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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 for acute myocardial infarction.Objective: To determine if pay for performance was associated with either improved processes of care and outcomes or unintended consequences for acute myocardial infarction at hospitals participating in the CMS pilot project.Design, Setting, and Participants: An observational, patient-level analysis of 105,383 patients with acute non-ST-segment elevation myocardial infarction enrolled in the Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the American College of Cardiology/American Heart Association (ACC/AHA) Guidelines (CRUSADE) national quality-improvement initiative. Patients were treated between July 1, 2003, and June 30, 2006, at 54 hospitals in the CMS program and 446 control hospitals.Main Outcome Measures: The differences in the use of ACC/AHA class I guideline recommended therapies and in-hospital mortality between pay for performance and control hospitals.Results: Among treatments subject to financial incentives, there was a slightly higher rate of improvement for 2 of 6 targeted therapies at pay-for-performance vs control hospitals (odds ratio [OR] comparing adherence scores from 2003 through 2006 at half-year intervals for aspirin at discharge, 1.31; 95% confidence interval [CI], 1.18-1.46 vs OR, 1.17; 95% CI, 1.12-1.21; P = .04) and for smoking cessation counseling (OR, 1.50; 95% CI, 1.29-1.73 vs OR, 1.28; 95% CI, 1.22-1.35; P = .05). There was no significant difference in a composite measure of the 6 CMS rewarded therapies between the 2 hospital groups (change in odds per half-year period of receiving CMS therapies: OR, 1.23; 95% CI, 1.15-1.30 vs OR, 1.17; 95% CI, 1.14-1.20; P = .16). For composite measures of acute myocardial infarction treatments not subject to incentives, rates of improvement were not significantly different (OR, 1.09; 95% CI, 1.05-1.14 vs OR, 1.08; 95% CI, 1.06-1.09; P = .49). Overall, there was no evidence that improvements in in-hospital mortality were incrementally greater at pay-for-performance sites (change in odds of in-hospital death per half-year period, 0.91; 95% CI, 0.84-0.99 vs 0.97; 95% CI, 0.94-0.99; P = .21).Conclusions: Among hospitals participating in a voluntary quality-improvement initiative, the pay-for-performance program was not associated with a significant incremental improvement in quality of care or outcomes for acute myocardial infarction. Conversely, we did not find evidence that pay for performance had an adverse association with improvement in processes of care that were not subject to financial incentives. Additional studies of pay for performance are needed to determine its optimal role in quality-improvement initiatives. [ABSTRACT FROM AUTHOR]

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 younger than 65 years of age and Medicare patients 65 years of age or older with patients of similar age who have health maintenance organization (HMO) or private insurance coverage.Setting: 521 U.S. hospitals participating in the CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress ADverse Outcomes with Early Implementation of the ACC [American College of Cardiology]/AHA [American Heart Association] Guidelines) quality improvement initiative from January 2001 through March 2005.Patients: 37,345 NSTE ACS patients younger than 65 years of age and 59,550 patients 65 years of age or older.Measurements: Guideline-recommended treatments, and in-hospital outcomes.Results: Medicaid was the primary payer for 18.7% (6999 of 37,345) of patients younger than age 65 years, whereas Medicare was the primary payer for 67.5% (40,199 of 59,550) of patients age 65 years or older. Medicaid patients were statistically significantly less likely to receive short-term (less than 24 hours) medications and to undergo invasive cardiac procedures than patients covered by HMO and private insurance. They also had higher mortality rates (2.9% vs. 1.2%; adjusted odds ratio, 1.33; 95% CI, 1.08 to 1.63). Medications and invasive procedures were used to a similar extent in patients with Medicare and HMO or private insurance, and respective mortality rates were not significantly different (6.2% vs. 5.6%; adjusted odds ratio, 1.08; 95% CI, 0.99 to 1.18).Limitations: Self-pay patients and patients without insurance were not assessed.Conclusions: NSTE ACS patients with Medicaid (but not Medicare) as the primary payer were less likely to receive evidence-based therapies and had worse outcomes than patients with HMO or private insurance as the primary payer. The causes of these treatment differences and solutions for narrowing the gaps in quality require further investigation. [ABSTRACT FROM AUTHOR]

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 within hospitals). However, these models are computer-intensive and complicated to perform. There is virtually nothing in the literature that compares the results of standard logistic regression to those of hierarchical logistic models in predicting future provider performance.Objective: We sought to compare the ability of standard logistic regression relative to hierarchical modeling in predicting risk-adjusted hospital mortality rates for coronary artery bypass graft (CABG) surgery in New York State.Design, Setting and Patients: New York State CABG Registry data from 1994 to 1999 were used to relate statistical predictions from a given year to hospital performance 2 years hence.Main Outcome Measures: Predicted and observed hospital mortality rates 2 years hence were compared using root mean square errors, the mean absolute difference, and the number of hospitals whose predicted mortality rate data was within a 95% confidence interval around the observed mortality rate.Results: In these data, standard logistic regression performed similarly to hierarchical models, both with and without a second level covariate. Differences in the criteria used for comparison were minimal, and when the differences could be statistically tested no significant differences were identified.Conclusions: It is instructive to compare the predictive abilities of alternative statistical models in the process of assessing their relative performance on a specific database and application. [ABSTRACT FROM AUTHOR]

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. In a large database of patients with known CAD, we (1) explored trends in the use of aspirin over time, (2) characterized patients most likely to take aspirin regularly, and (3) estimated the effectiveness of aspirin use by examining long-term outcomes. Using patients entered in the Duke Databank for Cardiovascular Diseases, we explored the use of aspirin from 1969 to 1999. More than 25,000 patients were sent a questionnaire that included several questions about medication use, including 1 question specifically about aspirin. Patients who failed to respond to the questionnaire received a follow-up telephone call. Aspirin use increased substantially over the most recent 4 years in the study, from 59% in 1995 to 81% in 1999. Predictors of aspirin use included younger age, male sex, being a nonsmoker, and having had a myocardial infarction or revascularization procedure. Patients who never took aspirin had a risk ratio for death of 1.85 compared with patients who regularly took aspirin. Despite the well-known beneficial effects of aspirin, too many patients without contraindications to aspirin fail to take it regularly. The health care system currently lacks effective methods to ensure that patients who have CAD have adequate follow-up concerning aspirin use. [ABSTRACT FROM AUTHOR]

