Applying mixed methods to pretest the Pressure Ulcer Quality of Life (PU-QOL) instrument.

PURPOSE: Pretesting is key in the development of patient-reported outcome (PRO) instruments. We describe a mixed-methods approach based on interviews and Rasch measurement methods in the pretesting of the Pressure Ulcer Quality of Life (PU-QOL) instrument. METHODS: We used cognitive interviews to pretest the PU-QOL in 35 patients with pressure ulcers with the view to identifying problematic items, followed by Rasch analysis to examine response options, appropriateness of the item series and biases due to question ordering (item fit). We then compared findings in an interactive and iterative process to identify potential strengths and weaknesses of PU-QOL items, and guide decision-making about further revisions to items and design/layout. RESULTS: Although cognitive interviews largely supported items, they highlighted problems with layout, response options and comprehension. Findings from the Rasch analysis identified problems with response options through reversed thresholds. CONCLUSIONS: The use of a mixed-methods approach in pretesting the PU-QOL instrument proved beneficial for identifying problems with scale layout, response options and framing/wording of items. Rasch measurement methods are a useful addition to standard qualitative pretesting for evaluating strengths and weaknesses of early stage PRO instruments.

Cost-effectiveness of magnetic resonance-guided focused ultrasound surgery for treatment of uterine fibroids.

OBJECTIVE: To estimate the cost-effectiveness of a treatment strategy for symptomatic uterine fibroids, which starts with Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS) as compared with current practice comprising uterine artery embolisation, myomectomy and hysterectomy. DESIGN: Cost-utility analysis based on a Markov model. SETTING: National Health Service (NHS) Trusts in England and Wales. POPULATION: Women for whom surgical treatment for uterine fibroids is being considered. METHODS: The parameters of the Markov model of the treatment of uterine fibroids are drawn from a series of clinical studies of MRgFUS, and from the clinical effectiveness literature. Health-related quality of life is measured using the 6D. Costs are estimated from the perspective of the NHS. The impact of uncertainty is examined using deterministic and probabilistic sensitivity analysis. MAIN OUTCOME MEASURES: Incremental cost-effectiveness measured by cost per quality-adjusted life-year (QALY) gained. RESULTS: The base-case results imply a cost saving and a small QALY gain per woman as a result of an MRgFUS treatment strategy. The cost per QALY gained is sensitive to cost of MRgFUS relative to other treatments, the age of the woman and the nonperfused volume relative to the total fibroids volume. CONCLUSIONS: A treatment strategy for symptomatic uterine fibroids starting with MRgFUS is likely to be cost-effective.

The Vascular Access Questionnaire: assessing patient-reported views of vascular access.

BACKGROUND: The use of central venous catheters for vascular access in hemodialysis (HD) patients is associated with an increased risk of complications compared to arteriovenous fistulas (AVF). Despite this, catheter use remains high and patient satisfaction may be an important driver of catheter use. METHODS: We developed the Vascular Access Questionnaire (VAQ) to measure patient-reported views of their vascular access. Chronic HD patients at two centers were asked to rate how bothered they were by 17 access-related problems. VAQ symptom scores were compared between patients using catheters and those using fistulas for vascular access. RESULTS: Two hundred and twenty-two patients were eligible for the study. Symptom score was not different between patients using catheters and those using fistulas (p=0.36). However, patients using fistulas were more likely to be at least moderately bothered by pain, bleeding, bruising, swelling, and the appearance of their access than patients using catheters. Elderly patients reported lower symptom scores with catheters than fistulas. CONCLUSIONS: Patients appear to be primarily concerned with the appearance of their access and cannulation-related complications, particularly the elderly. Better education about the risk of adverse events with catheters and the implementation of measures aimed at reducing cannulation-related complications may help to increase fistula rates and improve patient satisfaction with their vascular access.

Measurement of health-related quality of life for people with dementia: development of a new instrument (DEMQOL) and an evaluation of current methodology.

