic guide. Second, the topic guide was further refined following consultation with a Patient and Public Involvement group. Third, the topic guide was used to inform semi-structured interviews with patients with Type 1 DM (T1DM) and Type 2 DM (T2DM) to identify how self-management of DM affects individuals. Fourth, the research team considered potential attributes alongside health attributes from an existing measure (Diabetes Health Profile, DHP) to produce an instrument reflecting both health and self-management outcomes simultaneously. Finally, a draft instrument was tested in a focus group to determine the wording and acceptability. RESULTS: Semi-structured interviews were carried out with 32 patients with T1DM and T2DM. Eight potential attributes were identified: fear/worry/anxiety, guilt, stress, stigma, hassle, control, freedom, and feeling supported. Four of these self-management attributes were selected with four health attributes (mood, worry about hypos (hypoglycaemic episodes), vitality and social limitations) to produce the Health and Self-Management in Diabetes (HASMIDv1) questionnaire. CONCLUSIONS: HASMIDv1 is a short questionnaire that contains eight items each with four response levels to measure the impact of self-management in diabetes for both T1DM and T2DM. The measure was developed using a mixed-methods approach that involved semi-structured interviews with people with diabetes. The measure has high face validity. Ongoing research is being undertaken to assess the validity of this questionnaire for measuring the impact of self-management interventions in economic evaluation.

Are preferences over health states informed?

BACKGROUND: The use of preference-elicitation tasks for valuing health states is well established, but little is known about whether these preferences are informed. Preferences may not be informed because individuals with little experience of ill health are asked to value health states. The use of uninformed preferences in cost-effectiveness can result in sub-optimal resource allocation. The aim of this study was to pilot a novel method to assess whether members of the public are informed about health states they value in preference-elicitation tasks. METHODS: The general public was said to be informed if the expectations of the public about the effect of ill health on people's lives were in agreement with the experience of patients. Sixty-two members of the public provided their expectations of the consequences of ill health on five life domains (activities, enjoyment, independence, relationships, and avoiding being a burden). A secondary dataset was used to measure patient experience on those five consequences. RESULTS: There were differences between the expectations of the public and the experience of patients. For example, for all five life consequences the public underestimated the effects of problems in usual activities compared to problems in mobility. They also underestimated the effect of 'anxiety or depression' compared to physical problems on enjoyment of life and on the quality of personal relationships. CONCLUSIONS: This proof-of-concept study showed that it is possible to test whether preferences are informed. This study should be replicated using a larger sample. The findings suggest that preferences over health states in this sample are not fully informed because the participants do not have accurate expectations about the consequences of ill health. These uninformed preferences may not be adequate for allocation of public resources, and research is needed into methods to make them better informed.

Developing preference-based measures for diabetes: DHP-3D and DHP-5D.

AIMS: The aim of this study was to develop two diabetes-specific preference-based measures [the Diabetes Health Profile-3 Dimension (DHP-3D) and the Diabetes Health Profile-5 Dimension (DHP-5D)] for use in the calculation of Quality Adjusted Life Years, a key outcome in economic evaluation. These measures were based on the non-preference-based instrument the Diabetes Health Profile. METHODS: For DHP-3D, psychometric and Rasch analyses were used to develop a health state classification system based on the Diabetes Health Profile-18 (DHP-18). The DHP-5D added two dimensions to the DHP-3D to extend the range of impacts measured. Each classification system was valued by 150 general public respondents in the United Kingdom using Time Trade Off (TTO). Multivariate regression was used to estimate utility value sets. The matched dimensions across each measure were compared using z-score tests. RESULTS: The DHP-3D included three dimensions defined as mood, eating and social limitations, and the DHP-5D added dimensions defined as hypoglycaemic attacks and vitality. For both, the random effects generalized least squares regression model produced consistent value sets, with the DHP-3D and DHP-5D ranging from 0.983 (best state) to 0.717 (worst state), and 0.979 to 0.618 respectively. The addition of the two extra dimensions leads to significant differences for the more severe levels of each matched dimension. CONCLUSIONS: We have developed two diabetes-specific preference-based measures that, subject to psychometric assessment, can be used to provide condition-specific utility values to complement generic utilities from more widely validated measures such as the EuroQol-5 Dimension.

