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, 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 five-factor solutions for DEMQOL and DEMQOL-Proxy. Following item reduction and selection by using Rasch analysis, a five-dimension classification for DEMQOL and a four-dimension classification for DEMQOL-Proxy were developed. Each item contained four 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.

Estimating preference-based single index measures for dementia using DEMQOL and DEMQOL-Proxy.

OBJECTIVE: Although condition-specific measures are commonly used in dementia, they cannot be used in analyses of cost per quality-adjusted life-year because they do not incorporate preferences. We addressed this gap by estimating two preference-based single index measures: the DEMQOL-U from the self-report DEMQOL (mild-to-moderate dementia severity) and the DEMQOL-Proxy-U from the carer-report DEMQOL-Proxy (all levels of dementia severity). METHODS: We conducted valuation studies on 593 members of the general population (306 for the DEMQOL-U, 287 for the DEMQOL-Proxy-U) using the time trade-off elicitation technique. We then fitted a range of mean and individual-level multivariate regression models to the valuation data to derive preference weights for each measure. We applied the estimated weights to a large, clinically representative sample. RESULTS: Mean observed time trade-off values ranged from 0.18 to 0.95 for DEMQOL-U and from 0.33 to 0.96 for DEMQOL-Proxy-U. The best performing models for each measure were main effects models estimated using individual-level data. DEMQOL-Proxy-U had inconsistent but insignificant coefficient estimates for one dimension. Models were estimated to remove these inconsistencies. CONCLUSION: Preference-based single index measures from DEMQOL and DEMQOL-Proxy for use in economic evaluation will enable economic evaluation using quality-adjusted life-years to be undertaken for people across the full range of dementia severity. Future research will examine how the utilities from each measure can be used and combined to populate cost-effectiveness models.

VEINES-QOL/Sym questionnaire was a reliable and valid disease-specific quality of life measure for deep venous thrombosis.

OBJECTIVE: To assess the validity of VEINES-QOL/Sym, a patient-reported questionnaire to evaluate quality of life and symptoms in patients with deep venous thrombosis (DVT). STUDY DESIGN AND SETTING: Psychometric study within the Venous Thrombosis Outcomes (VETO) Study, a prospective cohort study of long-term outcomes after DVT. A total of 359 English- and French-speaking patients with acute, objectively diagnosed DVT were recruited at seven hospitals in Quebec, Canada. The VEINES-QOL/Sym questionnaire, a 26-item patient-reported measure that generates separate summary scores for symptoms (VEINES-Sym) and quality of life (VEINES-QOL) was evaluated for acceptability, reliability, validity, and responsiveness in VETO Study subjects. RESULTS: Standard psychometric tests confirmed the acceptability (missing data, item endorsement frequencies, floor and ceiling effects), reliability (internal consistency, item-total and inter-item correlations, test-retest), validity (content, construct, convergent, discriminant, known groups), and responsiveness to clinical change of the VEINES-QOL/Sym in patients with DVT. CONCLUSION: The VEINES-QOL/Sym is a practical and scientifically sound patient-reported measure of outcomes that was developed using gold-standard methods. VEINES-QOL/Sym is valid and reliable for use as a measure of quality of life and symptoms in patients with acute DVT and provides a rigorous tool to allow more comprehensive evaluation of outcomes in clinical trials and epidemiological studies of patients with DVT.

Costs of dialysis for elderly people in the UK.

