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Biomedical subjects

G W Torrance

Publications and source records attributed to G W Torrance.

At least 19 recordsLinked to original sources
PubMed1997

Health state utilities in knee replacement surgery: the development and evaluation of McKnee.

OBJECTIVE: 1. To develop McKnee, a classification system and direct utility measure for health states associated with knee replacement (KR) surgery. 2. To apply McKnee in a before-after study of KR surgery to: (i) gain experience with McKnee in an elderly population; (ii) confirm the practicality and usefulness of the McKnee system; (iii) assess self-health utility one week before and 3 mo after surgery; (iv) evaluate the stability of 3 clinical marker health states describing mild, moderate, and severe knee disability; (v) compare self-health utility scores with Short Form 36 (SF-36). METHODS: 1. Instrument development: The McKnee modified Health Utilities Index was developed and used to describe self-health and clinical marker health states: the clinical validity of the clinical marker states was evaluated by 5 clinicians involved in the care off KR patients. 2. Instrument evaluation: McKnee and the SF-36 were administered to 48 patients with osteoarthritis one week before and 3 mo after KR surgery. RESULTS: Before-after study: McKnee was feasible and acceptable in the older patient group studied (mean age in years, SD: 69.9, 8.6). No change in self-health utility (mean, SD) was observed at 3 mo postsurgery: before -0.78, 0.17; after -0.78, 0.21. On the SF-36, only the change scores for pain and health transition were statistically significant. Utilities (mean, SD) for the clinical marker health states were: mild -0.80, 0.20; moderate -0.55, 0.28; and severe -0.48, 0.31. The clinical marker mean utility scores were stable between the baseline and 3 mo assessment, but the intraclass correlation coefficients for individual scores were low. CONCLUSION: McKnee provides a preference based measure of health related quality of life that can be used to obtain and interpret clinically the knee disability utility scorers needed for cost-utility studies and medical decision-making models about KR surgery. The McKnee system provides a practical and useful method for classifying knee disability health states and obtaining direct measurements of utility scores for selected health states.

Aged↗
PubMed1996

Multiattribute utility function for a comprehensive health status classification system. Health Utilities Index Mark 2.

The Health Utilities Index Mark 2 (HUI:2) is a generic multiattribute, preference-based system for assessing health-related quality of life. Health Utilities Index Mark 2 consists of two components: a seven-attribute health status classification system and a scoring formula. The seven attributes are sensation, mobility, emotion, cognition, self-care, pain, and fertility. A random sample of general population parents were interviewed to determine cardinal preferences for the health states in the system. The health states were defined as lasting for a 60-year lifetime, starting at age 10. Values were measured using visual analogue scaling. Utilities were measured using a standard gamble technique. A scoring formula is provided, based on a multiplicative multiattribute utility function from the responses of 194 subjects. The utility scores are death-anchored (death = 0.0) and form an interval scale. Health Utilities Index Mark 2 and its utility scores can be useful to other researchers in a wide variety of settings who wish to document health status and assign preference scores.

Adolescent↗
PubMed1995

Reliability of the Health Utilities Index--Mark III used in the 1991 cycle 6 Canadian General Social Survey Health Questionnaire.

This study presents information on the test-retest reliability of the Health Utility Index--Mark III (HUI) system used in cycle 6 of the Canadian General Social Survey (GSS). The HUI system used in this reliability study consists of an eight-attribute health status classification system (HSCS) and a function for generating a summary score of health-related quality of life. To estimate test-retest reliability, a stratified random sample of individuals (n = 506) completing GSS telephone interviews during August and September, 1991 were interviewed again 1 month later. Weighting adjustments based on the probability of selection were invoked during the analyses to provide unbiased estimates of test-retest reliability for all GSS respondents in the August-September period. The results indicate that the individual questions, attributes and provisional index scores generally provided reliable information on health status in the GSS. The exceptions to this were limitations in speech and dexterity which were reported very infrequently. Kappa estimates of test-retest reliability for individual questions varied from 0.184 to 0.766. For the eight attributes, kappa estimates varied from 0.137 to 0.728. Using the provisional index scores to quantify health overall, a test-retest reliability of 0.767 was obtained (intra-class correlation coefficient).

Activities of Daily Living↗
PubMed1993

The comprehensive assessment of health status in survivors of childhood cancer: application to high-risk acute lymphoblastic leukaemia.