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 population with CAD. The goal was to identify an approach to increase the use of antiplatelet agents by such patients. We surveyed a subset (n = 2,694) of a large CAD referral population (n = 16,174) to determine the use of aspirin and factors associated with its use or nonuse. The subset was made up of all of the CAD referral population who were considered nonusers of aspirin and a 5% sample of those considered aspirin users. We then extrapolated survey data to the overall population to estimate how many eligible patients were not taking antiplatelet agents. In all, 1,626 (63%) of the surviving patients responded to the survey. Of these, 948 (58%) reported taking aspirin, and 678 (42%) reported no aspirin use. The extrapolated rate of aspirin use in the overall population was 85%. Of 2,367 nonusers, 998 (42%, or 6% of the overall cohort) were eligible for antiplatelet agents but were not taking such therapy. Although the rate of aspirin use in this population was higher than previously reported, an estimated 6% of eligible patients were not receiving antiplatelet therapy. [ABSTRACT FROM AUTHOR]

With heighted interest in causal inference based on real-world evidence, this empirical study sought to understand differences between the results of observational analyses and long-term randomized clinical trials. We hypothesized that patients deemed "eligible" for clinical trials would follow a different survival trajectory from those deemed "ineligible" and that this factor could partially explain results. In a large observational registry dataset, we estimated separate survival trajectories for hypothetically trial-eligible vs ineligible patients under both coronary artery bypass surgery (CABG) and percutaneous coronary intervention (PCI). We also explored whether results would depend on the causal inference method (inverse probability of treatment weighting vs optimal full propensity matching) or the approach to combine propensity scores from multiple imputations (the "across" vs "within" approaches). We found that, in this registry population of PCI/CABG multivessel patients, 32.5% would have been eligible for contemporaneous RCTs, suggesting that RCTs enroll selected populations. Additionally, we found treatment selection bias with different distributions of propensity scores between PCI and CABG patients. The different methodological approaches did not result in different conclusions. Overall, trial-eligible patients appeared to demonstrate at least marginally better survival than ineligible patients. Treatment comparisons by eligibility depended on disease severity. Among trial-eligible three-vessel diseased and trial-ineligible two-vessel diseased patients, CABG appeared to have at least a slight advantage with no treatment difference otherwise. In conclusion, our analyses suggest that RCTs enroll highly selected populations, and our findings are generally consistent with RCTs but less pronounced than major registry findings., (© 2020 John Wiley & Sons, Ltd.)

Group-randomized trials are randomized studies that allocate intact groups of individuals to different comparison arms. A frequent practical limitation to adopting such research designs is that only a limited number of groups may be available, and therefore, simple randomization is unable to adequately balance multiple group-level covariates between arms. Therefore, covariate-based constrained randomization was proposed as an allocation technique to achieve balance. Constrained randomization involves generating a large number of possible allocation schemes, calculating a balance score that assesses covariate imbalance, limiting the randomization space to a prespecified percentage of candidate allocations, and randomly selecting one scheme to implement. When the outcome is binary, a number of statistical issues arise regarding the potential advantages of such designs in making inference. In particular, properties found for continuous outcomes may not directly apply, and additional variations on statistical tests are available. Motivated by two recent trials, we conduct a series of Monte Carlo simulations to evaluate the statistical properties of model-based and randomization-based tests under both simple and constrained randomization designs, with varying degrees of analysis-based covariate adjustment. Our results indicate that constrained randomization improves the power of the linearization F-test, the KC-corrected GEE t-test (Kauermann and Carroll, 2001, Journal of the American Statistical Association 96, 1387-1396), and two permutation tests when the prognostic group-level variables are controlled for in the analysis and the size of randomization space is reasonably small. We also demonstrate that constrained randomization reduces power loss from redundant analysis-based adjustment for non-prognostic covariates. Design considerations such as the choice of the balance metric and the size of randomization space are discussed., (Copyright © 2017 John Wiley & Sons, Ltd.)

In group-randomized trials, a frequent practical limitation to adopting rigorous research designs is that only a small number of groups may be available, and therefore, simple randomization cannot be relied upon to balance key group-level prognostic factors across the comparison arms. Constrained randomization is an allocation technique proposed for ensuring balance and can be used together with a permutation test for randomization-based inference. However, several statistical issues have not been thoroughly studied when constrained randomization is considered. Therefore, we used simulations to evaluate key issues including the following: the impact of the choice of the candidate set size and the balance metric used to guide randomization; the choice of adjusted versus unadjusted analysis; and the use of model-based versus randomization-based tests. We conducted a simulation study to compare the type I error and power of the F-test and the permutation test in the presence of group-level potential confounders. Our results indicate that the adjusted F-test and the permutation test perform similarly and slightly better for constrained randomization relative to simple randomization in terms of power, and the candidate set size does not substantially affect their power. Under constrained randomization, however, the unadjusted F-test is conservative, while the unadjusted permutation test carries the desired type I error rate as long as the candidate set size is not too small; the unadjusted permutation test is consistently more powerful than the unadjusted F-test and gains power as candidate set size changes. Finally, we caution against the inappropriate specification of permutation distribution under constrained randomization. An ongoing group-randomized trial is used as an illustrative example for the constrained randomization design., (Copyright © 2015 John Wiley & Sons, Ltd.)

