Scholars@Duke
Elizabeth Ray DeLong

Elizabeth Ray DeLong

Professor Emeritus of Biostatistics & Bioinformatics
Biostatistics & Bioinformatics, Division of Biostatistics
delon001@mc.duke.edu
Duke Box 2721, Durham, NC 27710
11072 Hock Plaza, Durham, NC 27710

Featured Works

Hypercholesterolemia paradox in relation to mortality in acute coronary syndrome.

Journal article Clin Cardiol · September 2009 Featured Publication BACKGROUND: Hypercholesterolemia is a risk factor for coronary artery disease, yet is associated with lower risk of adverse outcomes in patients with acute coronary syndromes (ACS). HYPOTHESIS: We explored this paradox in 84,429 patients with non-ST-segmen ... Full text Link to item Cite

Assessing the economic attractiveness of coronary artery revascularization in chronic kidney disease patients.

Journal article J Med Syst · August 2009 Featured Publication Chronic kidney disease (CKD) is associated with increased morbidity and mortality in coronary artery disease (CAD) patients. We compared the economic attractiveness of CAD revascularization procedures in patients with and without CKD. Our population includ ... Full text Link to item Cite

The Society of Thoracic Surgeons 2008 cardiac surgery risk models: part 1--coronary artery bypass grafting surgery.

Journal article Ann Thorac Surg · July 2009 Featured Publication BACKGROUND: The first version of The Society of Thoracic Surgeons National Adult Cardiac Surgery Database (STS NCD) was developed nearly 2 decades ago. Since its inception, the number of participants has grown dramatically, patient acuity has increased, an ... Full text Link to item Cite

The Society of Thoracic Surgeons 2008 cardiac surgery risk models: part 2--isolated valve surgery.

Journal article Ann Thorac Surg · July 2009 Featured Publication BACKGROUND: Adjustment for case-mix is essential when using observational data to compare surgical techniques or providers. That is most often accomplished through the use of risk models that account for preoperative patient factors that may impact outcome ... Full text Link to item Cite

The Society of Thoracic Surgeons 2008 cardiac surgery risk models: part 3--valve plus coronary artery bypass grafting surgery.

Journal article Ann Thorac Surg · July 2009 Featured Publication BACKGROUND: Since 1999, The Society of Thoracic Surgeons (STS) has published two risk models that can be used to adjust the results of valve surgery combined with coronary artery bypass graft surgery (CABG). The most recent was developed from data for pati ... Full text Link to item Cite

Strategies for analyzing multilevel cluster-randomized studies with binary outcomes collected at varying intervals of time.

Journal article Stat Med · December 20, 2008 Featured Publication Frequently, studies are conducted in a real clinic setting. When the outcome of interest is collected longitudinally over a specified period of time, this design can lead to unequally spaced intervals and varying numbers of assessments. In our study, these ... Full text Link to item Cite

Patterns of transfer for patients with non-ST-segment elevation acute coronary syndrome from community to tertiary care hospitals.

Journal article Am Heart J · July 2008 Featured Publication BACKGROUND: Practice guidelines for non-ST-segment elevation acute coronary syndromes (NSTE ACS) recommend early invasive management (cardiac catheterization and revascularization within 48 hours of hospital presentation) for high-risk patients, but interh ... Full text Link to item Cite

Impact of case volume on hospital performance assessment.

Journal article Arch Intern Med · June 23, 2008 Featured Publication BACKGROUND: Process performance measures are increasingly used to assess and reward hospital quality. The impact of small hospital case volumes on such measures is not clear. METHODS: Using data from the Hospital Quality Alliance, we examined hospital perf ... Full text Link to item Cite

Exploring the behavior of hospital composite performance measures: an example from coronary artery bypass surgery.

Journal article Circulation · December 18, 2007 Featured Publication BACKGROUND: Composite scores that combine several performance measures into a single ranking are becoming the accepted metric for assessing hospital performance. In particular, the Centers for Medicare & Medicaid Services Hospital Quality Incentive Demonst ... Full text Link to item Cite

Pay for performance, quality of care, and outcomes in acute myocardial infarction.

