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Biomedical subjects

Daniel B Mark

Publications and source records attributed to Daniel B Mark.

At least 37 records · Page 2Linked to original sources
PubMed2005

Amiodarone or an implantable cardioverter-defibrillator for congestive heart failure.

BACKGROUND: Sudden death from cardiac causes remains a leading cause of death among patients with congestive heart failure (CHF). Treatment with amiodarone or an implantable cardioverter-defibrillator (ICD) has been proposed to improve the prognosis in such patients. METHODS: We randomly assigned 2521 patients with New York Heart Association (NYHA) class II or III CHF and a left ventricular ejection fraction (LVEF) of 35 percent or less to conventional therapy for CHF plus placebo (847 patients), conventional therapy plus amiodarone (845 patients), or conventional therapy plus a conservatively programmed, shock-only, single-lead ICD (829 patients). Placebo and amiodarone were administered in a double-blind fashion. The primary end point was death from any cause. RESULTS: The median LVEF in patients was 25 percent; 70 percent were in NYHA class II, and 30 percent were in class III CHF. The cause of CHF was ischemic in 52 percent and nonischemic in 48 percent. The median follow-up was 45.5 months. There were 244 deaths (29 percent) in the placebo group, 240 (28 percent) in the amiodarone group, and 182 (22 percent) in the ICD group. As compared with placebo, amiodarone was associated with a similar risk of death (hazard ratio, 1.06; 97.5 percent confidence interval, 0.86 to 1.30; P=0.53) and ICD therapy was associated with a decreased risk of death of 23 percent (0.77; 97.5 percent confidence interval, 0.62 to 0.96; P=0.007) and an absolute decrease in mortality of 7.2 percentage points after five years in the overall population. Results did not vary according to either ischemic or nonischemic causes of CHF, but they did vary according to the NYHA class. CONCLUSIONS: In patients with NYHA class II or III CHF and LVEF of 35 percent or less, amiodarone has no favorable effect on survival, whereas single-lead, shock-only ICD therapy reduces overall mortality by 23 percent.

Aged↗
PubMed2005

Surgeons' economic profiles: can we get the "right" answers?

Hospitals and payers use economic profiling to evaluate physician and surgeon performance. However, there is significant variation in the data sources and analytic methods that are used. We used information from a hospital's cardiac surgery and cost accounting information systems to create surgeon economic profiles. Three scenarios were examined: (1) surgeon modeled as fixed effect with no patient-mix adjustment; (2) surgeon modeled as fixed effect with patient-mix adjustment; (3) and surgeon modeled as random effect with patient-mix adjustment. We included 574 patients undergoing coronary artery bypass surgery at Baptist Medical Center, Oklahoma City, OK between July 1, 1995 and April 30, 1996. We found that profiles reporting unadjusted average surgeon costs may incorrectly identify high- and low-cost outliers. Adjusting for patient-mix differences and treating surgeons as random effects was the preferred approach. These results demonstrate the need for hospitals to reexamine their economic profiling methods.

Aged↗
PubMed2005

Economic analysis of the Assessment of the Safety and Efficacy of a New Thrombolytic Regimen (ASSENT-3) study: costs of reperfusion strategies in acute myocardial infarction.

BACKGROUND: The ASSENT-3 study examined the safety and efficacy of 3 alternative regimens for ST-elevation acute myocardial infarction: full-dose tenecteplase (TNK-tPA) plus enoxaparin; half-dose TNK-tPA plus unfractionated heparin plus abciximab; and full-dose TNK-tPA plus unfractionated heparin. OBJECTIVE: The aim of the study was to examine the resource and economic effects of the 3 regimens in ASSENT-3 using empirically collected data from the trial. METHODS: Cost estimates for each resource use component collected in ASSENT-3 were derived from Medicare reimbursement rates and from detailed billing data collected as part of a previous study. Costs of study drugs were estimated using average wholesale prices. All analyses were by intention to treat. Resource use and medical costs were examined first in the United States alone, and then in the entire cohort. RESULTS: Differences in costs across treatment arms were primarily due to differences in cost of study medication. Irrespective of source of cost weights, the least expensive alternative among the 3 treatment regimens was TNK-tPA and enoxaparin. Although not statistically significant, in 80% of 1000 bootstrap replications, the TNK-tPA enoxaparin arm was associated with 30-day cost savings relative to the unfractionated heparin arm. CONCLUSION: The favorable clinical outcomes demonstrated for enoxaparin arm relative to the unfractionated heparin arm in ASSENT-3 were accompanied by a favorable distribution of costs and support the designation of this regimen as economically attractive by conventional benchmarks.

