Allocation of subjects in medical experiments.
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Clinical Trials as Topic↗
Biomedical subjects
M C Weinstein
Publications and source records attributed to M C Weinstein.
The role of the intrinsic fibrinolytic system in the prevention of stasis thrombosis in small veins. An electron microscopic study.
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Aminocaproates↗
Recommendations for reporting cost-effectiveness analyses. Panel on Cost-Effectiveness in Health and Medicine.
OBJECTIVE: This article, the third in a 3-part series, describes recommendations for the reporting of cost-effective analyses (CEAs) intended to improve the quality and accessibility of CEA reports. PARTICIPANTS: The Panel on Cost-Effectiveness in Health and Medicine, a nonfederal panel with expertise in CEA, clinical medicine, ethics, and health outcomes measurement, convened by the US Public Health Service. EVIDENCE: The panel reviewed the theoretical foundations of CEA, current practices, alternative methods, published critiques of CEAs, and criticisms of general CEA methods and reporting practices. CONSENSUS PROCESS: The panel developed recommendations through 2 1/2 years of discussions. Comments on preliminary drafts were solicited from federal government methodologists, health agency officials, and academic methodologists. CONCLUSIONS: These recommendations are proposed to enhance the transparency of study methods, assist analysts in providing complete information, and facilitate the presentation of comparable cost-effectiveness results across studies. Adherence to reporting conventions and attention to providing information required to understand and interpret study results will improve the relevance and accessibility of CEAs.
Cost-Benefit Analysis↗
Cost-effectiveness of vitamin therapy to lower plasma homocysteine levels for the prevention of coronary heart disease: effect of grain fortification and beyond.
CONTEXT: A high homocysteine level has been identified as an independent modifiable risk factor for coronary heart disease (CHD) events and death. Since January 1998, the US Food and Drug Administration has required that all enriched grain products contain 140 microg of folic acid per 100 g, a level considered to decrease homocysteine levels. OBJECTIVES: To examine the potential effect of grain fortification with folic acid on CHD events and to estimate the cost-effectiveness of additional vitamin supplementation (folic acid and cyanocobalamin) for CHD prevention. DESIGN AND SETTING: Cost-effectiveness analysis using the Coronary Heart Disease Policy Model, a validated, state-transition model of CHD events in adults aged 35 through 84 years. Data from the third National Health and Nutrition Examination Survey (NHANES III) were used to estimate age- and sex-specific differences in homocysteine levels. INTERVENTION: Hypothetical comparison between a diet that includes enriched grain products projected to increase folic acid intake by 100 microg/d with the same diet without folic acid fortification; and a comparison between vitamin therapy that consists of 1 mg of folic acid and 0.5 mg of cyanocobalamin and the diet that includes grains fortified with folic acid. MAIN OUTCOME MEASURES: Incidence of myocardial infarction and death from CHD, quality-adjusted life-years (QALYs) saved, and medical costs. RESULTS: Grain fortification with folic acid was predicted to decrease CHD events by 8% in women and 13% in men, with comparable reductions in CHD mortality. The model projected that, compared with grain fortification alone, treating all patients with known CHD with folic acid and cyanocobalamin over a 10-year period would result in 310 000 fewer deaths and lower costs. Over the same 10-year period, providing vitamin supplementation in addition to grain fortification to all men aged 45 years or older without known CHD was projected to save more than 300 000 QALYs, to save more than US $2 billion, and to be the preferred strategy. For women without CHD, the preferred vitamin supplementation strategy would be to treat all women older than 55 years, a strategy projected to save more than 140 000 QALYs over 10 years. CONCLUSIONS: Folic acid and cyanocobalamin supplementation may be cost-effective among many population subgroups and could have a major epidemiologic benefit for primary and secondary prevention of CHD if ongoing clinical trials confirm that homocysteine-lowering therapy decreases CHD event rates.
Adult↗
Productivity costs, time costs and health-related quality of life: a response to the Erasmus Group.
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Cost of Illness↗
Cost-effective choice of antimicrobial therapy for serious infections.
The authors evaluated the financial and health implications of treatment choices for three serious classes of infection: hospital-acquired pneumonia, intra-abdominal infection, and sepsis of unknown origin. Data were obtained from a systematic review of clinical literature and published data bases, by written questionnaire from a panel of infectious disease authorities, and from actual costs at a tertiary-care hospital. For pneumonia and sepsis, the third-generation cephalosporin evaluated (ceftizoxime) was found to be less expensive than other regimens, when costs of dose preparation and administration, monitoring, and toxicity were added to drug acquisition costs. The lowest-cost regimen for intra-abdominal infection was metronidazole plus gentamicin. Modest differences in efficacy would easily outweigh differences in toxicity, however, and could justify the use of more expensive regimens (e.g., mezlocillin plus gentamicin for hospital-acquired pneumonia, and cefoxitin plus gentamicin for intra-abdominal infection). If all regimens are assumed to be equally efficacious, then the third-generation cephalosporin was both lowest in cost and, owing to its low toxicity, greatest in net health benefit.