Journal article JAMA · June 6, 2007 Featured Publication CONTEXT: Pay for performance has been promoted as a tool for improving quality of care. In 2003, the Centers for Medicare & Medicaid Services (CMS) launched the largest pay-for-performance pilot project to date in the United States, including indicators fo ... Full text Link to item Cite

Is early too early? Effect of shorter stays after bypass surgery.

Journal article Ann Thorac Surg · January 2007 Featured Publication BACKGROUND: Postoperative stays after coronary artery bypass graft surgery (CABG) decreased substantially in the 1990s. Although shorter stays offer clinical benefits, premature discharge could increase adverse events and offset initial savings. This study ... Full text Link to item Cite

Trends in postoperative length of stay after bypass surgery.

Journal article Am Heart J · December 2006 Featured Publication BACKGROUND: Although single-site studies have reported reductions in coronary artery bypass graft (CABG) surgery length of stay (LOS) over the last 15 years, less information is available regarding overall temporal trends and interhospital variability. Thi ... Full text Link to item Cite

Insurance coverage and care of patients with non-ST-segment elevation acute coronary syndromes.

Journal article Ann Intern Med · November 21, 2006 Featured Publication BACKGROUND: The impact of insurance coverage on the care of patients with non-ST-segment elevation acute coronary syndromes (NSTE ACS) is unclear. OBJECTIVE: To compare NSTE ACS care patterns by insurance type. DESIGN: Comparison of Medicaid patients young ... Full text Link to item Cite

Selection of surgical or percutaneous coronary intervention provides differential longevity benefit.

Journal article Ann Thorac Surg · October 2006 Featured Publication BACKGROUND: Treatment of coronary artery disease (CAD) is evolving with better medications, improvements in percutaneous coronary intervention (PCI), and enhanced techniques for coronary artery bypass grafting (CABG). METHODS: In this study, 18,481 patient ... Full text Link to item Cite

Multifaceted intervention to promote beta-blocker use in heart failure.

Journal article Am Heart J · May 2006 Featured Publication BACKGROUND: Despite a survival benefit and guideline recommendation for beta-blockers in left ventricular systolic dysfunction, beta-blockers are underused in clinical practice. METHODS: Medical practices with > or = 15 patients with heart failure (HF) in ... Full text Link to item Cite

Association between hospital process performance and outcomes among patients with acute coronary syndromes.

Journal article JAMA · April 26, 2006 Featured Publication CONTEXT: Selected care processes are increasingly being used to measure hospital quality; however, data regarding the association between hospital process performance and outcomes are limited. OBJECTIVES: To evaluate contemporary care practices consistent ... Full text Link to item Cite

Determinants of operative mortality in valvular heart surgery.

Journal article J Thorac Cardiovasc Surg · March 2006 Featured Publication OBJECTIVE: In some respects, outcome reporting in valvular surgery has been hampered by focusing on specific populations, reluctance to publish high-risk subgroups, and possibly skewed or inadequate samples. The goal of this study was to evaluate risk fact ... Full text Link to item Cite

Long-term adherence to evidence-based secondary prevention therapies in coronary artery disease.

Journal article Circulation · January 17, 2006 Featured Publication BACKGROUND: Studies have examined the use of evidence-based therapies for coronary artery disease (CAD) in the short term and at hospital discharge, but few have evaluated long-term use. METHODS AND RESULTS: Using the Duke Databank for Cardiovascular Disea ... Full text Link to item Cite

Detecting pheochromocytoma: defining the most sensitive test.

Journal article Ann Surg · January 2006 Featured Publication OBJECTIVE: To define the most sensitive biochemical test to establish the diagnosis of pheochromocytoma and also to assess the potential role of iodine 131-labeled metaiodobenzylguanidine scintigraphy (I-MIBG) in the diagnosis of this tumor. SUMMARY BACKGR ... Full text Link to item Cite

The evaluation of treatment when center-specific selection criteria vary with respect to patient risk.

Journal article Biometrics · December 2005 Featured Publication Many standards of medical care are based on the demonstrated effects of various treatment strategies or processes. Unlike pharmacological treatments, these strategies or processes are not necessarily subjected to rigorous clinical trials and their benefit ... Full text Link to item Cite

Optimal timing of intervention in non-ST-segment elevation acute coronary syndromes: insights from the CRUSADE (Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA guidelines) Registry.