OBJECTIVES: To develop and validate a psychometrically rigorous measure of health-related quality of life (HRQoL) for people with dementia: DEMQOL. DATA SOURCES: Literature review. Expert opinion. Interviews and questionnaires. REVIEW METHODS: Gold standard psychometric techniques were used to develop DEMQOL and DEMQOL-Proxy. A conceptual framework was generated from a review of the literature, qualitative interviews with people with dementia and their carers, expert opinion and team discussion. Items for each component of the conceptual framework were drafted and piloted to produce questionnaires for the person with dementia (DEMQOL) and carer (DEMQOL-Proxy). An extensive two-stage field-testing was then undertaken of both measures in large samples of people with dementia (n = 130) and their carers (n = 126) representing a range of severity and care arrangements. In the first field test, items with poor psychometric performance were eliminated separately for DEMQOL and DEMQOL-Proxy to produce two shorter, more scientifically robust instruments. In the second field test, the item-reduced questionnaires were evaluated along with other validating measures (n = 101 people with dementia, n = 99 carers) to assess acceptability, reliability and validity. RESULTS: Rigorous evaluation in two-stage field testing with 241 people with dementia and 225 carers demonstrated that in psychometric terms: (1) DEMQOL is comparable to the best available dementia-specific HRQoL measures in mild to moderate dementia, but is not appropriate for use in severe dementia [Mini Mental State Examination (MMSE) <10]; and (2) DEMQOL-Proxy is comparable to the best available proxy measure in mild to moderate dementia, and shows promise in severe dementia. In addition, the DEMQOL system has been validated in the UK in a large sample of people with dementia and their carers, and it provides separate measures for self-report and proxy report, which allows outcomes assessment across a wide range of severity in dementia. CONCLUSIONS: The 28-item DEMQOL and 31-item DEMQOL-Proxy provide a method for evaluating HRQoL in dementia. The new measures show comparable psychometric properties to the best available dementia-specific measures, provide both self- and proxy-report versions for people with dementia and their carers, are appropriate for use in mild/moderate dementia (MMSE >/= 10) and are suitable for use in the UK. DEMQOL-Proxy also shows promise in severe dementia. As DEMQOL and DEMQOL-Proxy give different but complementary perspectives on quality of life in dementia, the use of both measures together is recommended. In severe dementia, only DEMQOL-Proxy should be used. Further research with DEMQOL is needed to confirm these findings in an independent sample, evaluate responsiveness, investigate the feasibility of use in specific subgroups and in economic evaluation, and develop population norms. Additional research is needed to address the psychometric challenges of self-report in dementia and validating new dementia-specific HRQoL measures.

The development of the Indian vision function questionnaire: field testing and psychometric evaluation.

OBJECTIVE: To develop and evaluate the acceptability, reliability, validity, and responsiveness of the Indian vision function questionnaire (IND-VFQ). METHODS: Problem statements from previous qualitative studies were reduced to a 45 item interviewer administered questionnaire representing three a priori domains (general functioning, psychosocial impact, and visual symptoms) which was evaluated in patients with cataract (n = 420), glaucoma (n = 120), diabetic retinopathy, or age related macular degeneration (n = 120) and normal controls (n = 120). Standard methods were used for item reduction and to evaluate psychometric properties. RESULTS: Psychometric item reduction produced a 33 item questionnaire. Psychometric evaluation showed that two of the three scales (psychosocial impact and visual symptoms) had good acceptability, and that all three scales showed high internal consistency (alpha >0.80; item-total correlations 0.54-0.86) and test-retest reliability (>0.89). All three scales showed moderate evidence of convergent and discriminant validity. Responsiveness, assessed in cataract patients (n = 120) before and after surgery, was good for all three scales (effect sizes >1). CONCLUSIONS: The IND-VFQ33 is a psychometrically sound measure of vision function addressing a gap in patient defined measures of vision function developed in populations living in low income countries.

Evidence-based measurement: which disability scale for neurologic rehabilitation?