The cost-effectiveness of changes to the care pathway used to identify depression and provide treatment amongst people with diabetes in England: a model-based economic evaluation.

BACKGROUND: Diabetes is associated with premature death and a number of serious complications. The presence of comorbid depression makes these outcomes more likely and results in increased healthcare costs. The aim of this work was to assess the health economic outcomes associated with having both diabetes and depression, and assess the cost-effectiveness of potential policy changes to improve the care pathway: improved opportunistic screening for depression, collaborative care for depression treatment, and the combination of both. METHODS: A mathematical model of the care pathways experienced by people diagnosed with type-2 diabetes in England was developed. Both an NHS perspective and wider social benefits were considered. Evidence was taken from the published literature, identified via scoping and targeted searches. RESULTS: Compared with current practice, all three policies reduced both the time spent with depression and the number of diabetes-related complications experienced. The policies were associated with an improvement in quality of life, but with an increase in health care costs. In an incremental analysis, collaborative care dominated improved opportunistic screening. The incremental cost-effectiveness ratio (ICER) for collaborative care compared with current practice was £10,798 per QALY. Compared to collaborative care, the combined policy had an ICER of £68,017 per QALY. CONCLUSIONS: Policies targeted at identifying and treating depression early in patients with diabetes may lead to reductions in diabetes related complications and depression, which in turn increase life expectancy and improve health-related quality of life. Implementing collaborative care was cost-effective based on current national guidance in England.

How do individuals value health states? A qualitative investigation.

Despite the importance of health state values in informing resource allocation in health care, there is arguably little known about how individuals value health. Previous studies have shown that a variety of non-health factors and beliefs are important in valuing health, but there is less evidence in the literature about how individuals' beliefs affect their preferences or what role non-health factors play in the process of forming preferences. This study investigated the thought processes of 21 U.K. based participants in March 2013 who valued health states using semi-structured interviews and a think-aloud protocol, with the aim to better understand the relationship between health states, the individual's underlying beliefs, and the individual's preferences. Participants followed several stages in valuing health. First, participants interpreted the health states more concretely, relying on their imagination and their experience of ill health. Participants judged how the concrete health problems combined with their personal interests, circumstances, and environment would affect them personally. Ultimately, participants valued health by estimating and weighing the non-health consequences of the health states. Six consequences were most frequently mentioned: activities, enjoyment, independence, relationships, dignity, and avoiding being a burden. At each stage participants encountered difficulties and expressed concerns. The findings have implications for methods of describing health, for example, whether the focus should be on health or a broader notion of well-being and capability. This is because the consequences are similar to the domains of broader measures such as the ICECAP measures for adults and older people, and the Warwick-Edinburgh Mental Wellbeing Scale. The findings suggest the need for testing whether individuals are informed about the health states they are valuing. Participants valued health by estimating the non-health consequences of health states and these estimates relied on individuals' beliefs about the interaction of the health state and their personal and social circumstances.

QLU-C10D: a health state classification system for a multi-attribute utility measure based on the EORTC QLQ-C30.

