Association of age and packed red blood cell transfusion to 1-year survival--an observational study of ICU patients.

OBJECTIVES: To compare the 1-year survival for different age strata of intensive care unit (ICU) patients after receipt of packed red blood cell (PRBC) transfusions. BACKGROUND: Despite guidelines documenting risks of PRBC transfusion and data showing that increasing age is associated with ICU mortality, little data exist on whether age alters the transfusion-related risk of decreased survival. METHODS: We retrospectively examined data on 2393 consecutive male ICU patients admitted to a tertiary-care hospital from 2003 to 2009 in age strata: 21-50, 51-60, 61-70, 71-80 and >80 years. We calculated Cox regression models to determine the modifying effect of age on the impact of PRBC transfusion on 1-year survival by using interaction terms between receipt of transfusion and age strata, controlling for type of admission and Charlson co-morbidity indices. We also examined the distribution of admission haematocrit and whether transfusion rates differed by age strata. RESULTS: All age strata experienced statistically similar risks of decreased 1-year survival after receipt of PRBC transfusions. However, patients age >80 were more likely than younger cohorts to have haematocrits of 25-30% at admission and were transfused at approximately twice the rate of each of the younger age strata. DISCUSSION: We found no significant interaction between receipt of red cell transfusion and age, as variables, and survival at 1 year as an outcome.

Potential cost-effectiveness of prophylactic use of the implantable cardioverter defibrillator or amiodarone after myocardial infarction.

BACKGROUND: Clinical trials have shown that implantable cardioverter defibrillators (ICDs) improve survival in patients with sustained ventricular arrhythmias. OBJECTIVE: To determine the efficacy necessary to make prophylactic ICD or amiodarone therapy cost-effective in patients with myocardial infarction. DESIGN: Markov model-based cost utility analysis. DATA SOURCES: Survival, cardiac death, and inpatient costs were estimated on the basis of the Myocardial Infarction Triage and Intervention registry. Other data were derived from the literature. TARGET POPULATION: Patients with past myocardial infarction who did not have sustained ventricular arrhythmia. TIME HORIZON: Lifetime. PERSPECTIVE: Societal. INTERVENTIONS: ICD or amiodarone compared with no treatment. OUTCOME MEASURES: Life-years, quality-adjusted life-years (QALYs), costs, number needed to treat, and incremental cost-effectiveness. RESULTS OF BASE-CASE ANALYSIS: Compared with no treatment, ICD use led to the greatest QALYs and the highest expenditures. Amiodarone use resulted in intermediate QALYs and costs. To obtain acceptable cost-effectiveness thresholds (

Medical therapy or coronary artery bypass graft surgery for chronic stable angina: an update using decision analysis.

PURPOSE: Randomized trials comparing medical and surgical therapies for the treatment of chronic stable angina were completed in the early 1980s. Therapies developed since then have decreased mortality and myocardial infarction rates from coronary artery disease. Using decision analysis and incorporating current recommendations for treatment, we simulated a trial comparing coronary artery bypass graft surgery and medical therapy. METHODS: A Markov decision analysis model was constructed to compare the 5-year and 10-year outcomes of a simulated trial of medical therapy versus bypass surgery for stable chronic angina. Baseline data were obtained from a meta-analysis of trials comparing the two treatments. Data on risk reduction from contemporary therapies were obtained from randomized trials and meta-analyses. RESULTS: All subgroups experienced modest gains in survival with current therapies. At 5 years, the survival rate was 90% in the medical group (an absolute gain of 6%) and 94% in the surgical group (an absolute gain of 4%). Similar results were obtained for patients with triple-vessel disease. Among patients with a low ejection fraction, the 5-year survival rate was 85% for medical patients and 92% for surgical patients. Sensitivity analyses did not substantially affect the conclusions. CONCLUSION: Advances in the treatment of chronic stable angina have improved the outcome both for patients treated initially with surgery and for those treated initially with medical therapy. The improvements were of similar magnitude in both groups, so the fundamental conclusions of the bypass trials are unchanged.

