Economics and cost-effectiveness in evaluating the value of cardiovascular therapies. Statistical issues in cost-effectiveness analysis.
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Cardiovascular Agents↗
Biomedical subjects
E R DeLong
Publications and source records attributed to E R DeLong.
Acute and long-term cost implications of coronary stenting.
OBJECTIVES: We compared the acute and one year medical costs and outcomes of coronary stenting with those for balloon angioplasty (percutaneous transluminal coronary angioplasty) in contemporary clinical practice. BACKGROUND: While coronary stent implantation reduces the need for repeat revascularization, it has been associated with significantly higher acute costs compared with coronary angioplasty. METHODS: We studied patients treated at Duke University between September 1995 and June 1996 who received either coronary stent (n = 384) or coronary angioplasty (n = 159) and met eligibility criteria. Detailed cost data were collected initially and up to one year following the procedure. Our primary analyses compared six and 12 month cumulative costs for coronary angioplasty- and stent-treated cohorts. We also compared treatment costs after excluding nontarget vessel interventions; after limiting analysis to those without prior revascularization; and after risk-adjusting cumulative cost estimates. RESULTS: Baseline clinical characteristics were generally similar between the two treatment groups. The mean in-hospital cost for stent patients was $3,268 higher than for those receiving coronary angioplasty ($14,802 vs. $11,534, p < 0.001). However, stent patients were less likely to be rehospitalized (22% vs. 34%, p = 0.002) or to undergo repeat revascularization (9% vs. 26%, p = 0.001) than coronary angioplasty patients within six months of the procedure. As such, mean cumulative costs at 6 months ($19,598 vs. $19,820, p = 0.18) and one year ($22,140 vs. $22,571, p = 0.26) were similar for the two treatments. Adjusting for baseline predictors of cost and selectively examining target vessel revascularization, or those without prior coronary intervention yielded similar conclusions. CONCLUSIONS: In contemporary practice, coronary stenting provides equivalent or better one-year patient outcomes without increasing cumulative health care costs.
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Use of a prognostic treadmill score in identifying diagnostic coronary disease subgroups.
BACKGROUND: Exercise testing is useful in the assessment of symptomatic patients for diagnosis of significant or extensive coronary disease and to predict their future risk of cardiac events. The Duke treadmill score (DTS) is a composite index that was designed to provide survival estimates based on results from the exercise test, including ST-segment depression, chest pain, and exercise duration. However, its usefulness for providing diagnostic estimates has yet to be determined. METHODS AND RESULTS: A logistic regression model was used to predict significant (>/=75% stenosis) and severe (3-vessel or left main) coronary artery disease, and a Cox regression analysis was used to predict cardiac survival. After adjustment for baseline clinical risk, the DTS was effectively diagnostic for significant (P<0.0001) and severe (P<0.0001) coronary artery disease. For low-risk patients (score >/=+5), 60% had no coronary stenosis >/=75% and 16% had single-vessel >/=75% stenosis. By comparison, 74% of high-risk patients (score <-11) had 3-vessel or left main coronary disease. Five-year mortality was 3%, 10%, and 35% for low-, moderate-, and high-risk DTS groups (P<0.0001). CONCLUSIONS: The composite DTS provides accurate diagnostic and prognostic information for the evaluation of symptomatic patients evaluated for clinically suspected ischemic heart disease.
Adult↗
Economic assessment of low-molecular-weight heparin (enoxaparin) versus unfractionated heparin in acute coronary syndrome patients: results from the ESSENCE randomized trial. Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q wave Coronary Events [unstable angina or non-Q-wave myocardial infarction].
