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Biomedical subjects

M C Weinstein

Publications and source records attributed to M C Weinstein.

At least 73 records · Page 4Linked to original sources
PubMed1994

Costs and effectiveness of angiotensin converting enzyme inhibition in patients with congestive heart failure.

BACKGROUND: Chronic heart failure is associated with a poor prognosis and reduced survival rates. The addition of vasodilator drug therapy to conventional therapy for congestive heart failure has resulted in improved survival. METHODS: Adopting a societal viewpoint, we designed a decision analytic model to analyze the costs and effectiveness of three therapies available for the treatment of congestive heart failure: standard therapy (digoxin and diuretic therapy) plus (1) no vasodilator agents, (2) hydralazine hydrochloride-isosorbide dinitrate combination, and (3) enalapril. In addition, we performed sensitivity analyses to determine which model variables were influential in determining incremental cost-effectiveness ratios (cost of drug, cost of hospitalization, efficacy of agents, etc). We used data from three major randomized controlled trials to estimate treatment efficacy, mortality rates, and hospitalization rates. RESULTS: An additional year of life gained by a patient receiving hydralazine-isosorbide combination therapy compared with standard therapy required an additional expense (incremental cost-effectiveness ratio) of $5600. Compared with the hydralazine-isosorbide combination therapy, the incremental cost-effectiveness ratio for enalapril therapy was $9700 per year of life saved. These results were insensitive to wide variations in our baseline assumptions. CONCLUSIONS: The cost per year of life saved by vasodilator therapy is much lower than that of other accepted medical therapies. Although the cost per year of life saved for hydralazine-isosorbide combination therapy is lower than that for enalapril therapy, enalapril therapy saves more lives, and the incremental cost of enalapril therapy is justified by the added benefits.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1994

Responsiveness and calibration of the General Well-Being Adjustment Scale in patients with hypertension.

We examined the discriminant ability and responsiveness of the General Well-Being Adjustment Scale in patients enrolled in a randomized clinical trial of antihypertensive therapy. We also tried to translate the effects of physical symptoms on general well-being. This secondary analysis used demographic, clinical, physical symptom, and general well-being data for 545 white, male hypertensive patients. General well-being was measured by the General Well-Being Adjustment Scale (GWB) collected on 2 occasions over 8 weeks of treatment. Patients with any one of 14 physical symptoms or problems, compared to those without symptoms, had lower GWB scores (p < 0.003 to p < 0.0001). Decreases of 2.83-8.76 points in GWB scores were observed in patients developing physical symptoms over the 8 week study period (p < 0.05 to p < 0.0001). These effects were demonstrated in patients developing cold sensitivity, sexual problems, chest pain, shortness of breath, loss of taste, nausea, hot or cold spells, numbness and tingling, dry mouth, blurred vision, and dizziness. We conclude that the GWB is responsive to clinically meaningful changes in symptoms and may provide a more complete evaluation of the effects of medical treatment. The GWB is a valid and responsive measure of health status outcomes in the evaluation of antihypertensive treatment.

Adult↗
PubMed1994

Evaluating the potential cost-effectiveness of stenting as a treatment for symptomatic single-vessel coronary disease. Use of a decision-analytic model.