The health status of 69 survivors of high-risk acute lymphoblastic leukaemia (ALL) is assessed using a multi-attribute classification system. Seven attributes are included: sensation, mobility, emotion, cognition, self-care, pain and fertility. Three to five levels of functioning are defined for each attribute. Comprehensive health states are described as a specific combination of seven attribute levels. The system captures combinations of sequelae. The system provides a compact but comprehensive tool for long term follow up of survivors of childhood cancer. The results underscore the cognitive and emotional burdens of morbidity affecting survivors of high-risk ALL.

Cognition Disorders↗
PubMed1993

A study to determine the efficacy and safety of tenoxicam versus piroxicam, diclofenac and indomethacin in patients with osteoarthritis: a meta-analysis.

OBJECTIVE: To obtain a better quantitative and qualitative estimate of the effect of tenoxicam (Tx) compared to piroxicam (Px), diclofenac (Dcl) and indomethacin (Ind) in the treatment of osteoarthritis (OA). METHODS: Relevant studies were identified using computerized Medline search, manual search of cited references and correspondence with investigators, colleagues and the manufacturer of Tx. Once the studies were selected and chosen on the basis of predetermined methodologic criteria, the required data were extracted by 2 authors, independently. Eighteen studies met the required eligibility criteria. Meta-analyses were undertaken on 12 studies of Tx vs Px, 3 studies of Tx vs Dcl, and 2 studies of Tx vs Ind. Efficacy was measured in 2 ways: (1) physician global rating scale and (2) pain scale. Safety was measured in 3 ways: (1) physician global rating scale, (2) number of patients with adverse events, and (3) dropouts due to adverse events. RESULTS: The following findings of the meta-analysis were statistically significant: In Tx vs Px comparisons, efficacy-(1), safety-(1) and safety-(3) were all better with Tx; in Tx vs Ind comparisons, safety-(1) and safety-(2) were better with Tx. All other findings showed no statistically significant differences between Tx and the comparison drug. CONCLUSIONS: Compared to Px, Tx performs better on physician assessment of efficacy and tolerability, but the other comparisons remain inconclusive. Compared to Dcl, there appears not to be a difference. Compared to Ind, Tx is safer.

Aged↗
PubMed1993

An assessment of global health status in survivors of acute lymphoblastic leukemia in childhood.

PURPOSE: Progressive improvement in survival rates of children with cancer demands an appraisal of the "cost of cure." Much information is available on the frequency and severity of individual late effects in long-term survivors, but there are few data on multiple sequelae in individual patients or on global morbidity burdens. PATIENTS AND METHODS: To address this issue, we developed a multiattribute health status classification system. This consists of three to five levels of function within each of seven attributes: sensation, mobility, emotion, cognition, self-care, pain, and fertility. The system was applied to survivors of acute lymphoblastic leukemia (ALL). RESULTS: Overall burdens of morbidity were greater in those who had had "high-risk" disease than in children treated less intensively for "standard-risk" ALL. Deficits in emotional and cognitive status were especially common (alone and in combination). These were more prevalent in younger patients and exhibited a dose relationship to cranial irradiation. CONCLUSIONS: Such appraisals of morbidity must be compared with prevalence rates in the general population.

Activities of Daily Living↗
PubMed1993

Modelling the population health impact of musculoskeletal diseases: arthritis.

OBJECTIVE: A model adjusting for reductions in quality and quantity of life was developed to estimate the population health impact of musculoskeletal diseases. METHODS: Using arthritis as the prototype, prevalence, mortality, and severity data from a variety of sources were combined to model a hypothetical cohort of 1,000 individuals through life. Quality adjusted life years and population health expectancy were calculated for those with arthritis and compared to the general population. RESULTS: Without adjusting for quality of life, a cohort of 1,000 women and 1,000 men at age 15 years could expect 65,010 and 58,735 life years, respectively. Adjusting for quality of life, women with arthritis could expect 61,719 life years, and men 57,123 life years. The unadjusted population health expectancy was 65.0 for girls and 58.7 for boys (at age 15 years). Adjusting for quality of life, the population health expectancies were 61.7 and 57.1, years for women and men, respectively. CONCLUSION: Using this model, the typical adult woman with arthritis can expect to lose 3.3 healthy years of life, and a man, 1.6 healthy years of life. Overall, the model provided a general methodology for determining the population health impact of musculoskeletal diseases. In addition, it is hoped that the methodology will stimulate further research into this area, raise awareness about the uses and limitations of currently available data, and provide a useful model for monitoring the impact of interventions.