The prognostic value of troponin in patients with non-ST elevation acute coronary syndromes: a meta-analysis.

OBJECTIVES: This study was designed to compare the prognostic value of an abnormal troponin level derived from studies of patients with non-ST elevation acute coronary syndromes (ACS). BACKGROUND: Risk stratification for patients with suspected ACS is important for determining need for hospitalization and intensity of treatment. METHODS: We identified clinical trials and cohort studies of consecutive patients with suspected ACS without ST-elevation from 1966 through 1999. We excluded studies limited to patients with acute myocardial infarction and studies not reporting mortality or troponin results. RESULTS: Seven clinical trials and 19 cohort studies reported data for 5,360 patients with a troponin T test and 6,603 with a troponin I test. Patients with positive troponin (I or T) had significantly higher mortality than those with a negative test (5.2% vs. 1.6%, odds ratio [OR] 3.1). Cohort studies demonstrated a greater difference in mortality between patients with a positive versus negative troponin I (8.4% vs. 0.7%, OR 8.5) than clinical trials (4.8% if positive, 2.1% if negative, OR 2.6, p = 0.01). Prognostic value of a positive troponin T was also slightly greater for cohort studies (11.6% mortality if positive, 1.7% if negative, OR 5.1) than for clinical trials (3.8% if positive, 1.3% if negative, OR 3.0, p = 0.2) CONCLUSIONS: In patients with non-ST elevation ACS, the short-term odds of death are increased three- to eightfold for patients with an abnormal troponin test. Data from clinical trials suggest a lower prognostic value for troponin than do data from cohort studies.

Trends in treatment and outcomes for acute myocardial infarction: 1975-1995.

PURPOSE: To review the trends in treatment and survival for patients with acute myocardial infarction over the last 20 years. MATERIAL AND METHODS: Studies were identified through MEDLINE searches and review of study bibliographies. Additional data were obtained from the Health Care Financing Administration including data from Medicare claims files (part A). Thirty-day mortality rates were calculated using Medicare data and case fatality rates from the National Hospital Discharge Survey. Published meta-analyses were used to determine treatment effects. Published studies were included if they reported the use of therapies for acute myocardial infarction at a population level. Trends in the demographic characteristics of the patients as well as infarct characteristics, medication use, and revascularization were recorded. RESULTS: The use of acute treatments that are known to improve survival among patients with myocardial infarction has increased markedly during the last 20 years, leading to an estimated 9.6% reduction (from 27.0% to 17.4%) in 30-day mortality. After adjusting for potential interactions between therapies, the increase in use of aspirin, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and reperfusion can explain 71% of the decrease in the 30-day age- and sex-adjusted mortality rate from 1975 to 1995. The greatest effect of a given therapy was that of aspirin, which accounted for 34% of the decrease in 30-day mortality, followed by thrombolysis (17%), primary angioplasty (10%), beta-blockers (7%), and ACE inhibitors (3%). If other treatments (such as heparin or nonprimary angioplasty), whose effects on mortality are less certain, are included, up to 90% of the decrease in 30-day mortality can be explained by changes in treatment. CONCLUSIONS: The primary reason for the decrease in early mortality from myocardial infarction during the last 20 years appears to be increased use of effective treatments.

Health and economic benefits of increased beta-blocker use following myocardial infarction.