Objectives: We sought to create contemporary models for predicting mortality risk following percutaneous coronary intervention (PCI)., Background: There is a need to identify PCI risk factors and accurately quantify procedural risks to facilitate comparative effectiveness research, provider comparisons, and informed patient decision making., Methods: Data from 181,775 procedures performed from January 2004 to March 2006 were used to develop risk models based on pre-procedural and/or angiographic factors using logistic regression. These models were independently evaluated in 2 validation cohorts: contemporary (n = 121,183, January 2004 to March 2006) and prospective (n = 285,440, March 2006 to March 2007)., Results: Overall, PCI in-hospital mortality was 1.27%, ranging from 0.65% in elective PCI to 4.81% in ST-segment elevation myocardial infarction patients. Multiple pre-procedural clinical factors were significantly associated with in-hospital mortality. Angiographic variables provided only modest incremental information to pre-procedural risk assessments. The overall National Cardiovascular Data Registry (NCDR) model, as well as a simplified NCDR risk score (based on 8 key pre-procedure factors), had excellent discrimination (c-index: 0.93 and 0.91, respectively). Discrimination and calibration of both risk tools were retained among specific patient subgroups, in the validation samples, and when used to estimate 30-day mortality rates among Medicare patients., Conclusions: Risks for early mortality following PCI can be accurately predicted in contemporary practice. Incorporation of such risk tools should facilitate research, clinical decisions, and policy applications., (Copyright 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Results from the Superior Yield of the New Strategy of Enoxaparin, Revascularization, and Glycoprotein IIb/IIIa Inhibitors (SYNERGY) trial showed that the low-molecular-weight heparin (LMWH) enoxaparin was non-inferior compared with unfractionated heparin (UFH) in patients with non-ST-elevation acute coronary syndromes (NSTE-ACS) managed invasively., Hypothesis: We explored the influence of SYNERGY trial site participation on subsequent patterns of heparin use for NSTE-ACS patients treated in routine practice., Methods: We examined temporal patterns of LMWH use compared with UFH use among 122 764 patients with NSTE-ACS enrolled in the Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the ACC/AHA Guidelines (CRUSADE) quality improvement initiative between January 1, 2002 and June 30, 2006, to determine whether site participation in SYNERGY influenced the type of heparin used before and after publication of the SYNERGY results in July 2004., Results: A total of 118 out of 388 (30%) U.S. hospitals participating in CRUSADE simultaneously participated in SYNERGY. SYNERGY sites in the CRUSADE registry were more likely to have a teaching affiliation and have more hospital beds than non-SYNERGY centers in the registry. There was no difference in the proportion of patients treated with LMWH at SYNERGY and non-SYNERGY sites prior to July 2004 compared with after July 2004. However, at SYNERGY sites, there was a slight decrease in the proportion of patients treated with both UFH and LMWH within 24 hours of presentation., Conclusions: The results of the SYNERGY trial did not appear to influence temporal patterns of LMWH use at sites in the CRUSADE registry. Furthermore, site participation in the SYNERGY trial did not alter patterns of LMWH use for NSTE-ACS after publication of the trial results in July 2004., (Copyright (c) 2009 Wiley Periodicals, Inc.)

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-segment elevation ACS in the Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the American College of Cardiology/American Heart Association Guidelines registry., Methods: We examined the association between a history of hypercholesterolemia and in-hospital mortality after adjusting for clinical covariates. After excluding patients with previously diagnosed hypercholesterolemia, we repeated the analysis, examining the association between newly diagnosed hypercholesterolemia (in-hospital low-density lipoprotein cholesterol [LDL-C] > or = 100 mg/dL) and mortality., Results: A history of hypercholesterolemia was associated with lower in-hospital mortality (unadjusted odds ratio [OR]: 0.58; 95% confidence interval [CI]: 0.55, 0.62). This protective association persisted after adjusting for baseline characteristics (OR: 0.71; 95% CI: 0.66, 0.76) and prior statin use (OR: 0.74; 95% CI: 0.68, 0.80). Among 22,711 patients with no history of hypercholesterolemia, 12,809 had a new in-hospital diagnosis of hypercholesterolemia. Unadjusted mortality in these patients was lower than among those with normal LDL levels (OR: 0.58; 95% CI: 0.50, 0.67); however, this difference was not significant after multivariable adjustment (OR: 0.86; 95% CI: 0.73, 1.01)., Conclusions: The association of hypercholesterolemia with better outcomes highlights a major challenge in observational analyses. Our results suggest this paradox may result from confounding due to other clinical characteristics, impact of statin treatment, and perhaps most importantly, the fact that previously diagnosed hypercholesterolemia is a marker for patients with more prior medical contact., (Copyright 2009 Wiley Periodicals, Inc.)

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 included 6218 patients with significant CAD undergoing cardiac catheterization at Duke University between 1996 and 2001, with follow-up through 2002. We investigated the influence of CKD (creatinine clearance < 60 mL/min) upon 3-year survival and medical costs in our CAD population. Coronary artery bypass graft (CABG) surgery was an economically attractive alternative vs. percutaneous coronary intervention (PCI) or medical therapy for all patients with left main disease, three-vessel CAD patients without CKD, and two-vessel CAD patients with CKD. Medical therapy was an economically attractive strategy vs. CABG surgery or PCI for three-vessel CAD patients with CKD, two-vessel CAD patients without CKD, and all single-vessel CAD patients.