OBJECTIVE: To compare the 10-item Barthel Index (BI), 18-item Functional Independence Measure (FIM), and 30-item Functional Independence Measure + Functional Assessment Measure (FIM+FAM) as measures of disability outcomes for neurologic rehabilitation. METHODS: A total of 149 inpatients from two rehabilitation units in South England specializing in neurologic disorders were studied. Traditional psychometric methods were used to evaluate and compare acceptability (score distributions), reliability (internal consistency, intrarater reproducibility), validity (concurrent, convergent and discriminant construct), and responsiveness (standardized response mean). RESULTS: All three rating scales satisfied recommended criteria for reliable and valid measurement of disability, and are acceptable and responsive in this study sample. The FIM and FIM+FAM total scales are psychometrically similar measures of global disability. The BI, FIM, and FIM+FAM motor scales are psychometrically similar measures of physical disability. The FIM and FIM+FAM cognitive scales are psychometrically similar measures of physical disability. CONCLUSIONS: In the sample studied, the BI, FIM, FIM+FAM have similar measurement properties, when examined using traditional psychometric analyses. Although instruments with more items and item response categories generate more qualitative information about an outcome, they may not improve its measurement. Results highlight the importance of using recognized techniques of scale construction to develop health outcome measures.

The influence of venous thromboembolism on quality of life and severity of chronic venous disease.

BACKGROUND: It is not known whether burden-of-illness differs in chronic venous disease patients with prior venous thromboembolism compared with patients with other forms of chronic venous disease. OBJECTIVE: To compare severity of disease and quality of life in chronic venous disease patients with and without prior venous thromboembolism. PATIENTS AND METHODS: The VEINES Study population is an international cohort of 1531 outpatients with chronic venous disease in Belgium, France, Italy and Canada. Clinical severity of chronic venous disease graded using the seven-category 'CEAP' scale, and quality of life using standardized generic (SF-36) and venous disease-specific (VEINES-QOL/Sym) questionnaires were compared in patients with and without venous thromboembolism. Multivariable analyses with adjustment for known confounders were used to examine associations between venous thromboembolism and quality of life. RESULTS: One hundred and fifty-one (10%) patients had prior venous thromboembolism. These patients had more severe chronic venous disease than those without venous thromboembolism (P <0.0001), including a higher frequency of healed or active ulcers (29% vs. 7%, respectively). Multivariable analyses controlling for age, sex, country, education, body mass index, years of chronic venous disease and comorbid conditions demonstrated that prior venous thromboembolism was an independent predictor of poorer generic quality of life (SF-36 Mental Component Summary score, P=0.047; SF-36 Physical Component Summary score, P=0.012) and venous disease-specific quality of life (VEINES-QOL, P = 0.0002; VEINES-Sym, P=0.009). CONCLUSIONS: Disease severity is worse and quality of life poorer in chronic venous disease patients with prior venous thromboembolism compared with patients with other forms of chronic venous disease. Our findings support the need for further research of interventions to prevent and treat the long-term complications of venous thromboembolism.

The Quebec Back Pain Disability Scale: conceptualization and development.

The Quebec Back Pain Disability Scale is a new measure of functional disability for patients with back pain. Functional disability was operationalized in terms of perceived difficulty associated with simple physical activities. The content of the scale was developed in several stages, including a literature review, two studies seeking the opinions of patients and experts, pilot testing, and a large, longitudinal study of back pain patients. Forty-eight disability items were extensively studied using standard methods such as test-retest reliability, item-total correlations, and factor analysis, as well as modern techniques based on item response theory. Items that were highly effective in discriminating between different levels of disability were selected for the final, reduced scale. The scale has 20 items, representing six empirically derived categories of activities affected by back pain. Measurement properties of this instrument have been previously discussed.

Driving ability after intravenous fentanyl or diazepam. A controlled double-blind study.

Uncomfortable or moderately painful radiologic diagnostic and therapeutic procedures are being performed increasingly on outpatients. If sedation and analgesia are used, patients cannot drive themselves home or return rapidly to normal activities. This study compares the effect of fentanyl (100 micrograms), diazepam (7.5 mg), and placebo on driving ability of young volunteers as measured by the thacometer. Speed and accuracy were impaired at 30 and 120 minutes by both drugs, and by fentanyl more than diazepam. This study design may be suitable for the assessment of whether patients can drive safely after other analgesic drugs.

Effects of two antidepressants on memory performance in depressed outpatients: a double-blind study.