Abciximab↗
PubMed2005

Conducting economic evaluations alongside multinational clinical trials: toward a research consensus.

Demand for economic evaluations in multinational clinical trials is increasing, but there is little consensus about how such studies should be conducted and reported. At a workshop in Durham, North Carolina, we sought to identify areas of agreement about how the primary findings of economic evaluations in multinational clinical trials should be generated and presented. In this paper, we propose a framework for classifying multinational economic evaluations according to (a) the sources of an analyst's estimates of resource use and clinical effectiveness and (b) the analyst's method of estimating costs. We review existing studies in the cardiology literature in the context of the proposed framework. We then describe important methodological and practical considerations in conducting multinational economic evaluations and summarize the advantages and disadvantages of each approach. Finally, we describe opportunities for future research. Delineation of the various approaches to multinational economic evaluation may assist researchers, peer reviewers, journal editors, and decision makers in evaluating the strengths and limitations of particular studies.

Clinical Trials as Topic↗
PubMed2005

Implantable cardioverter defibrillators and cardiac resynchronization therapy in patients with left ventricular dysfunction: randomized trial evidence through 2004.

Although many studies have shown that implantable cardioverter defibrillator (ICD) therapy improves the survival of patients with significant left ventricular dysfunction, the magnitude of effectiveness of ICD therapy in clinically defined subgroups remains uncertain. Similarly, although studies have shown an improvement in patients' hemodynamics and quality of life with cardiac resynchronization therapy (CRT), there is a continuing uncertainty about the effect of CRT on patients' survival and the magnitude of improvement in quality of life with this therapy. On August 24, 2004, an ad hoc group of experts representing clinical cardiovascular medicine, biostatistics, economics, and health policy were joined by representatives of the Food and Drug Administration, Centers for Medicare and Medicaid Services (Baltimore, Md), Agency for Healthcare Research and Quality (Rockville, Md), and the device industry for a 1-day round table to review the available clinical trial evidence on the effect of ICD therapy in the primary prevention of sudden cardiac death and the effect of CRT in patients with congestive heart failure. The meeting was organized by the Duke Clinical Research Institute, Durham, NC, and funded in part by the Agency for Healthcare Research and Quality. This document summarizes the evidence reviewed at that meeting and the discussions of that evidence.

Death, Sudden, Cardiac↗
PubMed2005

Design and methodology of the Occluded Artery Trial (OAT).

Experimental and clinical studies have suggested that late opening of an infarct-related artery (IRA) after myocardial infarction (MI) could improve clinical outcome. However, the suggestive observational data are limited by selection biases. Indeed, most small randomized studies have not demonstrated benefit. Thus, there is no recommendation for routine late opening of the IRA in current national guidelines for management of stable post-MI patients. The OAT is designed to test the hypothesis that opening a totally occluded IRA 3 to 28 days after MI in high-risk asymptomatic patients will improve clinical outcome and be cost-effective. The primary end point is the first occurrence of recurrent MI, hospitalization/treatment of New York Heart Association class IV congestive heart failure, or death. Trial background, design, and preliminary baseline characteristics of 2027 randomized patients are presented. Eligible patients are randomly assigned in equal proportions to optimal evidence-based medical care or optimal care plus late opening of the IRA using percutaneous coronary intervention of the occluded IRA. Treatment groups will be compared using intent-to-treat analysis. The results of OAT should have broad clinical impact by defining an evidence-based approach to the asymptomatic, high-risk, post-MI patient with an occluded IRA. If the efficacy and cost-effectiveness of percutaneous coronary intervention are established, then a policy of routinely seeking and opening persistently occluded IRAs could be advocated. If not, this strategy should be avoided in this large subgroup of post-MI patients.