BACKGROUND: Coronary stenting appears to provide more predictable immediate results and lower rates of restenosis than conventional balloon angioplasty for selected lesion types, but its hospital costs are significantly higher. This study was designed to evaluate the potential cost-effectiveness of Palmaz-Schatz coronary stenting relative to conventional balloon angioplasty for the treatment of patients with symptomatic, single-vessel coronary disease. METHODS AND RESULTS: We developed a decision-analytic model to predict quality-adjusted life expectancy and lifetime treatment costs for patients with symptomatic, single-vessel coronary disease treated by either Palmaz-Schatz stenting (PSS) or conventional angioplasty (PTCA). Estimates of the probabilities of overall procedural success (PTCA, 97%; PSS, 98%), abrupt closure requiring emergency bypass surgery (PTCA, 1.0%; PSS, 0.6%), and angiographic restenosis (PTCA, 37%; PSS, 20%) were derived from review of the literature published as of September 1993. Procedural costs were based on the true economic (ie, variable) costs of each procedure at Boston's Beth Israel Hospital. On the basis of these data, coronary stenting was estimated to result in a higher quality-adjusted life expectancy than conventional angioplasty but to incur additional costs as well. Compared with conventional angioplasty, stenting had an estimated incremental cost-effectiveness ratio of $23,600 per quality-adjusted life year gained. Although the cost-effectiveness ratio for stenting changed with variations in assumptions about the relative costs and restenosis rates, it remained less than $40,000 per quality-adjusted year of life gained--and thus was similar to many other accepted medical treatments--unless the stent angiographic restenosis rate was > 23%, the angioplasty restenosis rate was < 34%, or the cost of stenting (including vascular complications) exceeded that of conventional angioplasty by more than $3000. The alternative strategy of secondary stenting (initial angioplasty followed by stenting only for symptomatic restenosis) was estimated to be both less effective and less cost-effective than primary stenting over a wide range of plausible assumptions and thus does not appear to be cost-effective when primary stenting is also an option. CONCLUSIONS: Decision-analytic modeling can be used to evaluate the potential cost-effectiveness of new coronary interventions. Our analysis suggests that despite its higher cost, elective coronary stenting may be a reasonably cost-effective treatment for selected patients with single-vessel coronary disease. Primary stenting is unlikely to be cost-effective for lesions with a low probability of restenosis (eg, < 30%) or for patients for whom the cost of stenting is expected to be much higher than usual (eg, because of a high risk of vascular complications). Given the sensitivity of the cost-effectiveness ratios to even modest variations in the relative restenosis rates and cost estimates, future studies will be necessary to determine more precisely the cost-effectiveness of coronary stenting for specific patient and lesion subsets.

Angioplasty, Balloon, Coronary↗
PubMed1994

ROC curve regression analysis: the use of ordinal regression models for diagnostic test assessment.

Diagnostic tests commonly are characterized by their true positive (sensitivity) and true negative (specificity) classification rates, which rely on a single decision threshold to classify a test result as positive. A more complete description of test accuracy is given by the receiver operating characteristic (ROC) curve, a graph of the false positive and true positive rates obtained as the decision threshold is varied. A generalized regression methodology, which uses a class of ordinal regression models to estimate smoothed ROC curves has been described. Data from a multi-institutional study comparing the accuracy of magnetic resonance (MR) imaging with computed tomography (CT) in detecting liver metastases, which are ideally suited for ROC regression analysis, are described. The general regression model is introduced and an estimate for the area under the ROC curve and its standard error using parameters of the ordinal regression model is given. An analysis of the liver data that highlights the utility of the methodology in parsimoniously adjusting comparisons for covariates is presented.

Algorithms↗
PubMed1993

Clinical outcomes and costs of transcatheter as compared with surgical closure of patent ductus arteriosus. The Patient Ductus Arteriosus Closure Comparative Study Group.