Forty outpatients with primary depression were randomly assigned on a double-blind basis to treatment with amitriptyline (a tricyclic antidepressant) or clovoxamine (a nontricyclic, experimental antidepressant). Memory and depression were assessed during a pretreatment baseline period and at the end of days 4, 7, and 28 of drug treatment. A signal detection recognition memory task and conventional memory measures (including the Benton Visual Retention, Wechsler Logical Memory, and verbal learning tests) were used to assess memory. Although both drugs led to comparable clinical improvement in depression, they affected memory performance differently. The signal detection recognition memory task detected an impairment in memory after chronic amitriptyline administration, as contrasted with an improvement in memory after chronic administration of clovoxamine. The memory impairment in the amitriptyline group and improvement in the clovoxamine group were the result of changes in sensitivity [P(A)]. No changes in response bias (B) were detected. Conventional memory tests failed to detect drug-related differences in memory between the two groups. On the Benton, errors decreased over time within both drug treatment groups, whereas correct reproductions increased within the amitriptyline group only. However, between-group differences on the Benton did not reach significance. Results from the signal detection task suggest an amitriptyline-associated memory impairment. However, this interpretation is tempered by the finding that conventional memory measures failed to detect differences in memory performance between the two groups. We discuss the limitations of traditional memory measures and the utility of a signal detection approach in studies of psychopharmacologic influences on memory.

Improving the evaluation of therapeutic interventions in multiple sclerosis: development of a patient-based measure of outcome.

OBJECTIVES: To develop a patient-based, disease-specific measure of the health impact of multiple sclerosis (MS) for use in clinical trials and clinical practice. DATA SOURCES: People with MS. Members of the MS Society of Great Britain and Northern Ireland. METHODS: Standard psychometric methods were used to develop the Multiple Sclerosis Impact Scale (MSIS-29) in three stages. Stage 1 (item generation): questionnaire items were generated from 30 patient interviews on the impact of MS on their lives, expert opinion and literature review. Stage 2 (item reduction and scale generation): the questionnaire developed in stage 1 was administered by postal survey to 1530 randomly selected members of the MS Society. Standard item reduction techniques were used to develop a rating scale from the pool of questionnaire items. Stage 3 (psychometric evaluation): the questionnaire was evaluated for data quality, scaling assumptions, acceptability, reliability and validity in a separate postal survey of 1250 MS Society members. Responsiveness was evaluated in 55 people admitted to hospital for rehabilitation and intravenous steroid treatment of MS relapses. RESULTS: Stage 1 resulted in a 129-item questionnaire. Stage 2 resulted in a 29-item rating scale measuring the physical and psychological impact of MS. The MSIS-29 satisfied all recommended psychometric criteria for rigorous measurement. Data quality was excellent: missing data were low, item test-retest reliability was high and scale scores could be generated for over 98% of respondents. Item descriptive statistics, item convergent and discriminant validity, and factor analysis supported summing items to produce two summary scores. MSIS-29 physical and psychological scale scores showed good variability, low floor and ceiling effects, good internal consistency and test-retest reliability. Correlations with other measures and confirmation of hypotheses about group differences provided evidence for the validity of the MSIS-29 as a measure of the physical and psychological impact of multiple sclerosis. Effect sizes provided preliminary evidence for responsiveness. CONCLUSIONS: The 29-item MSIS-29 is a rigorous new measure of the physical and psychological impact of MS. All psychometric criteria were satisfied and there is preliminary evidence of responsiveness. The MSIS-29 is particularly appropriate for use in clinical trials to evaluate therapeutic effectiveness from the patient's perspective. Further critical evaluations of the MSIS-29 completed by people with neurologist-confirmed MS in different settings are suggested. Head-to-head comparisons of the psychometric properties of the MSIS-29 and other outcome measures for MS will help to determine the relative advantages of different instruments so that the choice of measures for studies can be evidence based.

Development and validation of a patient based measure of outcome in ocular melanoma.