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 patients who had surgery between 1994 and 1997 using operative mortality as the only endpoint. Furthermore, this model did not specifically consider mitral valve repair plus CABG, an increasingly common procedure. Consistent with STS policy of periodically updating and improving its risk models, new models for valve surgery combined with CABG have been developed. These models specifically address both perioperative morbidity and mitral valve repair, and they are based on contemporary data., Methods: The final study population consisted of 101,661 procedures, including aortic valve replacement (AVR) plus CABG, mitral valve replacement (MVR) plus CABG, or mitral valve repair (MVRepair) plus CABG between January 1, 2002, and December 31, 2006. Model outcomes included operative mortality, stroke, deep sternal wound infection, reoperation, prolonged ventilation, renal failure, composite major morbidity or mortality, prolonged postoperative length of stay, and short postoperative length of stay. Candidate variables were screened for frequency of missing data, and imputation techniques were used where appropriate. Stepwise variable selection was employed, supplemented by advice from an expert panel of cardiac surgeons and biostatisticians. Several variables were forced into models to insure face validity (eg, atrial fibrillation for the permanent stroke model, sex for all models). Based on preliminary analyses of the data, a single model was employed for valve plus CABG, with indicator variables for the specific type of procedure. Interaction terms were included to allow for differential impact of predictor variables depending on procedure type. After validating the model in the 40% validation sample, the development and validation samples were then combined, and the final model coefficients were estimated using the overall 100% combined sample. The final logistic regression model was estimated using generalized estimating equations to account for clustering of patients within institutions., Results: The c-index for mortality prediction for the overall valve plus CABG population was 0.75. Morbidity model c-indices for specific complications (permanent stroke, renal failure, prolonged ventilation > 24 hours, deep sternal wound infection, reoperation for any reason, major morbidity or mortality composite, and prolonged postoperative length of stay) for the overall group of valve plus CABG procedures ranged from 0.622 to 0.724, and calibration was excellent., Conclusions: New STS risk models have been developed for heart valve surgery combined with CABG. These are the first valve plus CABG models that also include risk prediction for individual major morbidities, composite major morbidity or mortality, and short and prolonged length of stay.

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, and overall outcomes have consistently improved. To adjust for these and other changes, all STS risk models have undergone periodic revisions. This report provides a detailed description of the 2008 STS risk model for coronary artery bypass grafting surgery (CABG)., Methods: The study population consisted of 774,881 isolated CABG procedures performed on adult patients aged 20 to 100 years between January 1, 2002, and December 31, 2006, at 819 STS NCD participating centers. This cohort was randomly divided into a 60% training (development) sample and a 40% test (validation) sample. The development sample was used to identify predictor variables and estimate model coefficients. The validation sample was used to assess model calibration and discrimination. Model outcomes included operative mortality, renal failure, stroke, reoperation for any cause, prolonged ventilation, deep sternal wound infection, composite major morbidity or mortality, prolonged length of stay (> 14 days), and short length of stay (< 6 days and alive). Candidate predictor variables were selected based on their availability in versions 2.35, 2.41, and 2.52.1 of the STS NCD and their presence in (or ability to be mapped to) version 2.61. Potential predictor variables were screened for overall prevalence in the study population, missing data frequency, coding concerns, bivariate relationships with outcomes, and their presence in previous STS or other CABG risk models. Supervised backwards selection was then performed with input from an expert panel of cardiac surgeons and biostatisticians. After successfully validating the fit of the models, the development and validation samples were subsequently combined, and the final regression coefficients were estimated using the overall combined (development plus validation) sample., Results: The c-index for the mortality model was 0.812, and the c-indices for other endpoints ranged from 0.653 for reoperation to 0.793 for renal failure in the validation sample. Plots of observed versus predicted event rates revealed acceptable calibration in the overall population and in numerous subgroups. When patients were grouped into categories of predicted risk, the absolute difference between the observed and expected event rates was less than 1.5% for each endpoint. The final model intercept and coefficients are provided., Conclusions: New STS risk models have been developed for CABG mortality and eight other endpoints. Detailed descriptions of model development and testing are provided, together with the final algorithm. Overall model performance is excellent.

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 outcomes. The Society of Thoracic Surgeons (STS) uses such risk models to create risk-adjusted performance reports for participants in the STS National Adult Cardiac Surgery Database (NCD). Although risk models were initially developed for coronary artery bypass surgery, similar models have now been developed for use with heart valve surgery, particularly as the proportion of such procedures has increased. The last published STS model for isolated valve surgery was based on data from 1994 to 1997 and did not include patients undergoing mitral valve repair. STS has developed new valve surgery models using contemporary data that include both valve repair as well as replacement. Expanding upon existing valve models, the new STS models include several nonfatal complications in addition to mortality., Methods: Using STS data from 2002 to 2006, isolated valve surgery risk models were developed for operative mortality, permanent stroke, renal failure, prolonged ventilation (> 24 hours), deep sternal wound infection, reoperation for any reason, a major morbidity or mortality composite endpoint, prolonged postoperative length of stay, and short postoperative length of stay. The study population consisted of adult patients who underwent one of three types of valve surgery: isolated aortic valve replacement (n = 67,292), isolated mitral valve replacement (n = 21,229), or isolated mitral valve repair (n = 21,238). The population was divided into a 60% development sample and a 40% validation sample. After an initial empirical investigation, the three surgery groups were combined into a single logistic regression model with numerous interactions to allow the covariate effects to differ across these groups. Variables were selected based on a combination of automated stepwise selection and expert panel review., Results: Unadjusted operative mortality (in-hospital regardless of timing, and 30-day regardless of venue) for all isolated valve procedures was 3.4%, and unadjusted in-hospital morbidity rates ranged from 0.3% for deep sternal wound infection to 11.8% for prolonged ventilation. The number of predictors in each model ranged from 10 covariates in the sternal infection model to 24 covariates in the composite mortality plus morbidity model. Discrimination as measured by the c-index ranged from 0.639 for reoperation to 0.799 for mortality. When patients in the validation sample were grouped into 10 categories based on deciles of predicted risk, the average absolute difference between observed versus predicted events within these groups ranged from 0.06% for deep sternal wound infection to 1.06% for prolonged postoperative stay., Conclusions: The new STS risk models for valve surgery include mitral valve repair as well as multiple endpoints other than mortality. Model coefficients are provided and an online risk calculator is publicly available from The Society of Thoracic Surgeons website.