BACKGROUND: Transcatheter implantation of the Rashkind PDA occluder is an alternative to conventional surgical closure of isolated patent ductus arteriosus. Neither the clinical outcomes nor the costs of these procedures have been formally compared. METHODS: We performed a retrospective cohort study to evaluate the clinical outcomes within a seven-month period for comparable patients with patent ductus arteriosus who underwent either placement of an occluder or surgical closure. The patients were treated between 1982 and 1987 at 14 major North American centers where patent ductus arteriosus was closed predominantly by a surgical procedure or by the occluder technique. To estimate inpatient and follow-up costs, we multiplied the observed use of resources by 1989 unit costs based on hospital-accounting and physician-reimbursement data. RESULTS: On the basis of cardiac auscultation at follow-up, the initial procedure resulted in closure of the ductus arteriosus in 77.3 percent of 185 patients in whom the occluder was implanted (95 percent confidence interval, 70.6 to 83.1 percent) and 99.8 percent of 446 surgical patients (95 percent confidence interval, 98.8 to 100.0 percent). Second procedures increased the percentage of successful closures to 87.6 percent (95 percent confidence interval, 81.9 to 92.0 percent) and 100.0 percent (95 percent confidence interval, 99.3 to 100.0 percent) for patients in the occluder and surgical groups, respectively. There were no deaths. Major complications occurred in 2.7 percent of the patients in whom the occluder was implanted (95 percent confidence interval, 0.9 to 6.2 percent) and 0.2 percent of the patients who underwent surgery (95 percent confidence interval, 0.0 to 1.2 percent); moderate complications in 16.8 percent (95 percent confidence interval, 11.7 to 22.9 percent) and 15.0 percent (95 percent confidence interval, 11.8 to 18.7 percent), respectively; and minor complications in 11.4 percent (95 percent confidence interval, 7.2 to 16.8 percent) and 24.9 percent (95 percent confidence interval, 20.9 to 29.2 percent). Including the cost of follow-up care, the mean estimated cost per case treated surgically was $8,838 (in 1989 U.S. dollars), as compared with $11,466 per case treated with the occluder technique. Sensitivity analyses based on our data identified no plausible situations in which the costs of surgery and of implantation of the occluder would be equal. CONCLUSIONS: The more effective and less costly surgical procedure was superior to transcatheter placement of the occluder for closure of isolated patent ductus arteriosus. Consequently, our results do not support the wide-spread dissemination of the occluder procedure for the management of this common congenital lesion.

Cardiac Catheterization↗
PubMed1993

Cost-effectiveness of a smoking cessation program after myocardial infarction.

OBJECTIVES: The purpose of this study was to evaluate the cost-effectiveness of a smoking cessation program initiated after acute myocardial infarction. BACKGROUND: The value of allocating health care resources to smoking cessation programs after myocardial infarction has not been compared with the value of other currently accepted interventions. METHODS: A model was developed to examine the cost-effectiveness of a recently reported smoking cessation program after an acute myocardial infarction. The cost was estimated by considering the resources necessary to implement the program, and the effectiveness was expressed as discounted years of life saved. Years of life saved were estimated by modeling life expectancy using a single declining exponential approximation of life expectancy based on data from published reports. RESULTS: The cost-effectiveness of the nurse-managed smoking cessation program was estimated to be $220/year of life saved. In a one-way sensitivity analysis, the cost-effectiveness of the program remained < $20,000/year of life saved if the program decreased the smoking rate by only 3/1,000 smokers (baseline assumption 26/100 smokers), or if the program cost as much as $8,840/smoker (baseline assumption $100). In a two-way sensitivity analysis, even if the cost of the program were as high as $2,000/participant, the cost-effectiveness of the program would be < $10,000/year of life saved so long as the program helped an additional 12 smokers quit for every 100 enrolled. CONCLUSIONS: Over a wide range of estimates of costs and effectiveness, a nurse-managed smoking cessation program after acute myocardial infarction is an extremely cost-effective intervention. This program is more cost-effective than beta-adrenergic antagonist therapy after myocardial infarction.

Analysis of Variance↗
PubMed1993

Cost-effectiveness considerations in the treatment of heterozygous familial hypercholesterolemia with medications.

When used for the primary prevention of coronary heart disease in persons with heterozygous familial hypercholesterolemia (hFH), a hydroxymethylglutaryl coenzyme A (HMG CoA) reductase inhibitor is projected to be effective and to have very favorable cost-effectiveness ratios at low-to-medium doses. For example, 20 mg of lovastatin per day is estimated to save lives and save money in all men ages 35-44 years with hFH and in women ages 35-44 years with hFH and any other risk factor. The estimated incremental cost effectiveness of 40 mg compared with 20 mg of lovastatin for individuals with hFH ages 35-44 years was less than $45,000 per year of life saved in men with > or = 1 other risk factors and women with > or = 2 other risk factors. The estimated incremental cost-effectiveness ratio of 80 mg compared with 40 mg/day was substantially higher ($100,000 or more per year of life saved) even in the highest risk persons. The estimated cost-effectiveness ratios for primary prevention in hFH were reasonably similar to the favorable ratios for secondary prevention in the general population but substantially better than the estimated ratios for primary prevention in other adults with high cholesterol levels. Any national recommendations regarding the use of medications for individuals with hFH must include cost considerations. Our analyses support the use of low-to-moderate doses of high-cost medications for primary prevention in these patients.