CONTEXT: beta-blockers are underused in patients who have myocardial infarction (MI), despite the proven efficacy of these agents. New evidence indicates that beta-blockers can have benefit in patients with conditions that have been considered relative contraindications. Understanding the consequences of underuse of beta-blockers is important because of the implications for current policy debates over quality-of-care measures and Medicare prescription drug coverage. OBJECTIVE: To examine the potential health and economic impact of increased use of beta-blockers in patients who have had MI. DESIGN AND SETTING: We used the Coronary Heart Disease (CHD) Policy Model, a computer-simulation Markov model of CHD in the US population, to estimate the epidemiological impact and cost-effectiveness of increased beta-blocker use from current to target levels among survivors of MI aged 35 to 84 years. Simulations included 1 cohort of MI survivors in 2000 followed up for 20 years and 20 successive annual cohorts of all first-MI survivors in 2000-2020. Mortality and morbidity from CHD were derived from published meta-analyses and recent studies. This analysis used a societal perspective. MAIN OUTCOME MEASURES: Prevented MIs, CHD mortality, life-years gained, and cost per quality-adjusted life-year (QALY) gained in 2000-2020. RESULTS: Initiating beta-blocker use for all MI survivors except those with absolute contraindications in 2000 and continuing treatment for 20 years would result in 4300 fewer CHD deaths, 3500 MIs prevented, and 45,000 life-years gained compared with current use. The incremental cost per QALY gained would be $4500. If this increase in beta-blocker use were implemented in all first-MI survivors annually over 20 years, beta-blockers would save $18 million and result in 72,000 fewer CHD deaths, 62,000 MIs prevented, and 447,000 life-years gained. Sensitivity analyses demonstrated that the cost-effectiveness of beta-blocker therapy would always be less than $11,000 per QALY gained, even under unfavorable assumptions, and may even be cost saving. Restricting beta-blockers only to ideal patients (those without absolute or relative contraindications) would reduce the epidemiological impact of beta-blocker therapy by about 60%. CONCLUSIONS: Our simulation indicates that increased use of beta-blockers after MI would lead to impressive gains in health and would be potentially cost saving. JAMA. 2000;284:2748-2754.

Does physician specialty affect the survival of elderly patients with myocardial infarction?

OBJECTIVE: To determine the effect of treatment by a cardiologist on mortality of elderly patients with acute myocardial infarction (AMI, heart attack), accounting for both measured confounding using risk-adjustment techniques and residual unmeasured confounding with instrumental variables (IV) methods. DATA SOURCES/STUDY SETTING: Medical chart data and longitudinal administrative hospital records and death records were obtained for 161,558 patients aged > or =65 admitted to a nonfederal acute care hospital with AMI from April 1994 to July 1995. Our principal measure of significant cardiologist treatment was whether a patient was admitted by a cardiologist. We use supplemental data to explore whether our analysis would differ substantially using alternative definitions of significant cardiologist treatment. STUDY DESIGN: This retrospective cohort study compared results using least squares (LS) multivariate regression with results from IV methods that accounted for additional unmeasured patient characteristics. Primary outcomes were 30-day and one-year mortality, and secondary outcomes included treatment with medications and revascularization procedures. DATA COLLECTION/EXTRACTION METHODS: Medical charts for the initial hospital stay of each AMI patient underwent a comprehensive abstraction, including dates of hospitalization, admitting physician, demographic characteristics, comorbid conditions, severity of clinical presentation, electrocardiographic and other diagnostic test results, contraindications to therapy, and treatments before and after AMI. PRINCIPAL FINDINGS: Patients admitted by cardiologists had fewer comorbid conditions and less severe AMIs. These patients had a 10 percent (95 percent CI: 9.5-10.8 percent) lower absolute mortality rate at one year. After multivariate adjustment with LS regression, the adjusted mortality difference was 2 percent (95 percent CI: 1.4-2.6 percent). Using IV methods to provide additional adjustment for unmeasured differences in risk, we found an even smaller, statistically insignificant association between physician specialty and one-year mortality, relative risk (RR) 0.96 (0.88-1.04). Patients admitted by a cardiologist were also significantly more likely to have a cardiologist consultation within the first day of admission and during the initial hospital stay, and also had a significantly larger share of their physician bills for inpatient treatment from cardiologists. IV analysis of treatments showed that patients treated by cardiologists were more likely to undergo revascularization procedures and to receive thrombolytic therapy, aspirin, and calcium channel-blockers, but less likely to receive beta-blockers. CONCLUSIONS: In a large population of elderly patients with AMI, we found significant treatment differences but no significant incremental mortality benefit associated with treatment by cardiologists.

Power Doppler imaging: initial evaluation as a screening examination for carotid artery stenosis.