PURPOSE: To derive a health state classification system (HSCS) from the cancer-specific quality of life questionnaire, the EORTC QLQ-C30, as the basis for a multi-attribute utility instrument. METHODS: The conceptual model for the HSCS was based on the established domain structure of the QLQ-C30. Several criteria were considered to select a subset of dimensions and items for the HSCS. Expert opinion and patient input informed a priori selection of key dimensions. Psychometric criteria were assessed via secondary analysis of a pooled dataset comprising HRQOL and clinical data from 2616 patients from eight countries and a range of primary cancer sites, disease stages, and treatments. We used confirmatory factor analysis (CFA) to assess the conceptual model's robustness and generalisability. We assessed item floor effects (>75 % observations at lowest score), disordered item response thresholds, coverage of the latent variable and differential item function using Rasch analysis. We calculated effect sizes for known group comparisons based on disease stage and responsiveness to change. Seventy-nine cancer patients assessed the relative importance of items within dimensions. RESULTS: CFA supported the conceptual model and its generalisability across primary cancer sites. After considering all criteria, 12 items were selected representing 10 dimensions: physical functioning (mobility), role functioning, social functioning, emotional functioning, pain, fatigue, sleep, appetite, nausea, bowel problems. CONCLUSIONS: The HSCS created from QLQ-C30 items is known as the EORTC Quality of Life Utility Measure-Core 10 dimensions (QLU-C10D). The next phase of the QLU-C10D's development involves valuation studies, currently planned or being conducted across the globe.

Using a discrete choice experiment to value the QLU-C10D: feasibility and sensitivity to presentation format.

PURPOSE: To assess the feasibility of using a discrete choice experiment (DCE) to value health states within the QLU-C10D, a utility instrument derived from the QLQ-C30, and to assess clarity, difficulty, and respondent preference between two presentation formats. METHODS: We ran a DCE valuation task in an online panel (N = 430). Respondents answered 16 choice pairs; in half of these, differences between dimensions were highlighted, and in the remainder, common dimensions were described in text and differing attributes were tabulated. To simplify the cognitive task, only four of the QLU-C10D's ten dimensions differed per choice set. We assessed difficulty and clarity of the valuation task with Likert-type scales, and respondents were asked which format they preferred. We analysed the DCE data by format with a conditional logit model and used Chi-squared tests to compare other responses by format. Semi-structured telephone interviews (N = 8) explored respondents' cognitive approaches to the valuation task. RESULTS: Four hundred and forty-nine individuals were recruited, 430 completed at least one choice set, and 422/449 (94 %) completed all 16 choice sets. Interviews revealed that respondents found ten domains difficult but manageable, many adopting simplifying heuristics. Results for clarity and difficulty were identical between formats, but the "highlight" format was preferred by 68 % of respondents. Conditional logit parameter estimates were monotonic within domains, suggesting respondents were able to complete the DCE sensibly, yielding valid results. CONCLUSION: A DCE valuation task in which only four of the QLU-C10D's ten dimensions differed in any choice set is feasible for deriving utility weights for the QLU-C10D.

Patients' knowledge about paracetamol (acetaminophen): a study in a French hospital emergency department.

UNLABELLED: Paracetamol is the most widely used analgesic and antipyretic drug. In France, little is known concerning patients' knowledge and beliefs about paracetamol. OBJECTIVE: To determine how much outpatients attending an emergency department know about paracetamol. METHOD: A semi-structured questionnaire was applied to patients consulting for non-severe medical or traumatic conditions. RESULTS: Thirty-three (45%) of 73 participating patients knew that paracetamol was the active ingredient of the medication they used to reduce pain and/or fever. Three patients thought 2g was the maximum recommended single dose; 25% thought that a delay between two doses ≤ 3 hours was recommended and 15% thought the maximum daily dose was > 4 g. While 8% cited liver toxicity as a side effect, 38% did not believe an excessive dose could be fatal. Two patients correctly answered all questions and five gave no correct answer. DISCUSSION: Outpatients attending an emergency department (ED) have poor knowledge about paracetamol. This situation is disturbing and our results may serve as an eye opener to healthcare professionals. They emphasize the need for research programs with the following objectives: a) to determine the actual content of the message delivered by healthcare professionals; b) to study conditions under which this message is issued; c) to analyze how patients understand key messages and what their behavioral response is. CONCLUSION: In ED patients, the level of knowledge about paracetamol is insufficient to ensure its safe use in ambulatory care. Further studies are needed to determine the causes and to permit better patient education.