Adult↗
PubMed1993

Economics of elective coronary revascularization. Comparison of costs and charges for conventional angioplasty, directional atherectomy, stenting and bypass surgery.

OBJECTIVES: This study was designed to evaluate more closely the true in-hospital costs of elective revascularization by directional coronary atherectomy and intracoronary stenting and to compare these costs with those of the traditional revascularization alternatives (i.e., conventional balloon angioplasty and coronary artery bypass surgery). BACKGROUND: Previous studies have suggested that total hospital charges for directional coronary atherectomy or intracoronary stenting are significantly higher than those for conventional angioplasty. However, hospital charges do not necessarily reflect true economic costs, and their use may provide misleading data with regard to cost-effectiveness. METHODS: We analyzed in-hospital charges from the itemized hospital accounts of 300 patients undergoing elective angioplasty, directional atherectomy, Palmaz-Schatz coronary stenting or bypass surgery between January 1, 1990 and December 31, 1991. Costs were then derived by adjusting itemized patient accounts for department-specific cost/charge ratios. Catheterization laboratory costs were based on actual resource consumption, and daily room costs were adjusted for the intensity of nursing services provided. RESULTS: Length of hospital stay was similar for atherectomy (2.3 +/- 1.5 days) and conventional angioplasty (2.6 +/- 1.7 days) but significantly longer for stenting (5.5 +/- 2.6 days, p < 0.05). Total costs were also significantly higher for coronary stenting ($7,878 +/- $3,270, median $6,699, p < 0.05) than for angioplasty ($5,396 +/- $2,829, median $4,753) or atherectomy ($5,726 +/- $2,716, median $4,986). However, length of stay, resource consumption (laboratory and radiologic testing, drugs, blood products, for example) and total costs for bypass surgery were still greater than for any of the percutaneous interventional procedures. CONCLUSIONS: In contrast to previous studies utilizing only hospital charges, the in-hospital costs of angioplasty and directional coronary atherectomy were similar. Although the cost of coronary stenting was approximately $2,500 higher than that of conventional angioplasty, the magnitude of this difference was smaller than the $6,300 increment previously suggested on the basis of analysis of hospital charges. These findings reflect the inherent discrepancies between cost-based and charge-based methodologies and may have important implications for future studies evaluating the relative cost-effectiveness of newer coronary interventions.

Aged↗
PubMed1992

Cost effectiveness of thrombolytic therapy with streptokinase in elderly patients with suspected acute myocardial infarction.

BACKGROUND: There is a lack of consensus among cardiologists about the potential benefit of thrombolytic therapy for suspected acute myocardial infarction in older patients. To investigate this issue, we constructed a decision-analytic model for patients 75 years of age or older who present with ST-segment elevation within six hours of the onset of symptoms suggesting acute myocardial infarction. METHODS: The variables incorporated in this model were the probability that the patient has an acute myocardial infarction, the probability of in-hospital death among patients with acute myocardial infarction who do not receive thrombolytic therapy, the probability of a fatal or incapacitating complication resulting from thrombolytic therapy, and the expected relative reduction in the risk of death associated with thrombolytic therapy in patients with acute myocardial infarction. Our analyses were based primarily on the use of streptokinase as the thrombolytic agent. RESULTS: Given our base-line assumptions, the probability of dying in the hospital was 21.4 percent if thrombolytic therapy was given and 24.4 percent if it was not given. In one-way sensitivity analyses, thrombolytic therapy decreased the risk of dying if the probability that the patient had an acute myocardial infarction was assumed to be greater than 9 percent, if the probability of dying in the hospital after an acute myocardial infarction without thrombolytic therapy was assumed to be greater than 3 percent, if the rate of fatal or incapacitating complications due to thrombolytic therapy was assumed to be 4 percent or less, or if the relative reduction in the risk of death associated with thrombolytic therapy was assumed to be greater than 1 percent. On the basis of our base-line assumptions, our estimate of the cost effectiveness of streptokinase therapy (the cost per year of life saved) for an 80-year-old patient with suspected acute myocardial infarction was $21,200. For a wide range of assumptions about risks, benefits, and costs, the cost per year of life saved remained less than $55,000. CONCLUSIONS: Within the limitations imposed by the assumptions used in our analysis, thrombolytic therapy with streptokinase was found to be a beneficial and cost-effective treatment for suspected acute myocardial infarction in elderly patients in a wide variety of clinical circumstances.