Journal article Circulation · November 15, 2005 Featured Publication BACKGROUND: Recent studies indicate that a routine invasive approach for patients with unstable angina (UA) and non-ST-segment elevation myocardial infarction (NSTEMI) yields improved outcomes compared with a conservative approach, but the optimal timing o ... Full text Link to item Cite

Predicting risk-adjusted mortality for CABG surgery: logistic versus hierarchical logistic models.

Journal article Med Care · July 2005 Featured Publication BACKGROUND: In recent years, several studies in the medical and health service research literature have advocated the use of hierarchical statistical models (multilevel models or random-effects models) to analyze data that are nested (eg, patients nested w ... Full text Link to item Cite

Influence of racial disparities in procedure use on functional status outcomes among patients with coronary artery disease.

Journal article Circulation · March 15, 2005 Featured Publication BACKGROUND: Although black cardiac patients receive fewer revascularization procedures than whites, it is unclear whether this has a detrimental impact on outcomes. The objective of our study was to compare 6-month functional status and angina outcomes amo ... Full text Link to item Cite

Interpreting statistics in medical literature: a vade mecum for surgeons.

Journal article J Am Coll Surg · March 2004 Featured Publication Full text Link to item Cite

Postconception age and other risk factors associated with mortality following Gram-negative rod bacteremia.

Journal article J Perinatol · March 2004 Featured Publication BACKGROUND: Neonatal nosocomial Gram-negative rod bacteremia (GNR-b) is considered ominous. DESIGN: Multi-center cohort study of premature infants (N=6172) who had a blood culture after day of life 3 and whose birthweight was < or =1250 g. RESULTS: A total ... Full text Link to item Cite

Economic effects of beta-blocker therapy in patients with heart failure.

Journal article Am J Med · January 15, 2004 Featured Publication PURPOSE: Studies suggest that beta-blockers improve outcomes in heart failure patients and may be cost saving to society. However, many heart failure patients are not treated with beta-blockers. Economic incentives facing hospitals, physicians, payers, and ... Full text Link to item Cite

Procedural volume as a marker of quality for CABG surgery.

Journal article JAMA · January 14, 2004 Featured Publication CONTEXT: There have been recent calls for using hospital procedural volume as a quality indicator for coronary artery bypass graft (CABG) surgery, but further research into analysis and policy implication is needed before hospital procedural volume is acce ... Full text Link to item Cite

ROC methodology within a monitoring framework.

Journal article Stat Med · November 30, 2003 Featured Publication Receiver operating characteristic (ROC) methodology is widely used to evaluate and compare diagnostic tests. Generally, each diagnostic test is applied once to each subject in a population and the results, reported on a continuous scale, are used to constr ... Full text Link to item Cite

Empirical therapy for neonatal candidemia in very low birth weight infants.

Journal article Pediatrics · September 2003 Featured Publication OBJECTIVE: Neonatal candidemia is often fatal. Empirical antifungal therapy is associated with improved survival in neonates and patients with fever and neutropenia. Although guidelines for empirical therapy exist for patients with fever and neutropenia, t ... Full text Link to item Cite

Use of continuous quality improvement to increase use of process measures in patients undergoing coronary artery bypass graft surgery: a randomized controlled trial.

Journal article JAMA · July 2, 2003 Featured Publication CONTEXT: A rigorous evaluation of continuous quality improvement (CQI) in medical practice has not been carried out on a national scale. OBJECTIVE: To test whether low-intensity CQI interventions can be used to speed the national adoption of 2 coronary art ... Full text Link to item Cite

The Society of Thoracic Surgeons: 30-day operative mortality and morbidity risk models.

Journal article Ann Thorac Surg · June 2003 Featured Publication BACKGROUND: Although 30 day risk-adjusted operative mortality (ROM) has been used for quality assessment, it is not sufficient to describe the outcomes after coronary artery bypass grafting (CABG) surgery. Risk-adjusted major morbidity may differentially i ... Full text Link to item Cite

Percutaneous transluminal septal reduction for hypertrophic obstructive cardiomyopathy: report from an international pilot study.