PURPOSE: To evaluate power Doppler imaging as a possible screening examination for carotid artery stenosis. MATERIALS AND METHODS: In the principal pilot study, a prospective, blinded comparison of power Doppler imaging with duplex Doppler imaging, the reference-standard method, was conducted in 100 consecutive patients routinely referred for carotid artery imaging at a large, private multispecialty clinic. In the validation pilot study, a prospective, blinded comparison of power Doppler imaging with digital subtraction angiography, the reference-standard method, was conducted in 20 consecutive patients routinely referred at a teaching hospital. Using conservative assumptions, the authors performed cost-effectiveness analysis. RESULTS: Power Doppler imaging produced diagnostic-quality images in 89% of patients. When the images of the patients with nondiagnostic examinations were regarded as positive, power Doppler imaging had an area under the receiver operating characteristic curve, A(z), of 0.87, sensitivity of 70%, and specificity of 91%. The validation study results were very similar. The cost-effectiveness of screening and, as indicated, duplex Doppler imaging as the definitive diagnostic examination and endarterectomy was $47,000 per quality-adjusted life-year. CONCLUSION: The A(z) value for power Doppler imaging compares well with that for mammography, a generally accepted screening examination, and with most other imaging examinations. Power Doppler imaging is likely to be a reasonably accurate and cost-effective screening examination for carotid artery stenosis in asymptomatic populations.

Transesophageal echocardiography (TEE) in the critical care patient.

Critically ill patients often pose special diagnostic problems to the clinician, intensified by limited physical examination findings and difficulty in transportation to imaging suites. Mechanical ventilation and the limited ability to position the patient make transthoracic echocardiography difficult. Transesophageal echocardiographic (TEE) imaging, however, is well suited to the critical care patient and is frequently used to evaluate hemodynamic status, the presence of vegetations, a cardioembolic source, and an intracardiac cause of hypoxemia. Using proper precautions, TEE can be performed safely in unstable patients and frequently leads to important changes in management.

What a physician needs to know about cost-effectiveness.

The cost of medical care in the United States continues to spiral upward, partly as a result of new technological breakthroughs that promise improved length of life and quality of life for patients. But how good are these treatments in everyday practice? How do we make policies for adopting innovations that improve outcome but also increase costs? Cost-effectiveness studies are designed to answer these questions. They reveal important aspects of a particular medical decision and inform treatment choices by systematically analyzing the relationships between the costs and outcomes of alternative health care interventions. This article provides an introduction to the field of cost-effectiveness analysis and describes an approach to interpreting the rapidly proliferating cost-effectiveness literature.

Echocardiography in patients with suspected endocarditis: a cost-effectiveness analysis.

PURPOSE: We sought to determine the appropriate use of echocardiography for patients with suspected endocarditis. PATIENTS AND METHODS: We constructed a decision tree and Markov model using published data to simulate the outcomes and costs of care for patients with suspected endocarditis. RESULTS: Transesophageal imaging was optimal for patients who had a prior probability of endocarditis that is observed commonly in clinical practice (4% to 60%). In our base-case analysis (a 45-year-old man with a prior probability of endocarditis of 20%), use of transesophageal imaging improved quality-adjusted life expectancy (QALYs) by 9 days and reduced costs by $18 per person compared with the use of transthoracic echocardiography. Sequential test strategies that reserved the use of transesophageal echocardiography for patients who had an inadequate transthoracic study provided similar QALYs compared with the use of transesophageal echocardiography alone, but cost $230 to $250 more. For patients with prior probabilities of endocarditis greater than 60%, the optimal strategy is to treat for endocarditis without reliance on echocardiography for diagnosis. Patients with a prior probability of less than 2% should receive treatment for bacteremia without imaging. Transthoracic imaging was optimal for only a narrow range of prior probabilities (2% or 3%) of endocarditis. CONCLUSION: The appropriate use of echocardiography depends on the prior probability of endocarditis. For patients whose prior probability of endocarditis is 4% to 60%, initial use of transesophageal echocardiography provides the greatest quality-adjusted survival at a cost that is within the range for commonly accepted health interventions.

Effect of a home monitoring system on hospitalization and resource use for patients with heart failure.