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 features were embedded in a randomized, factorial design in which interventions to improve blood pressure control were delivered to both patients and providers. We examine the effect of the intervention and compare methods of estimation of both fixed effects and variance components in the multilevel generalized linear mixed model. Methods of comparison include penalized quasi-likelihood (PQL), adaptive quadrature, and Bayesian Monte Carlo methods. We also investigate the implications of reducing the data and analysis to baseline and final measurements. In the full analysis, the PQL fixed-effects estimates were closest to zero and confidence intervals were generally narrower than those of the other methods. The adaptive quadrature and Bayesian fixed-effects estimates were similar, but the Bayesian credible intervals were consistently wider. Variance component estimation was markedly different across methods, particularly for the patient-level random effects. In the baseline and final measurement analysis, we found that estimates and corresponding confidence intervals for the adaptive quadrature and Bayesian methods were very similar. However, the time effect was diminished and other factors also failed to reach statistical significance, most likely due to decreased power. When analyzing data from this type of design, we recommend using either adaptive quadrature or Bayesian methods to fit a multilevel generalized linear mixed model including all available measurements.

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 interhospital transfer is necessary to provide rapid access to revascularization procedures for patients who present to community hospitals without revascularization capabilities., Methods: We analyzed patterns and factors associated with interhospital transfer among 19,238 patients with NSTE ACS (positive cardiac markers and/or ischemic ST-segment changes) from 124 community hospitals without revascularization capabilities in the Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA Guidelines quality improvement initiative from January 2001 through June 2004., Results: Less than half of the patients (46.3%) admitted to community hospitals were transferred to tertiary hospitals, and fewer (20%) were transferred early (within 48 hours of presentation). Early transfer rates increased by 16% over 10 quarters in patients with a predicted low or moderate risk of inhospital mortality, compared with 5% in high-risk patients. By the last quarter of the analysis, 41.4% of low-risk patients were transferred early versus 12.5% of high-risk patients. Factors significantly associated with early transfer included younger age, lack of prior heart failure, cardiology inpatient care, and ischemic ST-segment electrocardiographic changes. Among patients who were not transferred, 29% had no further risk stratification performed with stress testing, ejection fraction measurement, or diagnostic cardiac catheterization (at hospitals with catheterization laboratories)., Conclusions: Most patients with NSTE ACS presenting to community hospitals without revascularization capabilities are not rapidly transferred to tertiary hospitals, and lower-risk patients appear to be preferentially transferred early. Further investigation is needed to determine if improved risk-based triage at community hospitals can optimize transfer decision making for high-risk patients with NSTE ACS.

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 performance for 8 publicly reported process measures for acute myocardial infarction (AMI) from 3761 US hospitals during the reporting period of January to December 2005. For each performance measure, we examined the association between hospital case volume, process performance, and designation as a "top hospital" (performance at or above the 90% percentile score)., Results: Sample sizes available for process performance assessment varied considerably, ranging from a median of 3 patients per hospital for timely administration of thrombolytics therapy to 62 patients for aspirin given on arrival at the hospital. In aggregate, hospitals with larger AMI case volumes had better process performance; for example, use of beta-blockers at arrival rose from 72% of patients at hospitals with less than 10 AMI cases to 80% of patients at hospitals with more than 100 cases (P < .001 for volume trend). In contrast, owing to an artifact of wide sampling variation in sites with small denominators, classification of a center as a top hospital actually declined rapidly with increasing case volume using current analytic methods (P < .001). This unexpected association persisted after excluding very low volume centers (<25 cases) and when using Achievable Benchmarks of Care. Using hierarchical models removed the paradoxical association but may have introduced a bias in the opposite direction., Conclusions: Large-volume hospitals had better aggregate performance but were less likely to be identified as top hospitals. Methods that account for small and unequal denominators are needed when assessing hospital process measure performance.

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 Demonstration (HQID) project bases financial rewards and penalties on these scores. Although the HQID composite calculation is straightforward and easily understood, its method of combining process and outcome measures has not been validated., Methods and Results: Using data on 530 hospitals from the Society of Thoracic Surgeons National Cardiac Database, we replicated the HQID methodology with 6 nationally endorsed performance measures (5 process measures plus survival) for coronary artery bypass surgery. Composite scores were essentially determined by process measure performance alone; the survival component explained only 4% of the composite score's total variance. This result persisted even when the survival component was allowed a 5-fold greater weighting in the composite summary. The popular "all-or-none" measurement approach was also dominated by the process component. Substantial disagreement was found among hospital rankings when several alternative methods were used; up to 60% of hospitals eligible for the top financial reward under HQID would change designation depending on the composite methodology used. The application of a simple statistical adjustment (standardization) to each method would provide more consistent results and a more balanced assessment of performance based on both process and outcomes., Conclusions: Existing methods used to create composite performance measures have remarkably different weighting of process versus outcomes metrics and lead to highly divergent provider rankings. Simple alternative methods can create more balanced process-outcome performance assessments.

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 examined the effect of early discharge after CABG on readmission/death and cost within 60 days of discharge home. Variability in hospitals' tendencies for early discharge and adverse outcomes was also explored., Methods: Analyses were based on clinical and claims data for 55,889 New York CABG patients discharged home 1995 to 1998. Early discharge was defined as a postoperative stay below the 15th percentile for patients with similar risk. The likelihood of early discharge and its effect on readmission/death were examined using hierarchical logistic regression, accounting for patient risk and within-hospital correlation. The correlation between early discharge and adverse outcomes at the hospital level was assessed. The effect of early discharge on subsequent inpatient, outpatient, skilled nursing, and home health costs was examined in the Medicare subset., Results: Overall, 17% of patients were discharged early, with increasing prevalence over time. The tendency to discharge early varied widely among hospitals (2% to 42% of patients). We found no association between hospitals' tendencies for early discharge and adverse outcomes. Lower postdischarge costs among patients discharged early (mean = 3,491 dollars versus 5,246 dollars for typical stays) resulted in average cumulative savings of 6,309 dollars., Conclusions: Patients selected for earlier discharge after CABG did not have increased adverse event rates or higher costs. Variation among hospitals in early discharge suggests that more efficient patient management could be achieved at some hospitals.