BACKGROUND: In the ESSENCE trial, subcutaneous low-molecular-weight heparin (enoxaparin) reduced the 30-day incidence of death, myocardial infarction, and recurrent angina relative to intravenous unfractionated heparin in 3171 patients with acute coronary syndrome (unstable angina or non-Q-wave myocardial infarction). No increase in major bleeding was seen. METHODS AND RESULTS: Of the 936 ESSENCE patients randomized in the United States, 655 had hospital billing data collected. For the remainder, hospital costs were imputed with a multivariable linear regression model (R2=.86). Physician fees were estimated from the Medicare Fee Schedule. During the initial hospitalization, major resource use was reduced for enoxaparin patients, with the largest effect seen with coronary angioplasty (15% versus 20% for heparin, P=.04). At 30 days, these effects persisted, with the largest reductions seen in diagnostic catheterization (57% versus 63% for heparin, P=.04) and coronary angioplasty (18% versus 22%, P=.08). All resource use trends seen in the US cohort were also evident in the overall ESSENCE study population. In the United States, the mean cost of a course of enoxaparin therapy was $155, whereas that for heparin was $80. The total medical costs (hospital, physician, drug) for the initial hospitalization were $11 857 for enoxaparin and $12620 for heparin, a cost advantage for the enoxaparin arm of $763 (P=.18). At the end of 30 days, the cumulative cost savings associated with enoxaparin was $1172 (P=.04). In 200 bootstrap samples of the 30-day data, 94% of the samples showed a cost advantage for enoxaparin. CONCLUSIONS: In patients with acute coronary syndrome, low-molecular-weight heparin (enoxaparin) both improves important clinical outcomes and saves money relative to therapy with standard unfractionated heparin.
Acute Disease↗
The effects of New York's bypass surgery provider profiling on access to care and patient outcomes in the elderly.
OBJECTIVE: The aim of this study was to examine the effects of provider profiling on bypass surgery access and outcomes in elderly patients in New York. BACKGROUND: Since 1989, New York (NY) has compiled provider-specific bypass surgery mortality reports. While some have proposed that "provider profiling" has led to lower surgical mortality rates, critics have suggested that such programs lower in-state procedural access (increasing out-of-state transfers) without improving patient outcomes. METHODS: Using national Medicare data, we examined trends in the percentages of NY residents aged 65 years or older receiving out-of-state bypass surgery between 1987 and 1992 (before and after program initiation). We also examined in-state procedure use among elderly myocardial infarction patients during this period. Finally, we compared trends in surgical outcomes in NY Medicare patients with those for the rest of the nation. RESULTS: Between 1987 and 1992, the percentage of NY residents receiving bypass out-of-state actually declined (from 12.5% to 11.3%, p < 0.01 for trend). An elderly patient's likelihood for bypass following myocardial infarction in NY increased significantly since the program's initiation. Between 1987 and 1992, unadjusted 30-day mortality rates following bypass declined by 33% in NY Medicare patients compared with a 19% decline nationwide (p < 0.001). As a result of this improvement, NY had the lowest risk-adjusted bypass mortality rate of any state in 1992. CONCLUSIONS: We found no evidence that NY's provider profiling limited procedure access in NY's elderly or increased out-of-state transfers. Despite an increasing preoperative risk profile, procedural outcomes in NY improved significantly faster than the national average.
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The impact of choice of muscle relaxant on postoperative recovery time.
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Anesthesia Recovery Period↗
A comparison of 0.5% bupivacaine, 0.5% ropivacaine, and 0.75% ropivacaine for interscalene brachial plexus block.
UNLABELLED: The onset time and duration of action of ropivacaine during an interscalene block are not known. The potentially improved safety profile of ropivacaine may allow the use of higher concentrations to try and speed onset time. We compared bupivacaine and ropivacaine to determine the optimal long-acting local anesthetic and concentration for interscalene brachial plexus block. Seventy-five adult patients scheduled for outpatient shoulder surgery under interscalene block were entered into this double-blind, randomized study. Patients were assigned (n = 25 per group) to receive an interscalene block using 30 mL of 0.5% bupivacaine, 0.5% ropivacaine, or 0.75% ropivacaine. All solutions contained fresh epinephrine in a 1:400,000 concentration. At 1-min intervals after local anesthetic injection, patients were assessed to determine loss of shoulder abduction and loss of pinprick in the C5-6 dermatomes. Before discharge, patients were asked to document the time of first oral narcotic use, when incisional discomfort began, and when full sensation returned to the shoulder. The mean onset time of both motor and sensory blockade was <6 min in all groups. Duration of sensory blockade was similar in all groups as defined by the three recovery measures. We conclude that there is no clinically important difference in times to onset and recovery of interscalene block for bupivacaine 0.5%, ropivacaine 0.5%, and ropivacaine 0.75% when injected in equal volumes. IMPLICATIONS: In this study, we demonstrated a similar efficacy between equal concentrations of ropivacaine and bupivacaine. In addition, increasing the concentration of ropivacaine from 0.5% to 0.75% fails to improve the onset or duration of interscalene brachial plexus block.
