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J Kupersmith

Publications and source records attributed to J Kupersmith.

99 records · Page 6Linked to original sources
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Cost-effectiveness analysis in heart disease, Part II: Preventive therapies.

Cost-effectiveness analysis of preventive therapies are reviewed in the following categories: lipid lowering, hypertension, smoking cessation, exercise, and anticoagulation. From review of 8 analyses, cost-effectiveness of primary prevention via cholesterol lowering drugs is generally expensive, whereas that of secondary prevention generally is favorable. However, targeting by age, coexisting risk factors, and gender strongly influence results that are also sensitive to drug costs. Treatment of hypertension (5 analyses) is cost-effective in virtually all patient populations and circumstances and for a wide variety of drugs. It is more so with coexisting risk. Issues relating to compliance and drug costs are important. Smoking cessation (4 analyses) is highly cost-effective and worthwhile. However, data on recidivism are incomplete, and cessation may be more difficult to achieve in the general population versus study patients. In one analysis, an exercise program was found to be cost-effective in prevention of coronary heart disease. Anticoagulants have been analyzed in various circumstances. Their cost-effectiveness is favorable for prosthetic valves, although sensitive to imprecision in monitoring. It is also favorable for mitral stenosis in the presence of atrial fibrillation but not normal sinus rhythm. Cost-effectiveness of heparinization for prosthetic valve patients undergoing surgery is rather variable and depends on type of surgery (major versus minor) and type of valve. Many topics in anticoagulant therapy remain to be explored from a cost-effectiveness point of view.

Adult↗
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Cost-effectiveness analysis in heart disease, Part III: Ischemia, congestive heart failure, and arrhythmias.

Cost-effectiveness analyses were reviewed in the following diagnostic and treatment categories: acute myocardial infarction (MI) and diagnostic strategies for coronary artery disease (CAD), coronary artery bypass graft (CABG) surgery, percutaneous transluminal coronary angioplasty (PTCA), congestive heart failure (CHF), and arrhythmias. In the case of acute MI, coronary care units, as presently used, are rather expensive but could be made much more efficient with more effective triage and resource utilization; reperfusion via thrombolysis is cost-effective, as are beta-blockers and angiotensin-converting enzyme (ACE) inhibitors post-MI in appropriate patients. Cost-effectiveness of CAD screening tests depends strongly on the prevalence of disease in the population studied. Cost-effectiveness of CABG surgery depends on targeting; eg, it is highly effective for such conditions as left-main and three-vessel disease but not for lesser disease. PTCA appears to be cost-effective in situations where there is clinical consensus for its use, eg, severe ischemia and one-vessel disease, but requires further analysis based on randomized data; coronary stents also appear to be cost-effective. In preliminary analysis, ACE inhibition for CHF dominates, ie, saves both money and lives. Cardiac transplant appears to be cost-effective but requires further study. For arrhythmias, implantable cardioverter defibrillators are cost-effective, especially the transvenous device, in life-threatening situations; radiofrequency ablation is also cost-effective in patients with Wolff-Parkinson-White syndrome apart from asymptomatic individuals; and pacemakers have not been analyzed except in the case of biofascicular block, where results were variable depending on the situation and preceding tests.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

Electrophysiologic effects of encainide following acute coronary occlusion in dogs.

Encainide, a benzanilide derivative, is a local anesthetic antiarrhythmic drug. To determine its effects on infarcted and normal tissue in situ, we infused encainide (1.0 mg/kg) for 15 min intravenously followed by 0.01 mg/kg/min for an additional 105 min in 8 adult open-chest, pentobarbital-anesthetized, atrially paced dogs after left anterior descending coronary occlusion. We monitored plasma concentration, blood pressure, and surface electrocardiogram (ECG). We determined conduction intervals from the onset of the QRS in the limb lead ECG to the major deflection of bipolar electrograms recorded in the infarcted and normal zones. We found that the blood pressure did not change significantly. Encainide did significantly prolong the atrial stimulus artifact-to-QRS interval and the QRS duration, as previously reported, and also prolonged intraventricular conduction intervals. In the infarcted zone, the drug prolonged conduction in both subendocardium and subepicardium, and prolongation was of somewhat greater magnitude in this zone than in the normal zone. Encainide prolonged the effective refractory period only in the infarcted zone (19 +/- 5 msec at peak; p less than 0.01). The above electrophysiologic effects may explain in part the previously demonstrated antiarrhythmic properties of this drug.

Anilides↗
PubMedDate not supplied

Confidence intervals for cost-effectiveness ratios.

The problem of variability in computed cost-effectiveness ratios (CERs) is usually addressed by performing sensitivity analyses to determine the effects on these ratios of plausible ranges of values of input parameters. However, the sampling variation that exists in these estimated parameters can be utilized to obtain confidence intervals for cost-effectiveness ratios. As cost-effectiveness analysis becomes more widely used, new techniques need to be developed for establishing when a difference in strategies evaluated is meaningful. A first step is to establish the precision of the CER itself. The authors estimate the precision of a CER in the context of a statistical model in which the primary outcome is survival, with cost and effectiveness defined in terms of the underlying survival distribution (S). Effectiveness (alpha) is measured by life expectancy, restricted to a finite time horizon and discounted at a fixed rate r, alpha = integral of e-rtS(t)dt. Cumulative cost (beta) per patient is regarded as resource utilization and incurred randomly over time depending on the survival experience of the patient, beta = integral of e-rtS(t)dC(t), where C(t) is the total potential resources utilized up to time t. Average cost-effectiveness (ACE) of a single strategy is beta/alpha, and when comparing two strategies, the CER is delta beta/delta alpha, the ratio of the incremental cost to the difference in mean survival. Utilizing the sampling distribution of the Kaplan-Meier estimate of S yields standard errors and confidence intervals for ACE and CER. The technique is applied to survival data from 218 previously studied patients to assess 95% confidence intervals for the CER and ACE of the implantable cardioverter defibrillator as compared with electrophysiology-guided therapy.

Confidence Intervals↗