Journal article J Med Syst · August 2002 Featured Publication Assessing the effectiveness of newer treatments for rare diseases can be challenging because of the small number of patients treated at individual centers. We enrolled patients undergoing percutaneous transluminal septal myocardial ablation (PTSMA) for hyp ... Full text Link to item Cite

Hospital variability in length of stay after coronary artery bypass surgery: results from the Society of Thoracic Surgeon's National Cardiac Database.

Journal article Ann Thorac Surg · August 2002 Featured Publication BACKGROUND: There is growing interest in comparing resource, as well as patient outcome metrics among coronary artery bypass graft surgery (CABG) providers, yet few tools exist for adjusting these provider comparisons for patient case-mix. In this study, w ... Full text Link to item Cite

Patient-reported frequency of taking aspirin in a population with coronary artery disease.

Journal article Am J Cardiol · May 1, 2002 Featured Publication Despite the established benefits of antiplatelet agents in coronary artery disease (CAD), many appropriate patients are not receiving them. We investigated the prevalence of and factors associated with aspirin use and nonuse within a large referral populat ... Full text Link to item Cite

Association between pulse pressure and mortality in patients undergoing maintenance hemodialysis.

Journal article JAMA · March 27, 2002 Featured Publication CONTEXT: Although increased blood pressure is associated with adverse outcomes in the general population, elevated blood pressure is associated with decreased mortality in patients with end-stage renal disease undergoing maintenance hemodialysis. Recent in ... Full text Link to item Cite

Underuse of aspirin in a referral population with documented coronary artery disease.

Journal article Am J Cardiol · March 15, 2002 Featured Publication Despite substantial evidence that antiplatelet therapy saves lives and reduces adverse events in patients with coronary artery disease (CAD), use of the most widely available and lowest cost antiplatelet agent, aspirin, continues to be disappointingly low. ... Full text Link to item Cite

A decade of change--risk profiles and outcomes for isolated coronary artery bypass grafting procedures, 1990-1999: a report from the STS National Database Committee and the Duke Clinical Research Institute. Society of Thoracic Surgeons.

Journal article Ann Thorac Surg · February 2002 Featured Publication BACKGROUND: The Society of Thoracic Surgeons National Adult Cardiac Database is the largest voluntary clinical database in medicine. Using this database we examined changes in the risk profile of patients undergoing isolated coronary artery bypass grafting ... Full text Link to item Cite

Variability in cost of coronary bypass surgery in New York State: potential for cost savings.

Journal article Am Heart J · January 2002 Featured Publication OBJECTIVE: Previous analyses of variability in bypass resource use have not focused on hospital-level variation or adequately explored the influence of patient risk. We combined a clinical database with claims data to fully characterize patient level and h ... Full text Link to item Cite

The impact of statistical adjustment on economic profiles of interventional cardiologists.

Journal article J Am Coll Cardiol · November 1, 2001 Featured Publication OBJECTIVES: The objective of this study was to identify preprocedure patient factors associated with percutaneous intervention costs and to examine the impact of these patient factors on economic profiles of interventional cardiologists. BACKGROUND: There ... Full text Link to item Cite

Using observational data to estimate prognosis: an example using a coronary artery disease registry.

Journal article Stat Med · August 30, 2001 Featured Publication With the proliferation of clinical data registries and the rising expense of clinical trials, observational data sources are increasingly providing evidence for clinical decision making. These data are viewed as complementary to randomized clinical trials ... Full text Link to item Cite

Sex differences in neurological outcomes and mortality after cardiac surgery: a society of thoracic surgery national database report.

Journal article Circulation · May 1, 2001 Featured Publication BACKGROUND: The purpose of this study was to evaluate whether women undergoing cardiac surgery are more likely to suffer neurological complications than men and whether these complications could explain, at least in part, their higher perioperative mortali ... Full text Link to item Cite

Prediction of operative mortality after valve replacement surgery.

Journal article J Am Coll Cardiol · March 1, 2001 Featured Publication OBJECTIVES: We sought to develop national benchmarks for valve replacement surgery by developing statistical risk models of operative mortality. BACKGROUND: National risk models for coronary artery bypass graft surgery (CABG) have gained widespread accepta ... Full text Link to item Cite