Abdomen↗
Medical management of gallstones: a cost-effectiveness analysis.
OBJECTIVE: Ursodeoxycholic acid (ursodiol) is an oral dissolution agent recently approved by the Food and Drug Administration for treatment of cholelithiasis. The authors conducted a cost-effectiveness analysis comparing ursodiol with elective cholecystectomy and expectant management for men and women of ages 50 and 70 with typical chronic biliary symptoms. DESIGN: Using published literature and national cost data, the authors performed a decision analysis in which the outcome measures were life expectancy, quality-adjusted life expectancy, and expected lifetime treatment cost. PATIENTS: The analysis applies to patients with symptoms of biliary colic, noncalcified gallstones less than 20 mm in diameter, and functioning oral cholecystograms, who are candidates for elective cholecystectomy. Excluded were patients with acute cholecystitis or known or suspected common bile duct stones. RESULTS: Ursodiol is both clinically advantageous and less expensive than surgery for symptomatic men aged 64 or more, and for symptomatic women aged 69 or more. At ages younger than these, the clinical advantage of surgery is small and could be nullified if ursodiol were targeted at patients for whom dissolution is most likely to be effective, based on evidence of stone size and composition. Expected lifetime costs of ursodiol range from $300-400 more than surgery for 50-year-olds to $700-1,000 less than surgery for 70-year-olds. Ursodiol is the preferred choice for patients throughout this age range who are at significantly elevated risk of operative mortality. CONCLUSION: Ursodiol is a clinically advantageous and cost-effective alternative to elective cholecystectomy, especially for older and high-risk patients.
Acute Disease↗
The costs of prevention.
A prevention program is cost-effective if it yields more health benefits than do alternative uses of health care resources. Some prevention programs meet this standard: either they actually save more health care resources than they utilize, or their net costs per healthy year of life gained are lower than those of alternatives such as curative or palliative medicine. Other prevention programs, however, are less cost-effective than are medical treatments for the same disease. One lesson for public policy is that generalizations about the cost-effectiveness of "prevention" are unwise. Another lesson is that prevention programs should not be subjected to a higher standard than other health programs: they should not be expected to save money, but they should be expected to yield improved health at a reasonable price.
Costs and Cost Analysis↗
Modeling for health care and other policy decisions: uses, roles, and validity.
The role of models to support recommendations on the cost-effective use of medical technologies and pharmaceuticals is controversial. At the heart of the controversy is the degree to which experimental or other empirical evidence should be required prior to model use. The controversy stems in part from a misconception that the role of models is to establish truth rather than to guide clinical and policy decisions. In other domains of public policy that involve human life and health, such as environmental protection and defense strategy, models are generally accepted as decision aids, and many models have been formally incorporated into regulatory processes and governmental decision making. We formulate an analytical framework for evaluating the role of models as aids to decision making. Implications for the implementation of Section 114 of the Food and Drug Administration Modernization Act (FDAMA) are derived from this framework.
Chlorofluorocarbons↗
Representing both first- and second-order uncertainties by Monte Carlo simulation for groups of patients.
Actual implementation of probabilistic sensitivity analysis may lead to misleading or improper conclusions when it is applied to groups of patients rather than individual patients. The practice of combining first- and second-order simulations when modeling the outcome for a group of more than one patient yields an erroneous marginal distribution whenever the parameter values are randomly sampled for each patient while the results are presented as simulated means for the group of patients. This practice results in underrepresenting the second-order uncertainty. It may also distort the shape (especially the symmetry or extent of the tails) in the simulated distribution. As a result, it may lead to premature or incorrect conclusions of superiority. It may also result in inappropriate estimates of the value of further research to inform parameter values.
Confidence Intervals↗
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↗
Challenges for cost-effectiveness research.
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Cost-Benefit Analysis↗
Cost-effectiveness of screening strategies for left main coronary artery disease in patients with stable angina.