BACKGROUND: Growing acceptance rates of elderly patients for dialysis requires a careful planning of renal services expansion. As little is known about the actual resource use in patients 70 years and over, we evaluated the entire range of costs related to treatment, hospitalization, medication and other health and social service use, and assessed the impact of socio-demographic and clinical factors on costs. METHODS: Service use and costs were assessed in a 12-month prospective cohort study of 171 dialysis patients, 70 years of age and over, from four hospital-based renal units in London, UK. RESULTS: Total costs ranged between 14,940 pounds and 58,250 pounds per annum. The average annual cost was 22,740 pounds [95% confidence interval (CI), 21,470-24,020 pounds]. The majority of costs were allocated to dialysis treatment and transport (70%), hospitalizations (12%) and medication (12%). Other health and social services accounted for only 6% of total costs. Dialysis and hospitalization costs were pound 68.4 per day on average. Univariate subgroup analyses showed no significant difference between patients on peritoneal dialysis (64.5 pounds) and haemodialysis (71.5 pounds, P = 0.13). Age 80 years and over and presence of peripheral vascular disease (PVD) were associated with higher daily costs of 73.3 pounds compared with 63.2 pounds in the 70-74 age group (P = 0.033) and 76.9 pounds vs 63.8 pounds in patients without PVD (P = 0.022), respectively. Proximity to death was associated with a nearly pound 40 increase in daily costs (96.8 vs 59.7 pounds; P < 0.001). Multiple linear regression analyses confirmed these findings and showed that age 80 years and over and presence of peripheral and cerebrovascular disease were significant predictors of costs. There was a large but marginally significant difference in costs in patients with cancer. We found no evidence that diabetes was associated with higher dialysis and hospitalization costs. CONCLUSIONS: The costs of providing dialysis for patients 70 years and over are largely shaped by the treatment costs rather than by use of community health and social services. Though age above 80 and co-morbidity are associated with increased resource use, average treatment costs are not higher than estimates for dialysis patients in general. This suggests that there is no case for providing treatment to younger patients and denying it to elderly patients on grounds of cost.

Evaluation of outcomes in community-acquired pneumonia: a guide for patients, physicians, and policy-makers.

Community-acquired pneumonia (CAP) is a key target for research and quality improvement in acute medicine. However, many of the outcome measures used in prognostic and antibiotic studies are not validated and do not capture features of outcome that are important to patients. Substitutes for traditional outcome measures include a recently validated patient-based symptom questionnaire (the CAP-Sym) and process-of-care measures. The interpretation of outcomes also depends on the quality of the study design and methods used. This paper discusses the advantages and disadvantages of outcome, process-of-care, and economic measures in CAP and the interpretation of these measures in randomised and observational studies. A core set of measures for use in clinical CAP research and performance measurement is proposed.

Evaluation of outcomes in chronic venous disorders of the leg: development of a scientifically rigorous, patient-reported measure of symptoms and quality of life.

OBJECTIVE: The purpose of this study was to develop a practical and scientifically rigorous, patient-reported outcome measure to evaluate quality of life and symptoms across the range of conditions (eg, telangiectasias, varicose veins, edema, skin changes, leg ulcers) in chronic venous disorders of the leg (CVDL). METHODS: This study was a psychometric study within the VEnous INsufficiency Epidemiological and Economic Study (VEINES), an international, prospective cohort study to evaluate clinical outcomes, quality of life, costs, and use of health services in CVDL. The study was set in the 166 general practices and 116 specialist clinics in Belgium, France, Italy, and Canada (Quebec) that participated in the VEINES study plus in additional specialist clinics in Ottawa and Montreal. Field testing was carried out in three samples of patients in four countries (Belgium, France, Italy, Canada), including participants in the VEINES study (n dagger 1531) and patients recruited in additional samples of 88 English-speaking patients (Canada) and 53 French-speaking patients (Belgium, France). The reliability and validity sample (n = 615) included 527 VEINES patients and 88 patients from the supplementary English-speaking sample. The test-retest sample (n = 135) included 53 French-speaking and 82 English-speaking patients from the supplementary samples. The responsiveness sample included 1516 VEINES patients. The 26-item VEINES-QOL/Sym is a new, patient-reported questionnaire to evaluate symptoms and quality of life and is available in four language versions (English, French, Italian, French Canadian). RESULTS: Standard psychometric tests confirmed the acceptability (missing data, item endorsement frequencies, floor and ceiling effects), reliability (internal consistency, item-total, inter-item correlations) and validity (content, construct, convergent, discriminant, known groups) of the four language versions of the VEINES-QOL/Sym and the test-retest reliability of the English and French versions and provided preliminary evidence of responsiveness in a pooled language sample. CONCLUSION: The VEINES-QOL/Sym is a practical and scientifically sound, patient-reported measure of outcomes in CVDL that has been developed with rigorous methods. As the only fully validated measure of quality of life and symptoms that is appropriate for use across the full spectrum of CVDL-related conditions, that is quick and easy to administer, and that is available in four languages, the VEINES-QOL/Sym provides a rigorous tool for improving the evaluation of outcomes in clinical trials, epidemiologic studies, and audit.