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D Feeny

Publications and source records attributed to D Feeny.

70 records · Page 4Linked to original sources
PubMed1989

Utilities and quality-adjusted life years.

Utilities and quality-adjusted life years (QALYs) are reviewed, with particular focus on their use in technology assessment. This article provides a broad overview and perspective on these two techniques and their interrelationship, with reference to other sources for details of implementation. The historical development, assumptions, strengths/weaknesses, and applications of each are summarized. Utilities are specifically designed for individual decision-making under uncertainty, but, with additional assumptions, utilities can be aggregated across individuals to provide a group utility function. QALYs are designed to aggregate in a single summary measure the total health improvement for a group of individuals, capturing improvements from impacts on both quantity of life and quality of life--with quality of life broadly defined. Utilities can be used as the quality-adjustment weights for QALYs; they are particularly appropriate for that purpose, and this combination provides a powerful and highly useful variation on cost-effectiveness analysis known as cost-utility analysis.

Decision Theory↗
PubMed1989

Randomized trials in orthopaedics: why, how, and when?

There is increasing recognition that major new medical therapies should be rigorously evaluated before they are put into general clinical use. Randomized controlled trials provide the most unbiased assessment of the risks and benefits of such therapies. In this article, the most important aspects of the design and execution of a randomized clinical trial in orthopaedics are discussed. These include the reasons for and mechanisms of randomization, appropriate selection of patients and therapy, reasons for the blinding of therapy, types of measures of outcome that can be used, aspects of sample-size calculation and analysis of data, and ethics of randomized controlled trials.

Cementation↗
PubMed1986

Guidelines for the clinical and economic evaluation of health care technologies.

The health care system is routinely confronted with promising new technologies. In the past, most new technologies have been integrated into clinical practice without a rigorous demonstration of their effectiveness or efficiency. In order to provide a more rational approach to the adoption and utilization of health technology a comprehensive set of guidelines for both clinical and economic evaluation is proposed. While conceived of as an ideal that is unlikely to be universally met in practice, it is argued that decision making can be improved by striving towards this goal. The clinical guidelines stress the advantages of subjecting major new technologies to randomized controlled trials and insisting upon a demonstration of patient benefit in the application of diagnostic technologies. The economic guidelines stress comparisons with relevant alternative uses of the resources and the assessment of the impact on the quality of life. While application of the guidelines will produce rigorous and useful evidence, the final decisions concerning the allocation of health care resources must rest fundamentally on social value judgements and not solely, or even primarily, on informed expert opinion.

Clinical Trials as Topic↗
PubMed1980

Evidence for and characterization of a liver cell proliferation factor from blood plasma of partially hepatectomized rats.

A boiled extract acidified to pH 5.5 from the blood plasma of partially hepatectomized rats was treated with neuraminidase and injected i.p. into untreated rats. The DNA-synthesis of the liver cells showed a four-fold increase in comparison with controls. Extracts from the plasma of partially hepatectomized rats without neuraminidase treatment showed no increase in DNA-synthesis. Injections of boiled acid extracts from plasma of normal rats, however, showed no comparable differences before and after neuraminidase treatment. The activity of neuraminidase treated boiled, plasma extract is lost after treatment both with trypsin-chymotrypsin and with beta-galactosidase. Gel chrmoatography of the factor gave a molecular weight of about 38,000 D. The specific activity of the active extract after chromatography was raised by a factor of 300. According to affinity chromatography the factor was shown to be a glycoprotein containing N-Ac-glucosamine. The factor is inert with respect to the proliferation of spleen and kidney, i.e. it is organ specific. According to these results a regulatory system of hepatopoiesis is proposed.

Acetylglucosamine↗
PubMedDate not supplied

Predictors of health-related quality of life with cardiac rehabilitation after acute myocardial infarction.

BACKGROUND: Health-related quality of life (HRQL) instruments provide valid and responsive outcome measures to assess the impact of disease and the response to interventions. However, they have not been applied widely to studies of rehabilitation after myocardial infarction. PURPOSE: To examine the extent to which baseline sociodemographic and clinical characteristics predict baseline and change in generic and specific HRQL. METHODS: A randomized controlled trial of an 8-week cardiac rehabilitation intervention or usual care, with follow-up for 12 months, in 201 patients with acute myocardial infarction (MI). Multiple regression analysis was used to identify predictors of HRQL. RESULTS: Specific HRQL scores and exercise tolerance improved significantly more in rehabilitation patients than usual care patients by the end of the 8-week intervention. All HRQL measures and exercise tolerance in both groups improved significantly during the 12 month follow-up period but the differences between the groups were trivial. A poor baseline HRQL was the predominant predictor of improved generic and specific HRQL. Furthermore, greater improvement in HRQL consistently was associated with lower levels of cardiovascular risks such as absence of a previous MI or coronary artery bypass surgery, absence of angina, less smoking, and higher exercise tolerance. CONCLUSIONS: Improved generic and specific HRQL was associated with poorer baseline HRQL and less baseline cardiovascular risk. This reinforces the importance of addressing health behavior changes as soon as possible after MI and the usefulness of assessing both generic and specific HRQL in evaluating treatment effectiveness.