Adolescent↗
PubMed1992

A comprehensive multiattribute system for classifying the health status of survivors of childhood cancer.

PURPOSE: A multiattribute health status classification system was devised to describe comprehensively the health status of survivors of childhood cancer. METHODS: The system consists of seven attributes: sensation, mobility, emotion, cognition, self-care, pain, and fertility. Three to five levels of functioning are defined for each attribute. Any specific combination of seven attribute levels constitutes a health state. In the first survey, the system was used to classify the health status of 20 children currently undergoing therapy for high-risk acute lymphoblastic leukemia (ALL), Wilms' tumor, or neuroblastoma, and eight who had completed treatment. A second survey consisted of 13 children with brain tumors on active treatment. RESULTS: In general, independent ratings by clinicians were in agreement, and consensus was readily achieved in 1 to 2 minutes per patient. Children on therapy experienced a higher burden of morbidity than those off treatment. Brain tumor patients experienced more morbidity than patients in the first survey. CONCLUSION: The multiattribute system provides a compact but comprehensive tool for long-term follow-up of survivors of childhood cancer. It captures both multiple sequelae and varying levels of severity. By using a mathematical utility function, a single summary score of health-related quality of life may be assigned to each health state. Additional studies to establish reproducibility, validity, responsiveness, and generalizability are indicated.

Activities of Daily Living↗
PubMed1992

Physical disability among Canadians reporting musculoskeletal diseases.

About one million Canadian adults are estimated to have physical disabilities attributed to a musculoskeletal condition, a prevalence of 50.1/1,000 adults (all rates expressed/1,000). The specific musculoskeletal disease rates were arthritis/rheumatism (27.2), back (16.2), "other" (4.6), trauma (3.6) and bone (0.6). More women reported disabling musculoskeletal disease (61.0 versus 38.6, respectively). Prevalence rates increased with age from 6.2 among Canadians aged 15-24 years, to 264.7 aged 85 years and over. Limitations of mobility were more common than those of agility. Adults in institutions reported more disabilities than did adults in households (means 7.7 and 4.4, respectively).

Adolescent↗
PubMed1989

Controlling health expenditures--the Canadian reality.

Canada and the United States have conducted a large-scale social experiment on the effects of alternative ways of funding expenditures for health care. Two very similar societies, with (until recently) very similar systems of providing health care, have adopted radically different systems of reimbursement. The results of this experiment are of increasing interest to Americans, because the Canadian approach has avoided or solved several of the more intractable problems facing the United States. In particular, overall health expenditures have been constrained to a stable share of national income, and universality of coverage (without user charges) eliminates the problems of uncompensated care, individual burdens of catastrophic illness, and uninsured populations. The combination of cost control with universal, comprehensive coverage has surprised some American observers, who have questioned its reality, its sustainability, or both. We present a comparison of the Canadian and American data on expenditures, identifying the sectors in which the experience of the two nations diverges most, and describing the processes of control. In any system, cost control involves conflict between providers and payers. Political processes focus this conflict, whereas market processes diffuse it. But the stylized political combat in Canada may result in less intrusion on the professional autonomy of the individual physician than is occurring in the United States.

Attitude of Health Personnel↗
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

Incorporating utility-based quality-of-life assessment measures in clinical trials. Two examples.

The utility approach to the measurement of health-related quality of life is discussed and its theoretical foundations and compatibility with economic evaluation are explained. The advantages of the approach include its generalizability, comprehensiveness, ability to integrate mortality and morbidity effects, ability to represent multiple viewpoints, and its incorporation of time and risk preferences in the scores. Disadvantages include interviewer administration, limitations on obtaining scores from all types of subjects, some lack of precision, and attenuated clinical sensibility. Use of the utility approach as an outcome measure in two recent clinical trials is also described. In a trial of an oral gold compound for arthritis, the utility measures were responsive and added information to that from standard clinical and other quality-of-life measures. The utility approach and clinical decision making are being used in an on-going trial of two procedures for prenatal diagnosis in which major potential differences include quality-of-life effects. The comprehensiveness of the utility approach overcomes difficulties in interpreting results from more narrowly focused psychosocial measures of outcome. In sum, the utility model provides a reliable, valid, and responsive approach to measuring quality of life as an outcome in clinical trials.