To define optimal strategies for screening for left main coronary artery disease (LMCAD), the authors evaluated the cost-effectiveness of exercise tolerance testing and cardiac catheterization in patients with mild stable chest pain, such as patients with definite or probable angina in the Coronary Artery Surgery Study registry (prevalence of LMCAD = 9%). Performance characteristics of the exercise test, operative mortality, long-term survival rates, and rates of crossing over to surgical therapy for patients initially managed with medical therapy were derived from pooled literature data; cost estimates were based on local charge data. Strategies using the exercise test to identify candidates for catheterization were associated with longer life expectancies than either the conservative strategy in which patients would be observed or the more aggressive strategy in which all patients would undergo coronary angiography. The most cost-effective option was to screen patients with an exercise test and to perform catheterization in patients with greater than or equal to 2 mm of ST-segment change. Compared with a strategy of catheterization for greater than or equal to 3 mm of ST-segment change only, this strategy increased life expectancy at marginal costs per year of life saved ranging from $11,263 to $18,100 for 40- to 70-year-old patients, respectively, while, compared with a strategy of observation unless symptoms worsened, its incremental cost-effectiveness was $6,510 to $12,428 per year of life saved. Thus, screening patients with stable chest pain syndromes with exercise tests and performing catheterization for patients with greater than or equal to 2 mm of ST-segment change has cost-effectiveness comparable to that of the treatment of moderate diastolic hypertension.
Adult↗
Time-preference studies in the health care context.
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Attitude of Health Personnel↗
Are healthy-years equivalents an improvement over quality-adjusted life years?
The construct of the healthy-years equivalent (HYE) has been proposed as an alternative to the quality-adjusted life year (QALY) on the grounds that it avoids certain restrictive assumptions about preferences and also incorporates attitudes toward risk. The authors review the construct of the QALY, including both the commonly used risk-neutral formulation and the more general formulation that permits risk aversion (or risk preference) with respect to remaining life years. They show that the HYE adds flexibility to the risk-neutral form of the QALY by permitting the rate of tradeoff between life years and quality of life to depend on the life span, albeit at the cost of eliciting numerous additional time-tradeoff assessments. However, the claim that the HYE incorporates attitudes toward risk is incorrect, and the proposed two-stage procedure to measure HYEs is neither necessary nor sufficient to incorporate attitudes toward risk. In fact, the HYE assumes risk neutrality with respect to healthy years of life and, therefore, is less suitable for decisions under uncertainty than is the general (risk-averse) form of the QALY.
Cost of Illness↗
A note on QALYs, time tradeoff, and discounting.
The theoretical model of QALYs is based on risk neutrality with respect to life years or constant proportional risk posture with respect to life years. It is shown that discounting of QALYs is inconsistent with these assumptions. For discounting to be consistent with individual preferences in a QALY model, individuals have to be risk-neutral with respect to discounted life years or exhibit constant proportional risk posture with respect to discounted life years. For the time-tradeoff method to be consistent with these assumptions, the QALY weights have to be derived by dividing the number of discounted life years in full health by the number of discounted life years in the assessed health states.
Age Factors↗
Life expectancy biases in clinical decision modeling.
Clinical decision models often rely upon survival models predicated on disease-specific hazard functions combined with baseline hazard functions obtained from standard life tables. Two biases may arise in such a modeling process. First, life expectancy estimates may be biased even if estimates of survival probabilities are unbiased (misestimation bias). In simulation studies, the authors discovered that the magnitude of misestimation bias is larger as life expectancy increases, sample size decreases, and censoring percentage increases. In the context of a simple decision analysis, they found that imbalances in the sample sizes for the data used to estimate the parameters among different strategies resulted in non-optimal decisions in the long run. The second bias stems from misspecification of the survival model itself (misspecification bias). Using a simple cost-effectiveness model, the authors found that life expectancies and incremental cost-effectiveness ratios differed depending on whether an excess-mortality or a proportional-hazards model was specified. In addition, a predictable pattern was observed for these two survival models when extrapolated to other age and gender groups.
Bias↗
Oregon's Medicaid ranking and cost-effectiveness: is there any relationship?
The authors examine whether Oregon's 1990, 1991, 1992, and 1993 prioritized lists were ranked in a manner consistent with cost-effectiveness. Two sets of cost-effectiveness data are used: data from economic analyses and Oregon's own cost-effectiveness data. Comparing the ranks of Oregon's lists with the ranks of cost-effectiveness estimates from the literature reveals Spearman correlations of -0.08 for the 1990 list, +0.39 for the 1991 list, +0.25 for the 1992 list, and +0.24 for the 1993 list. Comparing Oregon's lists with Oregon's own cost-effectiveness data reveals rank correlations of +0.99 for the 1990 list, +0.06 for the 1991 list, -0.05 for the 1992 list, and -0.03 for the 1993 list. Thus, there appear to be essentially no relationship between the 1990 list and cost-effectiveness estimates from the economic literature and modest positive relationships between the 1991-93 lists and the literature. In addition, there is virtually no relationship between the 1991-93 lists and Oregon's own cost-effectiveness data. Further, the correlations are very different from +1.0, suggesting that other factors are at play. For example, the 1993 list that is currently being implemented was ranked primarily by improvement in five-year survival and human judgment, not cost-effectiveness.
Cost-Benefit Analysis↗