Development of DEMQOL-U and DEMQOL-PROXY-U: generation of preference-based indices from DEMQOL and DEMQOL-PROXY for use in economic evaluation.

BACKGROUND: Dementia is one of the most common and serious disorders in later life and the economic and personal cost of caring for people with dementia is immense. There is a need to be able to evaluate interventions in dementia using cost-effectiveness analyses, but the generic preference-based measures typically used to measure effectiveness do not work well in dementia. Existing dementia-specific measures can effectively measure health-related quality of life but in their current form cannot be used directly to inform cost-effectiveness analysis using quality-adjusted life-years as the measure of effectiveness. OBJECTIVES: The aim was to develop two brief health-state classifications, one from DEMQOL and one from DEMQOL-Proxy, to generate health states amenable to valuation. These classification systems consisted of items taken from DEMQOL and DEMQOL-Proxy so they can be derived from any study that has used these instruments. DATA SOURCES: In the first stage of the study we used a large, clinically representative sample aggregated from two sources: a sample of patients and carers attending a memory service in south London and a sample of patients and carers from other community services in south London. This included 644 people with a diagnosis of mild/moderate dementia and 689 carers of those with mild/moderate dementia. For the valuation study, the general population sample of 600 respondents was drawn to be representative of the UK general population. Households were sampled in urban and rural areas in northern England and balanced to the UK population according to geodemographic profiles. In the patient/carer valuation study we interviewed a sample of 71 people with mild dementia and 71 family carers drawn from a memory service in south London. Finally, the instruments derived were applied to data from the HTA-SADD (Study of Antidepressants for Depression in Dementia) trial. REVIEW METHODS: This was a complex multiphase study with four linked phases: phase 1 - derivation of the health-state classification system; phase 2 - general population valuation survey and modelling to produce values for every health state; phase 3 - patient/carer valuation survey; and phase 4 - application of measures to trial data. RESULTS: All four phases were successful and this report details this development process leading to the first condition-specific preference-based measures in dementia, an important new development in this field. LIMITATIONS: The first limitation relates to the lack of an external data set to validate the DEMQOL-U and DEMQOL-Proxy-U classification systems. Throughout the development process we have made decisions about which methodology to use. There are other valid techniques that could be used and it is possible to criticise the choices that we have made. It is also possible that the use of a mild to moderate dementia sample has resulted in classification systems that do not fully reflect the challenges of severe dementia. CONCLUSION: The results presented are sufficiently encouraging to recommend that the DEMQOL instruments be used alongside a generic measure such as the European Quality of Life-5 Dimensions (EQ-5D) in future studies of interventions in dementia as there was evidence that they can be more sensitive for patients at the milder end of disease and some limited evidence that the person with dementia measure may be able to reflect deterioration. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Mapping from disease-specific to generic health-related quality-of-life scales: a common factor model.

OBJECTIVES: To develop a coherent method for estimating mappings between treatment effects on disease-specific measurement (DSM) instruments and generic health-related quality-of-life (QOL) measures, when both are subject to measurement errors. METHODS: We identified three properties that must be satisfied for mappings to be logically coherent: invertability, transitivity, and invariance to linear transformation. Of the common regressions, ordinary least squares (OLS), geometric mean (GM), and orthogonal regression, only GM has all these properties, and then only in special cases. We developed a common factor model of how DSM and generic QOL scales are related, and derived expressions for coherent mapping coefficients. We showed that these are equivalent to adjusted forms of OLS or GM regressions. Where cohort data are available on just one DSM and one QOL measure, external data on the reproducibility of the DSM are required. In some circumstances, the mappings can be estimated without external data. We illustrated the estimation of mapping coefficients by using data on EuroQol five-dimensional (EQ-5D) questionnaire, 12-item short form health survey (SF-12) Mental Component Summary, and the Beck Depression Inventory (BDI), from a trial of treatments for depression. RESULTS: OLS underestimates and GM overestimates mappings from DSMs to generic QOL measures. Mappings estimated by using external data on reliability were similar to those estimated by using internal data, suggesting approximate adequacy of the common factor model. CONCLUSIONS: Neither OLS nor GM regression, unless corrected, is suitable for estimating mappings between disease-specific and generic QOL scales. OLS systematically underestimates mappings, but it can be adjusted by using external information on test-retest reliability.