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. This study examined trends in postoperative LOS, associated rates of transfer at discharge and variation among hospitals in LOS at CABG hospitals in New York State., Methods: Trends in postoperative LOS and transfers at discharge for 105,842 CABG patients treated in 30 hospitals in New York between 1992 and 1998 were first described graphically. Mixed models were then used to assess temporal trends and interhospital variability in LOS, accounting for differences in patient risk and within-hospital correlation in outcomes. Clinical and LOS data were obtained from the Cardiac Surgery Reporting System. Additional information was extracted from the New York Statewide Planning and Research Cooperative System., Results: Postoperative LOS decreased 30% between 1992 and 1998 after adjusting for patient risk. A concurrent increase in the probability of nonacute patient transfers occurred over time, with the most pronounced increase in patients with stays exceeding 5 days. Underlying the downward trend in LOS was substantial interhospital variability that peaked in 1994 and remained significant in 1998. Stays were longer at hospitals located in New York City., Conclusions: The downward shift in LOS observed in the 1990s was achieved in part by an increase in nonacute care transfers, reflecting a shift in care setting. After decreasing trends in postoperative stays tapered off, significant variability among hospitals remained.

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 patients with significant (>75% stenosis) CAD treated at a single center between 1986 and 2000 were assigned to one of three groups based on initial treatment strategy: medical therapy (MED) (n = 6862), PCI (n = 6292), or CABG (n = 5327). Each group was categorized into 3 groups according to baseline severity of CAD: low-severity (predominantly 1-vessel), intermediate-severity (predominantly 2-vessel), and high-severity (all 3-vessel), and prospectively evaluated in Cox models for all-cause mortality adjusted for cardiac risk, comorbidity, and propensity for selection of a specific treatment. Treatments were compared for the entire period and three eras (1: 1986 to 1990; 2: 1991 to 1995; 3: 1996 to 2000), the last encompassing widespread availability of PCI with stenting., Results: Survival significantly improved in all groups for all degrees of CAD, despite increasing severity of illness. Revascularization strategies provided significant survival over MED with 8.1, 10.6, and 23.6 additional months per 15 years of follow-up for low-severity, intermediate-severity, and high-severity CAD, respectively. Therapeutic improvements led to increased survival of 5.3 additional months per 7 years of follow-up (95% confidence interval, 0.2 to 10.2; p = 0.039) in era 3 for CABG compared with PCI for high-severity CAD., Conclusions: Initial revascularization strategies result in significant survival advantage over MED for all CAD levels. Patients with high-severity CAD have reduced survival with PCI compared with those initially treated with CABG.

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 the Duke Databank for Cardiovascular Disease (DDCD) were identified for a prospective, randomized study using a multifaceted intervention to improve beta-blocker use. Intervention practices received provider education, patient education materials, feedback on beta-blocker use of their patients with HF, and access to telephone consultation with an HF expert. The primary outcome was a comparison between intervention and control practices of the proportion of patients with HF self-reporting beta-blocker use on their first routine DDCD follow-up in the postintervention year. A random effects model was used for the analysis., Results: Post intervention, 2631 patients (1701 in 23 intervention practices and 930 in 22 control practices) completed DDCD follow-up. No significant difference in the proportion of patients with HF reporting beta-blocker use was found in the intervention versus control groups (OR 1.16, 95% CI 0.94-1.43, P = .2), although more patients in the intervention group started a beta-blocker than stopped a beta-blocker during the study period (P = .02)., Conclusions: This multifaceted intervention did not significantly increase the mean proportion of patients taking beta-blockers within practices exposed to the intervention, although favorable trends were observed. Further studies are needed to identify and evaluate strategies for translating evidence into clinical practice to reduce the global health burden associated with HF.

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 with the American College of Cardiology/American Heart Association (ACC/AHA) guideline recommendations, to examine how hospital performance varied among centers, to identify characteristics predictive of higher guideline adherence, and to assess whether hospitals' overall composite guideline adherence was associated with observed and risk-adjusted in-hospital mortality rates., Design, Setting, and Participants: An observational analysis of hospital care in 350 academic and nonacademic US centers of 64,775 patients enrolled in the CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the ACC/AHA Guidelines) National Quality Improvement Initiative between January 1, 2001, and September 30, 2003, presenting with chest pain and positive electrocardiographic changes or cardiac biomarkers consistent with non-ST-segment elevation acute coronary syndrome (ACS)., Main Outcome Measures: Use of 9 ACC/AHA class I guideline-recommended treatments and the correlation among hospitals' use of individual care processes as well as overall composite adherence rates., Results: Overall, the 9 ACC/AHA guideline-recommended treatments were adhered to in 74% of eligible instances. There was modest correlation in hospital performance among the individual ACS process metrics. However, composite adherence performance varied widely (median [interquartile range] composite adherence scores from lowest to highest hospital quartiles, 63% [59%-66%] vs 82% [80%-84%]). Composite guideline adherence rate was significantly associated with in-hospital mortality, with observed mortality rates decreasing from 6.31% for the lowest adherence quartile to 4.15% for the highest adherence quartile (P<.001). After risk adjustment, every 10% increase in composite adherence at a hospital was associated with an analogous 10% decrease in its patients' likelihood of in-hospital mortality (adjusted odds ratio, 0.90; 95% confidence interval, 0.84-0.97; P<.001)., Conclusion: A significant association between care process and outcomes was found, supporting the use of broad, guideline-based performance metrics as a means of assessing and helping improve hospital quality.