Adult↗
Writing successful research proposals for medical science.
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Anesthesiology↗
Comparing risk-adjustment methods for provider profiling.
Risk-adjustment and provider profiling have become common terms as the medical profession attempts to measure quality and assess value in health care. One of the areas of care most thoroughly developed in this regard is quality assessment for coronary artery bypass grafting (CABG). Because in-hospital mortality following CABG has been studied extensively, risk-adjustment mechanisms are already being used in this area for provider profiling. This study compares eight different risk-adjustment methods as applied to a CABG surgery population of 28 providers. Five of the methods use an external risk-adjustment algorithm developed in an independent population, while the other three rely on an internally developed logistic model. The purposes of this study are to: (i) create a common metric by which to display the results of these various risk-adjustment methodologies with regard to dichotomous outcomes such as in-hospital mortality, and (ii) to compare how these risk-adjustment methods quantify the 'outlier' standing of providers. Section 2 describes the data, the external and internal risk-adjustment algorithms, and eight approaches to provider profiling. Section 3 then demonstrates the results of applying these methods on a data set specifically collected for quality improvement.
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Relationship between diabetes mellitus and long-term survival after coronary bypass and angioplasty.
BACKGROUND: Recent subgroup analyses of randomized trials have suggested that percutaneous intervention in diabetic patients with multivessel disease results in higher mortality than coronary artery bypass graft surgery (CABG). We studied the relationship between diabetes and survival after revascularization in a large prospective cohort of patients with multivessel coronary artery disease. METHODS AND RESULTS: By analyzing data for 3220 patients (24% diabetic) with symptomatic two- or three-vessel coronary disease who were undergoing percutaneous transluminal coronary angioplasty (PTCA) or CABG at Duke University Medical Center between 1984 and 1990, we found that at 5 years, unadjusted survival in the group of patients undergoing CABG was 74% in diabetics and 86% in nondiabetics. Similarly, 5-year survival among PTCA patients was 76% in diabetics and 88% in patients without diabetes. After adjustment for baseline characteristics, diabetic patients receiving either PTCA or CABG had significantly poorer survival than nondiabetics (chi2=43.56, P<.0001). Unlike previous studies, however, there was no significant differential effect of diabetes on outcome between patients treated with PTCA and those treated with CABG (chi2=0.01, P=.91). CONCLUSIONS: Although diabetes was associated with a worse long-term outcome after both PTCA and CABG in patients with multivessel coronary artery disease, the effect of diabetes on prognosis was similar in both treatment groups. Thus, our findings support the concept that the choice of initial revascularization strategy should not be based exclusively on a history of diabetes but rather should rely on other factors, such as angiographic suitability and clinical status.
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Relationship between physician and hospital coronary angioplasty volume and outcome in elderly patients.
