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Biomedical subjects

A M Garber

Publications and source records attributed to A M Garber.

At least 37 records · Page 2Linked to original sources
PubMed1997

Economic foundations of cost-effectiveness analysis.

To address controversies in the applications of cost-effectiveness analysis, we investigate the principles underlying the technique and discuss the implications for the evaluation of medical interventions. Using a standard von Neumann-Morgenstern utility framework, we show how a cost-effectiveness criterion can be derived to guide resource allocation decisions, and how it varies with age, gender, income level, and risk aversion. Although cost-effectiveness analysis can be a useful and powerful tool for resource allocation decisions, a uniform cost-effectiveness criterion that is applied to a heterogeneous population level is unlikely to yield Pareto-optimal resource allocations.

Cost-Benefit Analysis↗
PubMed1997

The effect of assessment method and respondent population on utilities elicited for Gaucher disease.

Measured preferences have been reported to vary with the method of elicitation and respondent population surveyed. We elicited utilities for Gaucher disease using a multimedia implementation of the time trade-off, standard gamble, and a conceptually different, largely untested approach, the risk-risk trade-off, from those who are healthy, those with a chronic illness and those with Gaucher disease. The risk-risk trade-off produced significantly lower utilities than the other two preference assessment methods and had the poorest test-retest reliability. The respondent's self-rated current health state utility was the most important determinant of utility values elicited by the time trade-off and standard gamble for the hypothetical health states. Our results do not support the use of our implementation of the risk-risk trade-off method. In eliciting preferences for hypothetical health states from the general population, the subjective rating of a respondent's own health state should be considered in determining representative population groups.

Adult↗
PubMed1997

Mortality, hospital admissions, and medical costs of end-stage renal disease in the United States and Manitoba, Canada.

OBJECTIVES: National registry data suggest that mortality rates among patients with end-stage renal disease are lower in Canada than in the United States. Casemix and treatment variables, although limited in such instances, do not explain this difference. Using a more complete set of casemix and treatment variables from clinical databases, this study assesses mortality, hospital admission, and the cost of medical care for patients with end-stage renal disease treated in Manitoba, Canada and the United States. METHODS: Mortality rates were compared in patients with end-stage renal disease treated in the Province of Manitoba and a random sample of US patients enrolled in the US Renal Data System Casemix Severity Study. Hospital admission rates and costs of care were compared in Manitoba patients and in patients with end-stage renal disease in a large health care organization in Detroit, Michigan. RESULTS: Levels of serum creatinine, urea, and estimated glomerular filtration rate indicated more severe renal impairment at the outset of treatment in Manitoba than in the United States. Manitoba patients were more than twice as likely to receive kidney transplants as US Renal Data System patients. No patients in Manitoba used reprocessed dialyzers, compared with 57% of US Renal Data System patients. After adjustment for all casemix and treatment variables, the mortality rate was 47% higher in the United States. The hospital admission rate in Detroit was 41% lower than the hospital admission rate in Manitoba, which primarily reflects the doubled rate of transplantation in Manitoba. Adjusted total monthly costs were $503 higher in Detroit than in Manitoba. CONCLUSIONS: The higher mortality rates in the United States cannot be fully explained by adjustments for observable casemix or treatment variables. Further research is needed to identify factors that explain how Manitoba achieves a lower mortality rate while paying less for end-stage renal disease care than the United States.

Diagnosis-Related Groups↗
PubMed1997

Measurement of the validity of utility elicitations performed by computerized interview.

OBJECTIVES: The authors evaluate a measure of the validity of utility elicitations and study the potential effects of invalid elicitations on population utility values. METHODS: The authors used a computerized survey to describe and measure preferences for three common side-effects of anti-psychotic drugs (tardive dyskinesia [TD], akathesia [AKA], pseudo-parkinsonism). The authors compared the validity of elicitations in 41 healthy volunteers to 22 schizophrenic patients. Preferences were measured using visual analog scale (VAS), pair-wise comparison (PWC), and the Standard Gamble (SG) methods. To assess the validity of each groups' responses, the authors compared the consistency of subjects' rank-order of the desirability of states across methods of preferences assessment (CAMPA). RESULTS: All healthy volunteers and 82% of patients completed the computer survey; of these subjects, 97% of healthy volunteers and 70% of patients indicated they thought they understood the task required of them. However, only 78% of healthy subjects and 44% of patients had a consistent rank ordering of preferences among VAS and PWC ratings; only 80% and 61%, respectively, had a consistent rank ordering preferences among SG and PWC ratings. For two of the three health states, inconsistent subjects had statistically higher SG utilities (for TD, 0.94 versus 0.87, and for AKA 0.92 versus 0.86; P < 0.05). CONCLUSIONS: The CAMPA test can identify potentially invalid preference ratings. Potentially invalid preference ratings may bias the "population" utilities for health states.