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 factors for operative mortality comprehensively across the entire spectrum of cardiac valvular procedures over the past decade., Methods: All 409,904 valve procedures in the Society of Thoracic Surgeons database performed between 1994 and 2003 were assessed, and Society of Thoracic Surgeons preoperative and operative variables were related to operative mortality by using a multivariable logistic regression model. Data were greater than 95% complete, and the relative importance of relevant risk factors was determined by ranking odds ratios. The analysis had a high predictive power, with a C statistic of 0.735., Results: In the model, 19 variables independently influenced operative mortality (all P < .01). The most significant was nonelective (acute) presentation (odds ratios, 2.11), followed by advanced age (odds ratios, 1.88), reoperation (odds ratios, 1.61), endocarditis (odds ratios, 1.59), and coronary disease (odds ratios, 1.58). Generally, valve replacement was associated with higher mortality than repair (odds ratios, 1.52). Overall, female gender was very important (odds ratios, 1.37), and earlier year of operation increased risk (odds ratios, 1.34), implying improving outcomes over time. Although any single comorbidity, on average, was only moderately contributory (odds ratios, 1.19), specific comorbidities, such as renal failure, or multiple comorbidities in a given patient could be very significant. Aortic root reconstruction carried the highest risk (odds ratios, 2.78), followed by tricuspid valve surgery (odds ratios, 2.26), multiple valve procedures (odds ratios, 2.06), and then isolated mitral (odds ratios, 1.47), pulmonic (odds ratios, 1.29), and aortic (reference procedure) operations. Reduced ejection fraction and severity of valve lesion were relatively less important (odds ratios, 1.34 and 0.83, respectively)., Conclusions: These data illustrate the significance of acute presentation in determining operative risk, and earlier surgical intervention under elective conditions might be emphasized for all types of significant valve lesions. Because aortic root reconstruction doubles mortality compared with simple aortic valve procedures, root replacement should be reserved for specific root pathology. Finally, issues related to reoperation, endocarditis, valve repair, gender, and the various procedures deserve more detailed examination.

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 Background Data: Pheochromocytoma is a rare, catecholamine-producing tumor with preferential localization in the adrenal gland. Despite its importance, the most sensitive test to establish the diagnosis remains to be defined., Methods: Prospective data collection was done on patients with pheochromocytoma treated at the Duke University Medical Center and the Durham Veterans Affairs Medical Center, Durham, NC. All urinary, plasma, and platelet analyses were highly standardized and supervised by one investigator (J.M.F.). I-MIBG scans were independently reviewed by 2 nuclear medicine physicians., Results: A total of 152 patients (55.3% female) were enrolled in the present analysis. Patients were predominantly white (73.7%). Spells (defined as profuse sweating, tachycardia, and headache) and hypertension at diagnosis were present in 51.4% and 66.6%, respectively. Bilateral disease was found in 12.5%, malignant pheochromocytoma in 29.6%, and hereditary forms in 23.0%. The most sensitive tests were total urinary normetanephrine (96.9%), platelet norepinephrine (93.8%), and I-MIBG scintigraphy (83.7%). In combination with I-MIBG scintigraphy, platelet norepinephrine had a sensitivity of 100%, plasma norepinephrine/MIBG of 97.1%, total urine normetanephrine/MIBG of 96.6%, and urine norepinephrine/MIBG of 95.3%., Conclusions: The tests of choice to establish the diagnosis of pheochromocytoma are urinary normetanephrine and platelet norepinephrine. A combination of I-MIBG scintigraphy and diagnostic tests in urine, blood, or platelets does further improve the sensitivity. We thus advocate performing an MIBG scan if the diagnosis of pheochromocytoma is clinically suspected and catecholamine measurements are within the normal range.

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 is frequently assessed from observational data. For evaluating the influence of such medical processes on patient outcomes, not only is risk adjustment an issue, but also the "center effect" represents an important, often overlooked consideration. Both the quality of care and the tendency to use certain treatments or processes vary from one center to another. The induced similarity in outcomes within center, as well as the potential for confounding by center, needs to be addressed within the context of risk adjustment. In addition, center-specific selection criteria for a treatment strategy can vary with respect to patient risk. Because of these considerations, it is important to adequately separate the within-center effects of the treatment or strategy from the across-center effects, which relate more to center performance. The primary objective of this article is to explore and extend current methods of dealing with center confounding for dichotomous outcomes, primarily for the situation where selection on the basis of patient risk can vary from center to center. A simulation study compares results from several different analytic methods and provides evidence for the importance of considering confounding due to both risk and center when evaluating the effectiveness of a process. An example that examines the effect of early extubation after bypass surgery is also presented.

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 among blacks and whites with documented coronary disease and to assess whether differential use of revascularization procedures affects these outcomes., Methods and Results: We identified a prospective cohort of 1534 white and 337 black patients undergoing cardiac catheterization between August 1998 and April 2001. Health status was assessed at baseline and 6 months with the Short-Form 36 (SF-36) Health Survey and the Seattle Angina Questionnaire (SAQ) Angina Frequency Scale. Compared with whites, blacks received fewer coronary revascularization procedures (52.5% versus 66.0%; P<0.01). By 6 months, blacks had similar mortality (odds ratio, 1.03; 95% CI, 0.57 to 1.9) but worse scores in 5 SF-36 domains (physical, social, role physical, role emotional, and mental health function). Blacks also reported higher rates of angina at 6 months than whites (34.2% versus 24.6%; P<0.01). After adjustment for baseline functional status and clinical and demographic variables, blacks had significantly worse summary physical component scores, summary mental component scores, and SAQ Angina Frequency Scale scores. However, differences in physical component summary scores and SAQ scores between blacks and whites were no longer significant after adjustment for revascularization status., Conclusions: Our study is among the first to document greater symptoms and functional impairment among black cardiac patients relative to whites. Differential use of coronary revascularization may contribute to the poorer functional outcomes observed among black patients with documented coronary disease.