Estimating quality-adjusted life years from patient-reported visual functioning.

PURPOSE: Glaucoma is an important disease, the impacts of which on vision have been shown to have implications for patients' health-related quality of life (HRQoL). The primary aim of this study is to estimate a mapping algorithm to predict EQ-5D and SF-6D utility values based on the vision-specific measure, the 25-item Visual Functioning Questionnaire (VFQ-25), as well as the clinical measures of visual function, that is, integrated visual field, visual acuity, and contrast sensitivity. METHODS: Ordinary least squares (OLS), Tobit, and censored least absolute deviations were compared using data taken from the Moorfields Eye Hospital in London, to assess mapping functions to predict the EQ-5D and SF-6D from the VFQ-25, and tests of visual function. These models were compared using root mean square error (RMSE), R(2), and mean absolute error (MAE). RESULTS: OLS was the best-performing model of the three compared, as this produced the lowest RMSE and MAE, and the highest R(2). CONCLUSIONS: The models provided initial algorithms to convert the VFQ-25 to the EQ-5D and SF-6D. Further analysis would be needed to validate the models or algorithms.

Developing and testing methods for deriving preference-based measures of health from condition-specific measures (and other patient-based measures of outcome).

OBJECTIVES: Generic preference-based measures such as EQ-5D are widely used to estimate quality-adjusted life-years but may not be available or, more importantly, appropriate in some medical conditions. Condition-specific preference-based measures (CSPBMs) provide an alternative to generic measures that may be more relevant in some conditions. This project conducted five studies to examine issues in the development and use of CSPBMS: (1) literature review of measures; (2) deriving health states values for classifications with highly correlated dimensions; (3) impact of condition labelling; (4) impact of add-on dimensions; and (5) comparative performance of measures. DESIGN: (1) Systematic search and literature review; (2) and (5) psychometric analyses on existing data; (2), (3) and (4) valuation surveys and survey analyses. SETTING: Valuation surveys conducted using face-to-face interviews in the respondents' homes. PARTICIPANTS: Valuation surveys conducted using representative samples of the UK general population. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The project developed a CSPBM CORE-6D and analyses AQL-5D, CORE-6D, EORTC-8D, EQ-5D, OAB-5D and SF-6D data. RESULTS: (1) There was substantial variability in methods used to develop CSPBMs. (2) A new method for generating states using Rasch analysis was undertaken, which successfully dealt with the problem of highly correlated domains. (3) Condition labels affected utility values but this was dependent on the condition and severity of the health state. (4) Adding on an extra dimension affected health-state values and preference weights for other dimensions. (5) The performance of CSPBMs was comparable with that of their parent instrument and of generic preference-based measures with better performance for discrimination between severity groups. CONCLUSIONS: CSPBMs have an important role for economic evaluation, for which generic measures are inappropriate. However, their use in economic evaluation may be compromised by naming the condition; the exclusion of side effects and comorbidities; and focusing effects. Whether a reduction in comparability should be accepted depends on the extent of any gain in validity and responsiveness. This will depend on the condition and measure in question. Research agenda: (1) The appropriateness of generic preference-based measures should be examined in more conditions (and compared with CSPBMs). (2) Further quantitative and qualitative work is requested into the impact of, and reasons for labelling effects. (3) Use of add-ons for condition-specific measures (for side effects and comorbidities) and as a solution to the limitation of generic measures should be explored. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Outcomes of social care for adults: developing a preference-weighted measure.