Adolescent↗
PubMed1997

Willingness-to-pay utility assessment: feasibility of use in normative patient decision support systems.

The authors developed an automated patient interviewing tool to elicit individuals' willingness-to-pay (WTP) utilities under conditions of uncertainty and examined the reliability of this method and its potential usefulness in clinical decision support. We tested this method in 52 healthy volunteers using a computer-based interview that trained subjects in standard gamble (SG) and WTP methods, and elicited preferences for moderate Gaucher disease using WTP and SG. We assessed the validity of the WTP method by calculating the cost-effectiveness threshold implied by subjects' WTP and SG utilities; we also assessed subjects' understanding and comfort with using WTP for decision making by a questionnaire. The WTP method had good test-retest reliability (r = 0.796), and produced a cost-effectiveness ratio and ratings for understanding and clarity that support its validity. Moreover, many subjects felt that WTP was a reasonable (83%) method for therapeutic decision making and expressed comfort (62%) in using the method for their own health care decisions. These results suggest that a probabilistic method for WTP utility assessment is potentially useful for acquiring patient preferences for use in normative decision support systems.

Adult↗
PubMed1996

Evaluating the federal role in financing health-related research.

This paper considers the appropriate role for government in the support of scientific and technological progress in health care; the information the federal government needs to make well-informed decisions about its role; and the ways that federal policy toward research and development should respond to scientific advances, technology trends, and changes in the political and social environment. The principal justification for government support of research rests upon economic characteristics that lead private markets to provide inappropriate levels of research support or to supply inappropriate quantities of the products that result from research. The federal government has two basic tools for dealing with these problems: direct subsidies for research and strengthened property rights that can increase the revenues that companies receive for the products that result from research. In the coming years, the delivery system for health care will continue to undergo dramatic changes, new research opportunities will emerge at a rapid pace, and the pressure to limit discretionary federal spending will intensify. These forces make it increasingly important to improve the measurement of the costs and benefits of research and to recognize the tradeoffs among alternative policies for promoting innovation in health care.

Adrenergic beta-Antagonists↗
PubMed1996

Polymerase chain reaction for the diagnosis of HIV infection in adults. A meta-analysis with recommendations for clinical practice and study design.

PURPOSE: To do a meta-analysis of studies that have evaluated the sensitivity and specificity of polymerase chain reaction (PCR) assay for the diagnosis of human immunodeficiency virus (HIV) infection in adults. Evaluating the performance of PCR is difficult because in certain clinical situations, the sensitivity or specificity of PCR may exceed those of the current reference standard tests (enzyme immunoassay followed by confirmatory Western blot analysis). Therefore, an additional goal was to develop recommendations for 1) the design of future evaluative studies of PCR and 2) the use of PCR in persons with suspected HIV infection. DATA SOURCES: Studies published between 1988 and 1994 that were identified in a search of 17 computer databases, including MEDLINE, and abstracts identified from conference proceedings. STUDY SELECTION: Studies were included if DNA amplification by PCR was done on peripheral blood mononuclear cells from adults. Ninety-six studies met the inclusion criteria. DATA EXTRACTION: Data were extracted independently by two reviewers. Study design was assessed independently by two investigators blinded to study results. RESULTS: Reported sensitivities for PCR range from 10% to 100%, and specificities range from 40% to 100%. A summary receiver-operating characteristic curve based on all 96 studies has a maximum joint sensitivity and specificity (upper left point on the curve, where sensitivity equals specificity) of 97.0% to 98.1%. If the threshold value that defines a positive PCR result is chosen so that sensitivity is higher than 98.1%, specificity will decrease to less than 98.1%. Conversely, if the threshold value that defines a positive PCR result is chosen so that specificity is greater than 98.1%, sensitivity will decrease to less than 98.1%. If sensitivity and specificity are chosen to be equal, the corresponding false-positive rate is 1.9% to 3.0%. At the maximum joint sensitivity and specificity, the positive predictive value of PCR ranges from 34% to 85% as the prevalence of HIV increases from 1.0% to 10%. We identified seven areas in which study design could be modified to 1) reduce susceptibility to bias in estimates of the sensitivity and specificity of PCR and 2) to increase the generalizability of the study results. These modifications will also help to overcome methodologic problems created by the lack of a reference standard test. CONCLUSIONS: The PCR assay is not sufficiently accurate to be used for the diagnosis of HIV infection without confirmation. Use of PCR for the diagnosis of HIV in adults should be limited to situations in which antibody tests are known to be insufficient. Future studies of PCR performance should be sufficiently large and should use adequate reference standard tests and standardized methods for the performance of PCR. Specimens should be evaluated by persons blinded to clinical status and to the results of other diagnostic tests for HIV infection.