BACKGROUND: Heart failure has a large medical and economic impact on the elderly. Past studies have shown that high-intensity multidisciplinary interventions at academic medical centers can reduce future hospitalizations. Our pilot study examined the effects of a low-intensity monitoring program on hospitalizations and cost of care for patients with heart failure treated by community physicians. METHODS: We enrolled 68 patients with heart failure (mean age 73 +/- 13 years, 53% male) monitored by 31 physicians in a multidisciplinary program of patient education, daily self-monitoring, and physician notification of abnormal weight gain, vital signs, and symptoms. Comparisons of medical claims were made between the patients who received the intervention and a control group of 86 patients matched to the intervention group on medical claims during the preceding year. RESULTS: Compared with the prior year, medical claims per year decreased in the intervention group ($8500 +/- $13,000 to $7400 +/- $11,400), whereas they increased in the control group ($9200 +/- $15,000 to $18,800 +/- $34,000, P <.05). Similar differences were observed for hospitalizations and total hospital days. The program's effectiveness was unrelated to age, sex, or type of left ventricular dysfunction. CONCLUSIONS: These findings suggest that a multidisciplinary program of patient education, monitoring, and physician notification can reduce resource use in patients with heart failure managed in a community setting.

Meta-analysis of trials comparing beta-blockers, calcium antagonists, and nitrates for stable angina.

CONTEXT: Which drug is most effective as a first-line treatment for stable angina is not known. OBJECTIVE: To compare the relative efficacy and tolerability of treatment with beta-blockers, calcium antagonists, and long-acting nitrates for patients who have stable angina. DATA SOURCES: We identified English-language studies published between 1966 and 1997 by searching the MEDLINE and EMBASE databases and reviewing the bibliographies of identified articles to locate additional relevant studies. STUDY SELECTION: Randomized or crossover studies comparing antianginal drugs from 2 or 3 different classes (beta-blockers, calcium antagonists, and long-acting nitrates) lasting at least 1 week were reviewed. Studies were selected if they reported at least 1 of the following outcomes: cardiac death, myocardial infarction, study withdrawal due to adverse events, angina frequency, nitroglycerin use, or exercise duration. Ninety (63%) of 143 identified studies met the inclusion criteria. DATA EXTRACTION: Two independent reviewers extracted data from selected articles, settling any differences by consensus. Outcome data were extracted a third time by 1 of the investigators. We combined results using odds ratios (ORs) for discrete data and mean differences for continuous data. Studies of calcium antagonists were grouped by duration and type of drug (nifedipine vs nonnifedipine). DATA SYNTHESIS: Rates of cardiac death and myocardial infarction were not significantly different for treatment with beta-blockers vs calcium antagonists (OR, 0.97; 95% confidence interval [CI], 0.67-1.38; P = .79). There were 0.31 (95% CI, 0.00-0.62; P = .05) fewer episodes of angina per week with beta-blockers than with calcium antagonists. beta-Blockers were discontinued because of adverse events less often than were calcium antagonists (OR, 0.72; 95% CI, 0.60-0.86; P<.001). The differences between beta-blockers and calcium antagonists were most striking for nifedipine (OR for adverse events with beta-blockers vs nifedipine, 0.60; 95% CI, 0.47-0.77). Too few trials compared nitrates with calcium antagonists or beta-blockers to draw firm conclusions about relative efficacy. CONCLUSIONS: beta-Blockers provide similar clinical outcomes and are associated with fewer adverse events than calcium antagonists in randomized trials of patients who have stable angina.

Prevention of hospitalizations for heart failure with an interactive home monitoring program.