Adult↗
PubMed2004

Medical costs and quality of life 10 to 12 years after randomization to angioplasty or bypass surgery for multivessel coronary artery disease.

BACKGROUND: Coronary bypass surgery (CABG) and angioplasty (PTCA) have been compared in several randomized trials, but data about long-term economic and quality-of-life outcomes are limited. METHODS AND RESULTS: Cost and quality-of-life data were collected prospectively from 934 patients who were randomized in the Bypass Angioplasty Revascularization Investigation (BARI) and followed up for 10 to 12 years. CABG had 53% higher costs initially, but the gap closed to <5% during the first 2 years; after 12 years, the mean cumulative cost of CABG patients was 123,000 dollars versus 120,750 dollars for PTCA, yielding a cost-effectiveness ratio of 14,300 dollars/life-year added. CABG patients experienced significantly greater improvement in their physical functioning for the first 3 years but not in later follow-up. Recurrent angina substantially reduced all quality-of-life measures throughout follow-up. Cumulative costs were significantly higher among patients with diabetes, heart failure, and comorbid conditions and among women; costs also were increased by angina, by the number of revascularization procedures, and among patients who died. CONCLUSIONS: Early differences between CABG and PTCA in costs and quality of life were no longer significant at 10 to 12 years of follow-up. CABG was cost-effective as compared with PTCA for multivessel disease.

Aged↗
PubMed2004

Long-term mortality of patients with acute myocardial infarction in the United States and Canada: comparison of patients enrolled in Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO)-I.

BACKGROUND: In a previous substudy of the GUSTO-I trial, we observed better functional and quality-of-life outcomes among patients in the United States (US patients) compared with patients in Canada. Rates of invasive therapy were significantly higher in the United States and were associated with a small mortality benefit (0.4%, adjusted P=0.02). We sought to determine whether Canadian-US differences in practice patterns in GUSTO-I had an impact on 5-year mortality. METHODS AND RESULTS: Mortality data for 23,105 US and 2898 Canadian patients enrolled in GUSTO-I were obtained from national mortality databases. Median follow-up was 5.46 years in the US and 5.33 years in the Canadian cohort. Five-year mortality rate was 19.6% among US and 21.4% among Canadian patients (P=0.02). After baseline adjustment, enrollment in Canada was associated with a higher hazard of death (1.17; 95% confidence interval, 1.07 to 1.28, P=0.001). Revascularization rates during the index hospitalization in the United States were almost 3 times those in Canada: 30.5% versus 11.4% for angioplasty and 13.1% versus 4.0% for bypass surgery (P<0.01 for both). After accounting for revascularization status as a time-dependent covariate, country was no longer a significant predictor of long-term mortality. These results were confirmed in a propensity-matched analysis. CONCLUSIONS: Our results suggest, for the first time, that the more conservative pattern of care with regard to early revascularization in Canada for ST-segment elevation acute myocardial infarction may have a detrimental effect on long-term survival. Our results have important policy implications for cardiac care in countries and healthcare systems wherein use of invasive procedures is similarly conservative.

Aged↗
PubMed2004

The prognostic importance of comorbidity for mortality in patients with stable coronary artery disease.