Adult↗
PubMed1996

Cholesterol screening in asymptomatic adults, revisited. Part 2.

OBJECTIVE: To assess the role of serum lipid levels as screening tests in adults. DESIGN: Pooled analysis of clinical trials, supplemented by analysis of data from the Framingham Heart Study, to estimate the effect of cholesterol reduction in patient groups stratified by cardiac risk. STUDY SELECTION: Published randomized controlled trials of cholesterol reduction, meta-analyses of such trials, prospective cohort studies of the association between cholesterol levels and morbidity and death related to coronary heart disease, and cost-effectiveness analyses of cholesterol reduction. DATA ANALYSIS: Two-stage logistic regression on cardiac risk factors and outcomes in the Framingham Heart Study. The first stage predicted the risk for death from coronary heart disease using standard risk factors but not cholesterol; the second stage predicted the risk for death from coronary heart disease and all causes as functions of age and cholesterol level, stratified by the risk predicted from the first stage. RESULTS: Randomized clinical trials show that cholesterol reduction confers survival benefits in patients with symptomatic coronary disease. In asymptomatic middle-aged men, who are at lower risk for death from coronary disease, cholesterol reduction prevents coronary disease but has not been shown to prolong life. The risk model based on analysis of the data from the Framingham Heart Study is consistent with the randomized trial data and shows that in the demographic groups excluded from trials, the hypothetical benefits of cholesterol reduction are greatest when the underlying risk for coronary disease is greatest. CONCLUSIONS: Screening with total cholesterol levels is most likely to be useful when done in populations at high short-term risk for dying of coronary heart disease, such as survivors of myocardial infarction and middle-aged men with multiple cardiac risk factors. In these populations, cholesterol reduction appears to be both effective and cost-effective. In other populations, the benefits of reduction are much smaller or are uncertain.

Adult↗
PubMed1996

The cost of VA-sponsored research.

BACKGROUND: Under pressures to reduce health care costs, clinical income is a shrinking source of support for research. Such pressures also threaten research at the medical centers of the Department of Veterans Affairs (VA). VA research is particularly vulnerable because medical care appropriations constitute a large, though unknown, source of support. This study measures the medical care component and the total of VA research funds. METHOD: The incremental costs of VA research were estimated from a survey of 497 clinician investigators and data on payroll, facility costs, and research grants and appropriations. RESULTS: The incremental costs of VA research totaled $541.4 million in the 1992-93 fiscal year. This included $245.6 million in federal appropriations for VA research, $33.1 million in research grants administered by the VA, and $262.8 million in support from other VA appropriations. Research added as much as $219.8 million to VA patient care costs. CONCLUSION: The VA is adopting strategies to increase the internal payoff of its research. The fiscal constraints facing VA and other academic medical centers mean that they will be able to support research with their own funds only when it benefits them directly.

Cost Allocation↗
PubMed1995

Problems with the report of the Expert Panel on blood cholesterol levels in children and adolescents.

An Expert Panel convened by the National Cholesterol Education Program has recommended selective screening and treatment of children for high blood cholesterol levels, based on family history of cardiovascular disease or high blood cholesterol. This recommendation is problematic for several reasons. First, the recommended diets are likely to cause only a slight decrease in low-density lipoprotein cholesterol levels, the projected benefits of which will be offset by a similar decrease in high-density lipoprotein cholesterol levels. Lack of efficacy of the recommended diets could lead to use of more restrictive diets or to cholesterol lowering drugs. Second, even under optimistic assumptions, beneficial effects of cholesterol intervention will be small and delayed for many decades. As a result, childhood cholesterol-lowering efforts will not be cost-effective. Third, the Expert Panel's recommendations do not address important gender differences. Girls have higher average cholesterol levels than boys. They will therefore qualify for more dietary and drug treatment despite their lower age-adjusted risk of heart disease and the lack of association between cholesterol levels and cardiovascular mortality in women. Finally, recent evidence from randomized trials, cohort studies, and animal experiments suggests that cholesterol lowering may have serious adverse effects. This evidence was not discussed in the Expert Panel's report. Given current evidence, any screening and treatment of children for high blood cholesterol levels is, at best, premature.

Adolescent↗
PubMed1994

Can technology assessment control health spending?

Because medical technology is the most important controllable component of health spending growth, the success of strategies for limiting spending growth depends upon their impact on technology dissemination. Technology assessment is fundamental to any strategy for controlling the adoption of medical technologies. Cost-effectiveness analysis holds particular promise as a method for evaluating alternative health care technologies because it explicitly incorporates costs. This paper describes how the widespread adoption of health insurance promoted the dissemination of medical technologies and how technology dissemination fueled spending growth. It then describes approaches to technology assessment and the ways in which technology assessment, in the form of cost-effectiveness analysis, can be applied to help control spending growth.

Cost-Benefit Analysis↗