Congestive heart failure is the most common cause of hospitalization for the older population. A previous study demonstrated that rehospitalizations, undertaken by 30% to 50% of elderly patients, can be prevented with intensive multidisciplinary intervention. A pilot study was designed to determine whether a less intensive program with patient education materials, automated reminders for medication compliance, self-monitoring of daily weights and vital signs, and facilitated telephone communication with a nurse-monitor could reduce hospitalizations and whether this benefit could be extended to younger outpatients. Twenty-seven male patients (mean age 62 years) with New York Heart Association class II to IV congestive heart failure caused by dilated cardiomyopathy underwent follow-up with an independent service, which provided the primary cardiologist with information concerning changes in vital signs or symptoms. The number of hospitalizations and hospital days during the mean value of 8.5 months in the program was compared patient by patient with the number during the equivalent period before entrance in the program. The number of hospitalizations for cardiovascular diagnoses and hospital days was reduced from 0.6 to 0.2 (p = 0.09) per patient year of follow-up and 7.8 to 0.7 days per patient per year (p < 0.05). Hospitalizations for all causes fell from 0.8 to 0.4 per patient per year (p = not significant) and 9.5 to 0.8 days per patient per year (p < 0.05). The greatest absolute and relative benefit was observed among patients with more severe congestive heart failure. The most frequent indication for intervention was an increase in weight, which was managed with adjustment of diuretic dosages. This preliminary experience suggests that close telephone monitoring by personnel from an independent service can prevent hospitalizations for heart failure among both recently discharged patients and ambulatory outpatients and among both elderly and middle-aged persons.

Design of a modular, extensible decision support system for arrhythmia therapy.

We developed a decision-support system for evaluation of treatment alternatives for supraventricular and ventricular arrhythmias. The system uses independent decision models that evaluate the costs and benefits of treatment for recurrent atrioventricular-node reentrant tachycardia (AVNRT), and of therapies to prevent sudden cardiac death (SCD) in patients at risk for life-threatening ventricular arrhythmias. Each of the decision models is accessible through a web-based interface that enables remote users to browse the model's underlying evidence and to perform analyses of effectiveness, cost effectiveness, and sensitivity to input variables. Because the web-based interface is independent of the models, we can extend the functionality of the system by adding decision models. This system illustrates that the use of a library of web-accessible decision models provides decision support economically to widely dispersed users.

Effect of beta-blockade on mortality in patients with heart failure: a meta-analysis of randomized clinical trials.

OBJECTIVES: We sought to evaluate the current evidence for an effect of beta-blockade treatment on mortality in patients with congestive heart failure (CHF). BACKGROUND: Although numerous small studies have suggested a benefit with beta-blocker therapy in patients with heart failure, a clear survival benefit has not been demonstrated. A recent combined analysis of several studies with the alpha- and beta-adrenergic blocking agent carvedilol demonstrated a significant survival advantage; however, the total number of events was small. Furthermore, it is unclear if previous studies with other beta-blockers are consistent with this finding. METHODS: Randomized clinical trials of beta-blockade treatment in patients with CHF from January 1975 through February 1997 were identified using a MEDLINE search and a review of reports from scientific meetings. Studies were included if mortality was reported during 3 or more months of follow-up. RESULTS: We identified 35 reports, 17 of which met the inclusion criteria. These studies included 3,039 patients with follow-up ranging from 3 months to 2 years. Beta-blockade was associated with a trend toward mortality reduction in 13 studies. When all 17 reports were combined, beta-blockade significantly reduced all-cause mortality (random effect odds ratio [OR] 0.69, 95% confidence interval [CI] 0.54 to 0.88). A trend toward greater treatment effect was noted for nonsudden cardiac death (OR 0.58, 95% CI 0.40 to 0.83) compared with sudden cardiac death (OR 0.84, 95% CI 0.59 to 1.2). Similar reductions in mortality were observed for patients with ischemic (OR 0.69, 95% CI 0.49 to 0.98) and nonischemic cardiomyopathy (OR 0.69, 95% CI 0.47 to 0.99). The survival benefit was greater for trials of the drug carvedilol (OR 0.54, 95% CI 0.36 to 0.81) than for noncarvedilol drugs (OR 0.82, 95% CI 0.60 to 1.12); however, the difference did not reach statistical significance (p = 0.10). CONCLUSIONS: Pooled evidence suggests that beta-blockade reduces all-cause mortality in patients with CHF. Additional trials are required to determine whether carvedilol differs in its effect from other agents.