Adult↗
PubMed1988

Measuring the wellbeing of family caregivers using the time trade-off technique.

In the absence of a quality of life instrument which is applicable to the caregivers of elderly relatives and amenable to a cost-utility analyses, the Caregiver Quality of Life Instrument (CQLI) was developed using Torrance's time trade-off technique. The CQLI was administered to 30 family caregivers and 10 relatives of well elderly. Utility scores were obtained for three standardized caregiver situations and the subject's own state. The CQLI could be completed by almost all subjects. Good test-retest reliability was established. The subjects were able to discriminate between degrees of caregiver wellbeing using standardized states and the CQLI scores discriminated among groups of subjects. The CQLI detected within-subject change in caregivers whose relatives received institutional respite care. The CQLI appears to be feasible, reliable, valid, and responsive to change. Further CQLI applications and research are recommended.

Age Factors↗
PubMed1987

Utility approach to measuring health-related quality of life.

Quality of life is a broad concept that incorporates all aspects of an individual's existence. Health-related quality of life is a subset relating only to the health domain of that existence. The utility approach can be used to measure a single cardinal value, usually between 0 and 1, that reflects the health-related quality of life of the individual at a particular point in time. The utility approach is founded in modern utility theory, a normative rational model of decision-making under uncertainty. The measurement techniques that have been used include standard gamble, time trade-off, and rating scales. The techniques are described in the paper and compared in terms of their acceptability to subjects, reliability, precision, validity, and ease of use. It is concluded that the utility approach is beyond the experimental stage, and is now a viable alternative for investigators to use in measuring health-related quality of life.

Decision Making↗
PubMed1987

Measurement of quality of life in end-stage renal disease: the time trade-off approach.

The quality of life of patients with end-stage renal disease was estimated using the time trade-off technique. The sample included 103 transplant, 60 hospital hemodialysis, 57 home/self-care, and 52 continuous ambulatory peritoneal dialysis patients. Test-retest reliability was high: intra-class correlation coefficient 0.81 (p less than 0.001). The correlations of the time trade-off with the Spitzer Quality of Life index and a visual analogue scale completed by the nephrologists, nurses, friends/relatives, and the patient were positive and statistically significant, but still relatively low (r = 0.22-0.43; p less than 0.01). The time trade-off demonstrated evidence for discriminative construct validity by ordering treatment groups according to a priori prediction. The mean time trade-off values and standard deviations (where death is 0 and full health is 1) were 0.43 (0.26) for hospital hemodialysis 0.49 (0.23) for home/self-care hemodialysis, 0.56 (0.29) for continuous ambulatory peritoneal dialysis, and 0.84 (0.24) for transplant. Analysis of variance showed transplant to be different from all other groups (p less than 0.001) with age, sex, time with end-stage renal disease, and work status making no significant independent contribution. The partial correlation coefficients between time trade-off score and items in the physical, social, and emotional functioning sub-scales of the Rand questionnaire showed that physical functioning was far more important than social or emotional functioning. The time trade-off is reliable, demonstrates evidence for validity, and suggests that the quality of life for patients with end-stage renal disease is much poorer than that reported previously.

Emotions↗
PubMed1984

Developing multiattribute health indexes.

This article reviews the procedures for developing a multiattribute health index for use in population health studies and program evaluations. The development of such indexes involves two steps: 1) the creation of a multiattribute health state classification system; and 2) the mapping of the system into a single metric scale. The system must be relevant for its intended use and as concise as possible. Because a limit exists in the number of attributes that can be included in the system while maintaining reliable measurement, there may be a trade-off between specificity of detail and breadth of coverage. When mapping the system into a scale of cardinal values, five issues arise: 1) the selection of a scaling technique; 2) the use of mathematic models to quantify health; 3) the selection of anchor points; 4) the selection of raters; and 5) the identification of factors that influence raters' judgments. The article reviews the procedures that are used, discusses the issues that arise, and proposes some solutions for the development of multiattribute health indexes.

Classification↗
PubMed1984

Cost-effectiveness of antepartum prevention of Rh immunization.

While antepartum prophylaxis of Rh immunization is much more costly and the postpartum program is much more cost-effective, the question is whether the antepartum program is sufficiently cost-effective to warrant its use. How, in any given region, should the issue be tackled? This article addresses that question.

Antibody Formation↗