OBJECTIVES: To identify the prevalent and prognostically important coexisting illnesses among single coronary artery disease (CAD) patients. BACKGROUND: As the population ages, physicians are increasingly required to make decisions concerning patients with multiple co-existing illnesses (comorbidity). Many trials of CAD therapy have excluded patients with significant comorbidity, such that there are limited data to guide the management of those patients. METHODS: To consider the long-term prognostic importance of comorbid illness, we examined a cohort of 1471 patients with CAD who underwent cardiac catheterization between 1985 and 1989 and were followed up through 2000 in the Duke Databank for Cardiovascular Diseases. Weights were assigned to individual diseases according to their prognostic significance in Cox proportional hazards models, thus creating a new CAD-specific index. The new index was compared with the widely used Charlson index, according to prevalence of conditions, individual and overall associations with survival, and agreement. RESULTS: The Charlson index and the CAD-specific index were highly associated with long-term survival and almost equivalent to left ventricular ejection fraction. When considering the components of the Charlson index, diabetes, renal insufficiency, chronic obstructive pulmonary disease, and peripheral vascular disease had greater prognostic significance among CAD patients, whereas peptic ulcer disease, connective tissue disease, and lymphoma were less significant. Hemiplegia, leukemia, lymphoma, severe liver disease, and acquired immunodeficiency syndrome were rarely identified among patients undergoing coronary angiography. CONCLUSIONS: Comorbid disease is strongly associated with long-term survival in patients with CAD. These data suggest co-existing illnesses should be measured and considered in clinical trials, disease registries, quality comparisons, and counseling of individual patients.

Black People↗
PubMed2004

International differences in evolution of early discharge after acute myocardial infarction.

BACKGROUND: Early discharge of low-risk patients with acute myocardial infarction is feasible and can be achieved at no additional risk of adverse events. We aimed to identify the extent to which countries have taken advantage of the opportunity for early discharge. METHODS: The study population consisted of 54174 patients enrolled in GUSTO-I, GUSTO-III, and ASSENT-2 studies (enrollment period 1990-98) in the USA, Canada, Australia, New Zealand, Belgium, France, Germany, Spain, and Poland. We identified patients with uncomplicated acute myocardial infarction who were eligible for early discharge on the basis of previously established criteria, and assessed the extent to which these patients were discharged early--defined as discharged alive within 4 days of admission. The economic consequences (defined as potentially unnecessary hospital days consumed per 100 patients enrolled) were also investigated. FINDINGS: Patients in all European countries had significantly longer stays than did those from non-European countries. Over the study period, the number of eligible patients discharged on or before day 4 increased in the USA, Canada, Australia, and New Zealand. Despite this increase, no more than 40% of patients who were eligible for early discharge were actually discharged early. The rate of early discharge of eligible patients was consistently low (<2%) in Belgium, France, Germany, Spain, and Poland. In ASSENT-2, which is the most recent trial in this study, the number of potentially unnecessary hospital days (per 100 patients enrolled) ranged from 65 in New Zealand to 839 in Germany. INTERPRETATION: Despite more than a decade of research, there is still a lot of variation between countries in international length-of-stay patterns in acute myocardial infarction. The potential for more efficient discharge of low-risk patients exists in all countries investigated, but was especially evident in the European countries included in the study (Belgium, France, Germany, Spain, and Poland).

Acute Disease↗
PubMed2004

Exploring options for improving healthcare.

New medical technologies generally must receive clearance or approval for marketing by the US Food and Drug Administration and be covered by an insurer, such as the Centers for Medicare and Medicaid Services, before becoming available for widespread clinical use. These 2 approval processes are discrete and usually occur sequentially rather than collaboratively and simultaneously. To explore potential mechanisms for increasing regulatory collaboration between these 2 key health care agencies, the Duke Clinical Research Institute and Health Strategies Consultancy convened an informal meeting of agency, academic, and industry leaders on December 8 and 9, 2002, titled "Registration/Approval and Coverage/Payment: Exploring Options for Improving Healthcare." This article arises from the discussion at this conference; it does not represent the official views of any person or institution involved. Although the group did not attempt to reach a consensus, it examined several important issues surrounding this regulatory debate. Herein are proposed options for enhancing regulatory efficiency through greater coordination between the FDA and CMS, and discussion of these proposals from the perspectives of members of both agencies, members of stakeholder organizations, and academic observers.

Biomedical Technology↗
PubMed2004

Economic impact of drug-eluting stents on hospital systems: a disease-state model.