BACKGROUND: With the expectation that physicians who perform larger numbers of coronary angioplasty procedures will have better outcomes, the American College of Cardiology/ American Heart Association guidelines recommend minimum physician volumes of 75 procedures per year. However, there is little empirical data to support this recommendation. METHODS AND RESULTS: We examined in-hospital bypass surgery and death after angioplasty according to 1992 physician and hospital Medicare procedure volume. In 1992, 6115 physicians performed angioplasty on 97,478 Medicare patients at 984 hospitals. The median numbers of procedures performed per physician and per hospital were 13 (interquartile range, 5 to 25) and 98 (interquartile range, 40 to 181), respectively. With the assumption that Medicare patients composed one half to one third of all patients undergoing angioplasty, these median values are consistent with an overall physician volume of 26 to 39 cases per year and an overall hospital volume of 196 to 294 cases per year. After adjusting for age, sex, race, acute myocardial infarction, and comorbidity, low-volume physicians were associated with higher rates of bypass surgery (P < .001) and low-volume hospitals were associated with higher rates of bypass surgery and death (P < .001). Improving outcomes were seen up to threshold values of 75 Medicare cases per physician and 200 Medicare cases per hospital. CONCLUSIONS: More than 50% of physicians and 25% of hospitals performing coronary angioplasty in 1992 were unlikely to have met the minimum volume guidelines first published in 1988, and these patients had worse outcomes. While more recent data are required to determine whether the same relationships persist after the introduction of newer technologies, this study suggests that adherence to minimum volume standards by physicians and hospitals will lead to better outcomes for elderly patients undergoing coronary angioplasty.
Age Factors↗
Racial variation in the use of coronary-revascularization procedures. Are the differences real? Do they matter?
BACKGROUND: Studies have reported that blacks undergo fewer coronary-revascularization procedures than whites, but it is not clear whether the clinical characteristics of the patients account for these differences or whether they indicate underuse of the procedures in blacks or overuse in whites. METHODS: In a study at Duke University of 12,402 patients (10.3 percent of whom were black) with coronary disease, we calculated unadjusted and adjusted rates of angioplasty and bypass surgery in blacks and whites after cardiac catheterization. We also examined patterns of treatment after stratifying the patients according to the severity of disease, angina status, and estimated survival benefit due to revascularization. Finally, we compared five-year survival rates in blacks and whites. RESULTS: After adjustment for the severity of disease and other characteristics, blacks were 13 percent less likely than whites to undergo angioplasty and 32 percent less likely to undergo bypass surgery. The adjusted black:white odds ratios for receiving these procedures were 0.87 (95 percent confidence interval, 0.73 to 1.03) and 0.68 (95 percent confidence interval, 0.56 to 0.82), respectively. The racial differences in rates of bypass surgery persisted among those with severe anginal symptoms (31 percent of blacks underwent surgery, vs. 45 percent of whites, P<0.001) and among those predicted to have the greatest survival benefit from revascularization (42 percent vs. 61 percent, P<0.001). Finally, unadjusted and adjusted rates of survival for five years were significantly lower in blacks than in whites. CONCLUSIONS: Blacks with coronary disease were significantly less likely than whites to undergo coronary revascularization, particularly bypass surgery - a difference that could not be explained by the clinical features of their disease. The differences in treatment were most pronounced among those predicted to benefit the most from revascularization. Since these differences also correlated with a lower survival rate in blacks, we conclude that coronary revascularization appears to be underused in blacks.
Angioplasty, Balloon, Coronary↗
Impact of early discharge after coronary artery bypass graft surgery on rates of hospital readmission and death. The Ischemic Heart Disease (IHD) Patient Outcomes Research Team (PORT) Investigators.
OBJECTIVES: This study examined the impact of early hospital discharge on short-term clinical outcomes of elderly patients treated with coronary artery bypass graft surgery (CABG) in the United States in 1992. BACKGROUND: Protocols that encourage earlier discharge of patients who have had CABG have been implemented across the country. Although delivery of efficient care benefits both patients and providers, premature discharge can adversely affect clinical outcomes, resulting in increased hospital readmissions and higher long-term costs. METHODS: We examined the prevalence of early discharge (postoperative length of stay < or = 5 days) among 83,347 non-health maintenance organization (HMO) Medicare patients who underwent CABG in the United States in 1992. Using logistic regression models, we identified patient characteristics associated with early discharge and obtained risk-adjusted rates of death and readmission or death for postoperative lengths of stay between 4 and 14 days. RESULTS: In 1992, 6% of Medicare patients undergoing CABG were discharged within 5 days of the operation. The prevalence of early discharge varied considerably among states, ranging from 1% to 21%. Patients discharged early tended to be younger and male and have fewer comorbid illnesses. Risk-adjusted rates of death and death or cardiovascular readmission were lowest among patients discharged early. CONCLUSIONS: As of 1992, early discharge of elderly patients treated with CABG in non-HMO settings was not associated with higher 60-day rates of death or readmission. This suggests that physicians were able to identify low risk candidates for early discharge. Variation across the nation in early discharge rates, along with the percentage of patients without major risk factors for adverse outcomes, suggests that higher rates of early discharge might be safely achieved.