Age Factors↗
PubMed1992

Cost and health implications of cholesterol lowering.

BACKGROUND: A broad, scientific consensus supports the role of cholesterol as a risk factor for coronary heart disease and agrees that lowering cholesterol levels will reduce coronary heart disease incidence. Cost-effectiveness analysis is a potentially powerful method for measuring the benefits to be achieved by expenditures of health care dollars. METHODS AND RESULTS: The literature related to the effectiveness and cost-effectiveness of cholesterol lowering was reviewed. Application of cost-effectiveness methodology to the question of cholesterol reduction generally supports the use of population-wide educational programs and the aggressive use of cholesterol-lowering therapy for the secondary prevention of subsequent coronary events in persons with preexisting coronary heart disease. For primary prevention, however, therapy with medication has a favorable cost-effectiveness ratio only in identifiable high-risk persons, and the different costs of the various available medications should be taken into account. Therapy with medications, especially for primary prevention, would be more appealing if the price of the available medications were lower. CONCLUSIONS: High priority should be given to research that could validate these cost-effectiveness projections as well as to further studies of the elderly and women, in whom direct data on the precise costs, risks, and benefits of interventions to lower cholesterol remain sparse.

Anticholesteremic Agents↗
PubMed1992

Cost-effectiveness of screening and early treatment of nephropathy in patients with insulin-dependent diabetes mellitus.

Studies have demonstrated that "antihypertensive" treatment with angiotensin-converting enzyme inhibitors (ACEI) may retard the progress of nephropathy in patients with insulin-dependent diabetes mellitus. To obtain an indication of the potential effect of ACEI treatment and as a guide to future research, the effects of screening and early ACEI treatment programs were estimated using cost-effectiveness models. The preliminary analysis suggests that the early treatment of insulin-dependent diabetes mellitus patients with ACEI is likely to be a very cost-effective use of health care resources. The cost-effectiveness ratio for screening and treatment at the stage of microalbuminuria ($7,900 to $16,500 per year of life saved) compares favorably with those of other medical life-saving interventions. Less-aggressive programs (screening followed by treatment at the stage of proteinuria) would improve life expectancy to a lesser extent but could save net health care costs as well as years of life. Although more exact and comprehensive cost-effectiveness analysis must await clinical trials, these illustrative results demonstrate the range of cost-effectiveness that can be expected from these programs and identify data needed for more decisive policy conclusions.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1992

What is the dentist's occupational risk of becoming infected with hepatitis B or the human immunodeficiency virus?

Surveys have shown that dentists are reluctant to treat persons infected with the human immunodeficiency virus (HIV). However, dentists are much more willing to treat patients with infectious hepatitis B virus (HBV). This study shows that the annual cumulative risk of infection from routine treatment of patients whose seropositivity is undisclosed is 57 times greater from HBV than from HIV, and that the risk of dying from HBV infection is 1.7 times greater than the risk of HIV infection, for which mortality is almost certain.

Attitude of Health Personnel↗
PubMed1991

Cost effectiveness of prophylactic intravenous immune globulin in chronic lymphocytic leukemia.