BACKGROUND: Patients with uveal melanoma can be treated by a number of modalities. As none of the different treatments offer a survival advantage, a key factor in choosing among treatments is their differential impact on patients' quality of life. A short, patient based questionnaire was developed and validated for evaluating outcomes following treatment for uveal melanoma. METHODS: The 21 item measure of outcome in ocular disease (MOOD) assesses the patient's view of outcome in terms of visual function and the impact of treatment. The reliability and validity of the three MOOD scores (total, vision, impact) were evaluated in 176 patients who had been treated for uveal melanoma (75 brachytherapy, 78 proton beam radiotherapy, 23 enucleation). Of these, 165 patients also completed the SF-36. RESULTS: All three MOOD scales met standard criteria for acceptability, reliability, and validity. The proportion of missing data was low, and responses to all items were well distributed across response categories. Internal consistency, assessed by Cronbach's alpha coefficients, exceeded the standard criterion of 0. 70 for all three summary scores. Item total correlations ranged from 0.22 to 0.77 (mean item total correlation 0.58), indicating good homogeneity. Test-retest correlations for all three summary scores exceeded 0.85. Scaling assumptions, assessed by item convergent and discriminant validity correlations, were met for the vision and impact scores. The MOOD showed good content validity, as assessed by review by ophthalmologists and patients. Construct validity was demonstrated by high intercorrelations between the vision and impact scores and the total scale; higher scores for patients who reported being very satisfied compared with those who were not very satisfied and for those who reported persistent red eye compared with those who did not have this complication (known group differences/hypothesis testing); moderate correlations between the MOOD and the SF-36 and visual acuity (convergent validity); and low correlations between the MOOD and age and sex (discriminant validity). CONCLUSIONS: The MOOD is a practical and scientifically sound patient based measure which can be used in research and audit to evaluate outcomes following treatment for uveal melanoma. It takes 5 minutes to complete and meets standard psychometric criteria for reliability and validity.

The Quebec Back Pain Disability Scale. Measurement properties.

STUDY DESIGN: The Quebec Back Pain Disability Scale is a 20-item self-administered instrument designed to assess the level of functional disability in individuals with back pain. The scale was administered as part of a larger questionnaire to a group of 242 back pain patients. Follow-up data were obtained after several days and after 2 to 6 months. OBJECTIVES: The goal of this study was to determine whether the Quebec scale is a reliable, valid, and responsive measure of disability in back pain, and to compare it with other disability scales. SUMMARY OF BACKGROUND DATA: A number of functional disability scales for back pain are being used, but their conceptual validity is uncertain. Unlike most published instruments, the Quebec scale was constructed using a conceptual approach to disability assessment and empirical methods of item development, analysis, and selection. METHODS: The authors calculated test-retest and internal consistency coefficients, evaluated construct validity of the scale, and tested its responsiveness against a global index of change. Direct comparisons with the Roland, Oswestry, and SF-36 scales were carried out. RESULTS: Test-retest reliability was 0.92, and Cronbach's alpha coefficient was 0.96. The scale correlated as expected with other measures of disability, pain, medical history, and utilization variables, work-related variables, and socio-demographic characteristics. Significant changes in disability over time, and differences in change scores between patients that were expected to differ in the direction of change, were found. CONCLUSIONS: The Quebec scale can be recommended as an outcome measure in clinical trials, and for monitoring the progress of individual patients participating in treatment or rehabilitation programs.

Evaluation of the effectiveness of immunization delivery methods.

Scientific evidence documenting the effectiveness of immunization delivery methods was summarized using the generic approach developed by the Community Health Practice Guidelines Working Group. The delivery methods examined were those for the adult and childhood vaccines of influenza, pneumococcal infection, hepatitis B, measles-mumps-rubella and diphtheria-pertussis-tetanus-polio. Based on a critical appraisal of 54 eligible comparative studies, the effects of different interventions were obtained and pooled effects were calculated for delivery methods oriented to the client, the provider and the system. The results indicate those interventions found to be most effective for each vaccine. This review of the scientific evidence of the effectiveness of immunization delivery methods provides a base for policy development and assists in the planning of resource allocation.

Practice survey of immunization in Canada.