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Geographic variation in resource use for coronary artery bypass surgery. IHD Port Investigators.
OBJECTIVES: The purpose of this study was to examine the national variability in patient-level cost and length of stay for coronary artery bypass grafting (CABG) in Medicare patients. METHODS: Retrospective multivariate regression analysis was done using Medicare administrative files and American Hospital Association files. Patients in the study had an International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedure code for CABG, with accompanying 1990 procedure data, in the Medicare Provider Analysis and Review File (n = 92,449). RESULTS: Outcome measures used were inpatient cost (exclusive of professional fees) and inpatient length of stay associated with bypass admission. The national average cost of bypass surgery was $22,847 (median $18,783), with an accompanying average length of stay of 16 days (median 13 days). Multivariate regression analysis revealed that patient-level cost and length of stay were related to clinical, demographic, hospital, and regional characteristics (R2 = 25% and 16%, respectively). After accounting for these characteristics at the patient level, considerable variation among states persisted in both cost and length of stay. In addition, states with similar adjusted lengths of stay varied widely with respect to adjusted cost. No relation was found at the state level between level of resource use and either procedural mortality or 60-day mortality/readmission rates. CONCLUSIONS: Considerable variability exists among states in patient-level cost and length of stay for CABG surgery, after adjusting to the extent possible for clinical, demographic, hospital, and regional characteristics. The lack of association at the state level between resource use and rates of mortality and hospital readmission suggests that costs could be reduced in many areas of the United States without compromising quality of care.
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Outcome of acute myocardial infarction according to the specialty of the admitting physician.
BACKGROUND: In order to limit costs, health care organizations in the United States are shifting medical care from specialists to primary care physicians. Although primary care physicians provide less resource-intensive care, there is little information concerning the effects of this strategy on outcomes. METHODS: We examined mortality according to the specialty of the admitting physician among 8241 Medicare patients who were hospitalized for acute myocardial infarction in four states during a seven-month period in 1992. Proportional-hazards regression models were used to examine survival up to one year after the myocardial infarction. To determine the generalizability of our findings, we also examined insurance claims and survival data for all 220,535 patients for whom there were Medicare claims for hospital care for acute myocardial infarction in 1992. RESULTS: After adjustment for characteristics of the patients and hospitals, patients who were admitted to the hospital by a cardiologist were 12 percent less likely to die within one year than those admitted by a primary care physician (P<0.001). Cardiologists also had the highest rate of use of cardiac procedures and medications, including medications (such as thrombolytic agents and beta-blockers) that are associated with improved survival. CONCLUSIONS: Health care strategies that shift the care of elderly patients with myocardial infarction from cardiologists to primary care physicians lower rates of use of resources (and potentially lower costs), but they may also cause decreased survival. Additional information is needed to elucidate how primary care physicians and specialists should interact in the care of severely ill patients.
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Impact of an interactive video on decision making of patients with ischemic heart disease.
An experimental pilot study using repeated measures to examine the impact of an interactive video program on the decision making of patients with ischemic heart disease was carried on at a tertiary care center and a Veterans Affairs hospital. The patients (n = 80, mean age 61.1 years, 77% male, 75% white, 26.7% with acute myocardial infarction), who had undergone diagnostic cardiac catheterization and were found to have significant coronary artery disease (> or = 75% stenosis in at least one vessel), watched the Shared Decision-Making Program (SDP) for Ischemic Heart Disease (IHD), a novel interactive video system designed to provide information necessary for patients to participate actively in decision making. This program compares medical therapy, angioplasty, and bypass surgery through a physician narrator, patient testimonials, and empirically-based, patient-specific outcome estimates of short-time complications and long-term survival. Before and after viewing the SDP, patients completed surveys containing multiple choice questions and Likert scales. They rated the program as more helpful than all other decision aids except the physician, and after viewing the SDP they expressed increased confidence in their treatment choice and decreased confidence in alternative options (p = .0001). The greatest effects appeared to be concentrated in those patients with less education (p = .04), and the program appeared to increase anxiety in nonwhite patients compared with white patients (p = 0.07).