BACKGROUND: Drug-eluting intracoronary stents decrease restenosis and later revascularization. The US Department of Health and Human Services (HHS), recognizing the financial and clinical impact of this technology, recently proposed accelerated reimbursement to hospitals. METHODS AND RESULTS: A disease state-transition computer model simulated the clinical and economic consequences to hospitals of drug-eluting stents over 5 years. Model parameters combined information from a longitudinal clinical database, a hospital cost-accounting system, and a survey instrument. Simulations were repeated 1000 times for each set of parameters. With 85% of stent procedures shifted to drug-eluting stents in the first year of availability, the mean number of repeat revascularizations dropped by 60.4% at year 5. With no changes in reimbursement policy, a hospital with a catheterization laboratory volume of 3112 patients yearly converted from a 2.01 million dollars (M) annual profit to an 8.10 M dollars loss in the first year (95% CI 8.09 M dollars to 8.12 M dollars) and 8.7 M dollars annual losses in later years. This represented an overall change in cash flow of 55.71 M dollars (95% CI 55.66 M dollars to 55.76 M dollars) away from the hospital over 5 years. The incremental reimbursement proposed by HHS reduced this loss to 4.75 M dollars in the first year and to 5.6 M dollars annually thereafter. In sensitivity analyses, the conversion of patients from bypass surgery to drug-eluting stents was the largest driver of overall cash flow shifts. CONCLUSIONS: Although Medicare has proposed to increase reimbursement to ease the impact of drug-eluting stents on hospitals, this increase will not totally offset the costs.

Angioplasty, Balloon, Coronary↗
PubMed2004

Prognostic value of predischarge electrocardiographic measurement of infarct size after thrombolysis: insights from GUSTO I Economics and Quality of Life substudy.

BACKGROUND: Current methods for risk stratification after acute myocardial infarction (MI) include several noninvasive studies. In this cost-containment era, the development of low-cost means should be encouraged. We assessed the ability of an electrocardiogram (ECG) MI-sizing score to predict outcomes in patients enrolled in the Economics and Quality of Life (EQOL) sub study of the Global Utilization of Streptokinase and Tissue plasminogen activator for Occluded coronary arteries -I (GUSTO-I) trial. METHODS: We classified patients by electrocardiographic Selvester QRS score at hospital discharge: those with a score 0-9 versus > or =10. Endpoints were 30-day and 1-year mortality, resource use, and quality-of-life measures. RESULTS: Patients with a QRS score <10 were well-matched with those with QRS score > or =10 with the exception of a trend to more anterior MI in the higher scored group. Patients with QRS score > or =10 had increased risk of death at 30-days (8.9% vs. 2.9% P < .001), and this difference persisted at 1 year (12.6% vs. 5.4%, P = .001). Recurrent chest pain, use of angiography, and angioplasty were similar during follow-up. However, there was a trend toward less coronary bypass surgery in patients with a QRS score > or =10. Readmission rates were higher at 30 days but similar at 1 year. CONCLUSIONS: Stratification of patients after acute MI by a simple measure of MI size identifies populations with different long-term prognoses; patients with a QRS score > or =10 (approximately 30% of the left ventricle infarcted) at discharge have poorer outcomes in both the short- and long-term. The standard 12-lead ECG provides a simple, economical means of risk stratification at discharge.

Electrocardiography↗
PubMed2004

Prospective study of perceived stress in cardiac patients.

BACKGROUND: Psychological stress is known to have a negative effect on the health and well-being of coronary artery disease (CAD) patients. Although the study of stress CAD samples has received considerable attention, few studies have examined the effects of gender and age, had multiple follow-ups over an extended period, and had extensive baseline assessment batteries. PURPOSE: In this study, demographic, clinical, social, and personality variables were evaluated as predictors of nine repeated assessments of stress over a 2-year period in 322 CAD patients (33.2% female). METHODS: At baseline, perceived social support, coping style, and social conflict were associated with stress ratings. Mixed models were used to evaluate predictors of reported stress during the subsequent 2 years. RESULTS: The results showed that higher stress was present in patients who were female and young. Follow-up stress was also found in patients with moderate income, congestive heart failure, high social conflict, low social support, and negative coping style. CONCLUSIONS: These findings may help clinicians identify patients who are likely to experience higher levels of stress over a prolonged period following a diagnosis of CAD and may also suggest which patients may benefit most from stress reduction interventions.

Adaptation, Psychological↗