Electrocardiography, Ambulatory↗
PubMedDate not supplied

Goal attainment in a randomized controlled trial of rehabilitation after myocardial infarction.

PURPOSE: Goal setting is an established strategy in health behavior change programs although its usefulness remains uncertain. The authors investigate the validity of attainment of a patient-identified goal as an outcome measure in cardiac rehabilitation after myocardial infarction. METHODS: On entry into a randomized controlled trial of cardiac rehabilitation after an acute myocardial infarction, patients identified one activity that, if and when attained, would reflect their perception of a successful recovery. Patients reported whether they had attained their goal and the time of goal attainment. This was then related to trial outcomes that included generic and specific health-related quality of life and percent predicted exercise tolerance. RESULTS: Goals identified by 180 of the 201 (89.6%) patients, were attained by 51.5% at 8 weeks and by 86.5% at 12 months. At the end of the 8-week intervention, there was a substantial trend for fewer rehabilitation than usual care patients to have attained their identified goal (P < 0.06), although rehabilitation patients demonstrated greater improvement in specific health-related quality of life and exercise tolerance than usual care patients (P < 0.05). Among patients who identified a recreational physical activity goal (26.7%), significantly fewer (P < 0.007) rehabilitation than usual care patients had attained their goal at the end of the intervention with no differences in improvement in outcomes. CONCLUSIONS: Although improvement in outcomes was greater in rehabilitation patients than usual care patients at 8 weeks, goal attainment, particularly for the recreational physical activity goal, was greater among usual care patients. The validity of self-identified activity goal attainment as a measure of the efficacy of cardiac rehabilitation is unclear and might give misleading results.

Exercise Therapy↗
PubMedDate not supplied

A comparison of HUI2 and HUI3 utility scores in Alzheimer's disease.

PURPOSE: The Health Utilities Index (HUI) is a generic, multiattribute, preference-based health-status classification system. The HUI Mark 3 (HUI3) differs from the earlier HUI2 by modifying attributes and allowing more flexibility for capturing high levels of impairment. The authors compared HUI2 and HUI3 scores of patients with Alzheimer's disease (AD) and caregivers, and contrasted results of a cost-effectiveness analysis of new drugs for AD using the two systems. METHODS: In a cross-sectional study of 679 AD patient/caregiver pairs, stratified by patient's disease stage (questionable/mild/moderate/severe/profound/terminal) and setting (community/assisted living/nursing home), caregivers completed the combined HUI2/HUI3 questionnaire as proxy respondents for patients and for themselves. RESULTS: Mean (SD) global utility scores for patients were lower on the HUI3 (0.22[0.26]) than on the HUI2 (0.53 [0.21]). Patient HUI3 utility scores ranged from 0.47(0.24) for questionable AD to -0.23 (0.08) for terminal AD, compared with a range of 0.73 (0.15) to 0.14 (0.07) for the HUI2. Among the 203 patients in the severe, profound, and terminal stages, 96 (48%) had negative global HUI3 utility scores, while none had a negative HUI2 score. The utility scores for caregivers were similar on the HUI3 (0.87 [0.14]) and HUI2 (0.87 [0.11]). Cost-effectiveness analysis of a new medication to treat AD showed somewhat more favorable results using the HUI3. CONCLUSIONS: The HUI2 and HUI3 discriminate well across AD stages. Compared with the HUI2, the HUI3 yields lower global utility scores for patients with AD, and more scores for states judged worse than dead. The HUI3 may yield substantially different results from the HUI2, particularly for persons who have serious cognitive impairments such as AD.

Aged↗
PubMedDate not supplied

Visual analog scales: do they have a role in the measurement of preferences for health states?

Visual analog scales (VASs) have long been used as a method of measuring preferences for health outcomes. They are easy and inexpensive to implement, can be administered quickly, and lend themselves to self-completion. Over time, however, disturbing questions have emerged concerning the validity of the VAS approach. This article reviews briefly the history, theory, practice, problems, and advantages of VASs; presents some suggestions to improve the validity of VASs; and recommends a limited but useful role for VASs in the process of measuring preferences for health states.

Consumer Behavior↗
PubMedDate not supplied

Can preference scores for discrete states be used to derive preference scores for an entire path of events? An application to prenatal diagnosis.

The authors conducted a study exploring whether preferences for sequences of events can be approximated by preferences for component discrete states. Visual-analog-scale (VAS) and standard-gamble (SG) scores for a subset of the possible sequences of events (path states) and component temporary and chronic outcomes (discrete states) that can follow prenatal diagnostic decisions were elicited from 121 pregnant women facing a choice between chorionic villus sampling and amniocentesis. For individuals, preference scores for path states could not be predicted easily from discrete-state scores. Mean path-state VAS scores, however, were predicted reasonably accurately by multiple regression models (R2 = 0.85 and 0.82 for two different anchoring schemes), with most measured scores lying within the 95% confidence intervals of the derived scores. It is concluded that, for individual patient decision making, preferences for path states should be elicited. When mean preference values for a population are sought, however, it may be reasonable to derive regression weights from a subset of respondents and then to apply those weights to preferences for discrete states elicited from a larger group.

Adult↗