A survey was undertaken in September 1991 to document current immunization practice across Canada. Information was obtained during interviews with provincial epidemiologists and key persons involved in immunization programs and recorded on standard data collection forms. Variations in practice are described in five areas: public/private health administration; legislation; monitoring system/coverage rates/surveillance; vaccine management and costs. As changes are being considered to immunization programs, a critical examination of issues such as standardization (in coding, in assessment of waste, in assessment of coverage), surveillance systems and the use of serosurveys would be beneficial.

Immunization delivery methods: practice recommendations.

Immunization has unequivocally contributed to large-scale reductions in mortality and morbidity due to infectious diseases. In general, consensus on the scheduling of immunizations has been achieved at the national or international level by immunization advisory committees. However, immunization delivery methods are varied and numerous. Although specific methods have been proposed, compared and evaluated, the available evidence has not been comprehensively summarized for informed public health action. This paper integrates evidence based on scientific documentation, a Canada-wide practice survey and expert opinion to formulate practice recommendations for immunization delivery methods and to identify areas for further research.

Chronic venous disorders of the leg: epidemiology, outcomes, diagnosis and management. Summary of an evidence-based report of the VEINES task force. Venous Insufficiency Epidemiologic and Economic Studies.

BACKGROUND: To critically review the classification, epidemiology, outcomes, diagnosis and treatment of chronic venous disorders of the leg (CVDL), to issue evidence-based recommendations, and to identify areas requiring further research. METHODS: Articles identified by an extensive literature search were scored by members of an international task force. Only those articles with a moderate or strong rating for internal validity were retained. RESULTS: A scoring system weighing CVDL severity according to the probability of ulcer occurrence is proposed. Epidemiological data on the frequency of CVDL and its risk factors are reviewed. The following items are evaluated: costs associated with treatment; clinical outcomes related to CVDL and its treatment; available generic and disease-specific measures of quality of life; diagnostic procedures used to detect venous reflux; and efficacy of available treatments. CONCLUSIONS: CVDL is an important public health problem, based on its prevalence, cost and impact on quality of life. High-priority areas for research on CVDL are identified.

Measuring health-related quality of life in venous disease: practical and scientific considerations.

An important and often neglected aspect in the evaluation of patient outcomes in venous disease is quality of life. This paper addresses the why, what, and how of measuring health-related quality of life (HRQL) in venous disease by providing an overview of practical and scientific considerations in developing and using measures of HRQL in general. It begins with a brief overview of developments in the field of measuring HRQL and the definition of HRQL. This is followed by a consideration of issues relevant to the assessment of HRQL including generic and disease-specific measures, multiple components of HRQL, different methods of measurement, measuring change, and cultural appropriateness of HRQL measures. In the next section, criteria for evaluating the scientific credibility and practical utility of HRQL measures are outlined, followed by a description of some widely used generic and disease-specific measures of HRQL, including measures of HRQL in chronic venous disorders of the leg (CVDL).

The Patient Outcomes of Surgery-Hand/Arm (POS-Hand/Arm): a new patient-based outcome measure.

The purpose of this study was to develop and validate a new patient-based outcome measure for hand/arm disorders for use in audit, clinical trials and effectiveness studies. There were three stages. First, we carried out interviews with 40 patients with hand/arm disorders to develop and pilot questionnaire content. Second, in a postal survey with 165 pre- and 181 post-surgery patients, we reduced the number of items and identified scales. Third, in a postal survey with 132 pre- and 204 post-surgery patients we evaluated the psychometric properties of the measure. Findings confirmed the acceptability, reliability, validity and responsiveness to clinical change of the questionnaire. The Patient Outcomes of Surgery-Hand/Arm (POS-Hand/Arm) is a new surgical outcome measure that can be used before and after surgery (29 and 33 items, respectively) to evaluate and compare new techniques, surgical teams and units.

[Psychosocial intervention for persons infected with HIV]. / Intervention psychosociale auprès des personnes infectées par le VIH.

We describe a psychosocial intervention program designed to enhance coping with the stress associated with HIV infection. The NUCARE intervention program is based on six components of coping including: cognitive reframing, problem-solving, relaxation, goal setting, social support and use of resources and services. The rationale and development of the intervention is discussed and practical case examples illustrating the benefits of each component are presented.