BACKGROUND: A recent randomized controlled trial of intravenous immune globulin in patients with chronic lymphocytic leukemia and hypogammaglobulinemia demonstrated a statistically significant reduction in the rate of bacterial infections among patients who received intravenous immune globulin. We used decision-analysis techniques to determine whether prophylactic intravenous immune globulin is likely to result in an overall clinical benefit to patients who receive this treatment and to examine its cost effectiveness. METHODS: We constructed a model to compare two strategies: treatment with intravenous immune globulin at a dose of 400 mg per kilogram of body weight every three weeks and no immune globulin therapy. Baseline estimates of the efficacy of intravenous immune globulin were derived from the published results of the randomized trial. The costs of treatment, complications, and infections were estimated on the basis of component costs. Health outcomes were measured in terms of gains in quality-adjusted life expectancy. RESULTS: Intravenous immune globulin therapy can result in a loss of quality-adjusted life expectancy when the inconvenience of treatment is taken into account. If the inconvenience of treatment is not considered, therapy results in a gain of 0.8 quality-adjusted days per patient per year of therapy at a cost of $6 million per quality-adjusted life-year gained. CONCLUSIONS: Decision-analysis modeling may be applied to the results of randomized controlled trials to assess the potential clinical and financial effects of adopting the intervention in medical practice. In the case of intravenous immune globulin therapy in patients with chronic lymphocytic leukemia and hypogammaglobulinemia, this type of analysis suggests that treatment might not result in improved quality or length of life and that it is extraordinarily expensive in comparison with other treatments generally accepted as cost effective.

Agammaglobulinemia↗
PubMed1991

Cost-effectiveness of HMG-CoA reductase inhibition for primary and secondary prevention of coronary heart disease.

To determine the cost-effectiveness of HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase inhibitors (such as lovastatin) for the primary and secondary prevention of coronary heart disease, we used the Coronary Heart Disease Policy Model, a computer-stimulated model that estimates the risk factor-specific annual incidence of coronary heart disease and the risk of recurrent coronary events in persons with prevalent coronary heart disease. When used for secondary prevention, 20 mg/d of lovastatin was estimated to save lives and save costs in younger men with cholesterol levels above 250 mg/dL (6.47 mmol/L) and to have a favorable cost-effectiveness ratio regardless of the cholesterol level except in young women with cholesterol levels below 250 mg/dL (6.47 mmol/L). Doses of 40 mg/d of lovastatin had favorable incremental cost-effectiveness ratios in men with cholesterol levels above 250 mg/dL (6.47 mmol/L). By comparison, primary prevention had favorable cost-effectiveness ratios only in selected subgroups based on cholesterol levels and other established risk factors. We conclude that current national recommendations regarding medication for secondary prevention are not as aggressive as our projections would suggest, while recommendations regarding the use of medications for primary prevention should consider the cost of medication as well as the risk factor profile of the individual patient.

Adult↗
PubMed1991

Uncovering psychiatric test information with graphical techniques of Exploratory Data Analysis.

This article illustrates how Exploratory Data Analysis (EDA) can complement conventional statistical methods in evaluating psychiatric tests. Using one recent EDA computer program, we evaluated the ability of repeated psychiatric screening tests (the General Health Questionnaire [GHQ]) to predict medical and psychiatric service use in a Health Maintenance Organization (HMO), the Harvard Community Health Plan (HCHP). Using a stratified random sample of 244 new HCHP enrollees and viewing three-dimensional graphs of their data from multiple perspectives, we found two subpopulations: low GHQ scorers, for whom the tests did not predict service use; and high scorers, for whom they did. Surprisingly, improving scores forecast increased use and chronically high scores predicted diminished use. Using another stratified random sample of 213 new HCHP enrollees, and with scatterplot matrices from another interactive computer program, we found that high and unchanging GHQ scores forecast HMO dropout. We examine possible interpretations--for example, that chronically distressed patients may become immobilized, diminish service use, and ultimately leave the HMO. We also explain how EDA methods may help uncover elusive results in other data (e.g., mental health outcomes).

Adult↗