Decision Making↗
Predicting the presence of choledocholithiasis in patients with symptomatic cholelithiasis.
OBJECTIVES: Accurate preoperative prediction of choledocholithiasis is essential in order to minimize patient risk and curtail health care expenditures. This study was designed to identify independent risk factors for choledocholithiasis in patients who had undergone cholecystectomy for symptomatic cholelithiasis and to develop a predictive model based on those factors. METHODS: The charts of 1264 consecutive patients who had undergone cholecystectomy at one of three North Carolina hospitals between January 1, 1989 and December 31, 1991 were reviewed; 465 of these patients had confirmed presence or absence of choledocholithiasis by cholangiography and/or common bile duct exploration and were eligible for analysis. Candidate predictor variables included age and maximum preoperative values for each of the following: temperature, alkaline phosphatase, bilirubin, AST, amylase, white blood cell count, and common bile duct diameter. Model development and validation were conducted using standard data-splitting (60% "training," 40% "test") and logistic regression techniques. RESULTS: Choledocholithiasis was confirmed in 115 (25%) of the 465 eligible patients. Univariate analysis identified bilirubin, common bile duct diameter, AST, temperature, alkaline phosphatase, and age as predictors. Multivariable analysis subsequently identified bilirubin, common bile duct diameter, AST, alkaline phosphatase, and age as independent predictors of choledocholithiasis. A final model containing these variables (except age, whose contribution to the model was small) accurately predicted choledocholithiasis (c-index = 0.76). CONCLUSIONS: Accurate estimates of choledocholithiasis risk can be made using maximum preoperative bilirubin, common bile duct diameter, AST, and alkaline phosphatase values. Use of the model may help physicians select those patients with symptomatic cholelithiasis who would most likely benefit from further investigation to exclude choledocholithiasis.
Case-Control Studies↗
Outcomes of coronary artery bypass graft surgery in 24,461 patients aged 80 years or older.
BACKGROUND: Coronary artery bypass graft surgery is increasingly common in patients of age > or = 80 years. Single-institution reviews have cited a wide range of mortality results after bypass surgery in this age group, in part because of limited sample sizes. Using claims data, we examined recent national trends in the use and outcomes of bypass surgery in the very elderly. METHODS AND RESULTS: From an examination of Medicare data from 1987 through 1990, we identified 24,461 patients of age > or = 80 years who underwent bypass surgery. We compared surgical outcomes in these patients with those in Medicare patients of age 65 to 70 years. We found that the national use of bypass surgery in patients of age > or = 80 years increased 67% between 1987 and 1990. Compared with patients of age 65 to 70 years, the very elderly had significantly longer postoperative hospital stays (mean, 14.3 versus 10.4 days), higher charges (mean, $48,200 versus $38,000), and greater costs (mean, $27,200 versus $21,700). In-hospital (11.5% versus 4.4%), 1-year (19.3% versus 7.9%), and 3-year mortality rates (28.8% versus 13.1%) after bypass surgery were also significantly higher in patients of age > or = 80 years compared with younger patients. Although their initial surgical risk was high, octogenarians who underwent bypass surgery had a long-term survival rate similar to that of the general US octogenarian population. CONCLUSIONS: The use of bypass surgery in patients of age > or = 80 years in increasing. These very elderly patients face high surgical risks and accumulate significant hospital expenses. Further research is indicated to determine whether the long-term benefits from bypass surgery in the very elderly outweigh the increased procedural risks.
Age Factors↗