OBJECTIVE: The aim of this study was to develop a measure of social care outcome, an equivalent to the quality-adjusted life year (QALY) in health, which could be used in a range of circumstances. DESIGN: The project drew on previous and parallel work developing the Adult Social Care Outcome Toolkit and the national Adult Social Care Survey. We developed and tested an instrument designed to reflect service users' social care-related quality of life (SCRQoL) and tested it with 30 service users from a variety of user groups and 300 older home care service users. In parallel, we explored discrete choice experiment (DCE) and best-worst scaling (BWS) approaches to preference elicitation with 300 members of the general population, and cognitively tested these with service users. We also cognitively tested a computer-aided time trade-off (TTO) exercise using SCRQoL attributes with members of the general population. In the second phase, using the finalised instruments, BWS interviews were conducted with 500 members of the general population, TTO interviews with a follow-up sample of 126 of these respondents, and BWS interviews with 458 people using equipment services. MAIN OUTCOME MEASURES: The final measure had eight domains: personal cleanliness and comfort, accommodation cleanliness and comfort, food and drink, safety, social participation and involvement, occupation, control over daily life and dignity. In addition to measuring current SCRQoL, the instrument includes questions used to establish service users' views of their 'expected' SCRQoL in the absence of services. The difference between a person's current and 'expected' SCRQoL provides an indicator of service impact. RESULTS: There was good evidence for the validity of the descriptive system and the validity of the current, expected and SCRQoL gain scales. The DCE and BWS approaches yielded similar results and, once introductions made clear, were understood by service users. BWS was used for the main stages, as it had technical and cognitive advantages. The computer-aided approach to TTO worked well, and respondents found questions acceptable and understandable. There were no substantive differences in the preferences of service users and the general population. The key domain was control over daily life, with the lowest and highest levels strongly estimated in all models. After allowing for observable heterogeneity, service users' preferences appeared to be more closely associated with their own SCRQoL than with those of the general population. The consistency of the results with the results of a previous study allowed the final model to be based on the preferences of 1000 members of the general population. A formula based on the relationship between TTO and BWS values was estimated for a social care QALY, with '0' equivalent to 'being dead' and '1' being the 'ideal' SCRQoL state. Members of the population experienced significantly higher SCRQoL than service users. CONCLUSIONS: Although further work is needed, particularly to develop an equivalent measure for informal carers and to explore the links with health QALYs, the measure has considerable potential. A number of methodological advances were achieved, including the first application of TTO in a social care context and use of BWS to establish service user preferences. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

An evaluation of patient-reported outcome measures in lower limb reconstruction surgery.

PURPOSE: To assess the measurement properties (acceptability, validity, reliability and responsiveness), of the MOS 36-Item Short-Form Health Survey (SF-36), the EQ-5D, the Short-Form McGill Pain Questionnaire (SF-MPQ) and the Musculoskeletal Functional Assessment Instrument (MFA), in patients who have undergone limb reconstruction surgery (LRS). METHODS: Four instruments measuring patient-reported outcome were completed at baseline and 12 months from surgery. RESULTS: 101 LRS patients were recruited with 95 responding at baseline and 71 at a 12-month follow-up. Response rates at baseline were over 94%. In three instruments, there was evidence of floor or ceiling effect, the exception being the EQ-5D. Cronbach's α statistics of internal consistency reliability were acceptable at ≥ 0.80 for all dimensions of the MFA, the SF-MPQ PRI(S) and seven of the SF-36 dimensions. When comparing mean changes in scores between baseline and 12 months, the most responsive measure was the SF-36 with an average Standardised Response Mean of 0.48 for those who reported their health as better. Statistically significant differences were observed between the health change groups ('worse', 'better' and 'same') for four dimensions of the SF-36, the two summary scores and the SF-6D. CONCLUSIONS: Variation and poor performance of some of the instruments resulted in a recommendation of using the SF-36 and the SF-6D for LRS patients.