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 of 437 neonates developed GNR-b; most commonly with Klebsiella (122/437; 28%), Enterobacter (97/437; 22%), Escherichia coli (90/437; 21%), Pseudomonas (63/437; 14%), and Serratia (49/437; 11%). Neonates infected with Pseudomonas were more likely to die (21/63; 33%) than infants infected with other GNR (50/374; 13%). In multivariable logistic regression, infection with Pseudomonas, mechanical ventilation, and race were associated with subsequent mortality. Postconception age (PCA) was most strongly associated with mortality. Using neonates with >34 weeks PCA at the time of the first blood culture as the reference category, mortality was higher in neonates <26 weeks PCA (odds ratio (OR)=9.21; 95% confidence interval (CI)=2.79, 30.44), and in neonates 26 to 28 weeks PCA (OR=3.94; 95% CI=1.29, 12.03)., Conclusions: Among premature infants, much of the mortality experienced in GNR-b is due to infection with Pseudomonas rather than enteric GNR. Race, the need for mechanical ventilation, and younger PCA when the blood culture was obtained were also strongly associated with mortality.

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 patients may not encourage treatment adoption. We assessed the economic effects of beta-blocker therapy from various perspectives: societal, Medicare, hospital, physician, and patient., Methods: A Markov model of heart failure progression over 5 years was developed. Transition probabilities and the effect of beta-blockers on mortality and hospitalization were based on clinical trial data. Estimates of hospital costs and reimbursement were obtained from the Duke University Medical Center. Physician fees were based on the Medicare fee schedule., Results: Beta-blocker therapy increased survival by 0.3 years per patient and reduced societal costs by US dollars 3959 per patient over 5 years. Medicare costs declined by US dollars 6064 per patient, due primarily to lower hospitalization rates. Unless heart failure admissions could be replaced with other hospitalizations that generated an equal or greater revenue above variable cost, hospital revenue would be negatively affected. Physician revenue from treating heart failure patients would also decline. Patient costs increased with beta-blocker use (US dollars 2113 over 5 years)., Conclusion: Beta-blocker therapy improves the clinical outcomes of heart failure patients and is cost saving to society and Medicare. However, hospitals and physicians have no clear financial incentives to support increased beta-blocker use. Changes in practice patterns could be encouraged by linking reimbursement with evidence-based care and covering patients' medication costs.

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 accepted as a standard quality metric., Objective: To examine the contemporary association between hospital CABG procedure volume and outcome in a large national clinical database., Design, Setting, and Participants: Observational analysis of 267 089 isolated CABG procedures performed at 439 US hospitals participating in the Society of Thoracic Surgeons National Cardiac Database between January 1, 2000, and December 31, 2001., Main Outcome Measure: Association between hospital CABG procedural volume and all-cause operative mortality (in-hospital or 30-day, whichever was longer)., Results: The median (interquartile range) annual hospital-isolated CABG volume was 253 (165-417) procedures, with 82% of centers performing fewer than 500 procedures per year. The overall operative mortality was 2.66%. After adjusting for patient risk and clustering effects, rates of operative mortality decreased with increasing hospital CABG volume (0.07% for every 100 additional CABG procedures; adjusted odds ratio [OR], 0.98; 95% confidence interval [CI], 0.96-0.99; P =.004). While the association between volume and outcome was statistically significant overall, this association was not observed in patients younger than 65 years or in those at low operative risk and was confounded by surgeon volume. The ability of hospital volume to discriminate those centers with significantly better or worse mortality was limited due to the wide variability in risk-adjusted mortality among hospitals with similar volume. Closure of up to 100 of the lowest-volume centers (ie, those performing < or =150 CABG procedures/year) was estimated to avert fewer than 50 of 7110 (<1% of total) CABG-related deaths., Conclusion: In contemporary practice, hospital procedural volume is only modestly associated with CABG outcomes and therefore may not be an adequate quality metric for CABG surgery.

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 construct the ROC curve. We extend the standard method to accommodate a framework in which the diagnostic test is repeated over time to monitor for occurrence of an event. Unlike the usual situation in which event status is static, the problem we address involves event status that is not constant over the monitoring period. Subjects generally are classified as non-events, or controls, until they experience events that convert them to cases. Viewing the data as incomplete discrete failure time data with time-varying covariates, potentially useful diagnostic markers can be related appropriately in time with the true condition and varying amounts of information per individual can be taken into account. The ROC curve provides an assessment of the performance of the test in combination with the schedule of testing. Within this framework, a computational simplification is introduced to calculate variances and covariances for the areas under the ROC curves. Periodic monitoring for reperfusion following thrombolytic treatment for acute myocardial infarction provides a detailed example, whereby the lengths of the testing interval combined with different diagnostic markers are compared., (Copyright 2003 John Wiley & Sons, Ltd.)

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, these do not exist for neonates., Methods: A multicenter, retrospective, cohort study was conducted of neonatal intensive care unit patients (N = 6172) who had a blood culture (N = 21,233) after day of life 3 and whose birth weight was or=28 weeks. We developed a candidemia score on the basis of the ORs from the multivariable model. Children with a candidemia score >or=2 points were classified as having a "positive" score, and a score of >or=2 points had a sensitivity of 85% and a specificity of 47%., Conclusions: We developed a clinical predictive model for neonatal candidemia with high sensitivity and moderate specificity for candidemia. On the basis of our model, when a physician obtains a blood culture, the physician should consider providing antifungal therapy to neonates who are <25 weeks' estimated gestational age and to neonates who have thrombocytopenia at the time of blood culture. In addition, if a physician obtains a blood culture from a child who is 25 to 27 weeks' estimated gestational age and is not thrombocytopenic but has a history of third-generation cephalosporin or carbapenem exposure in the 7 days before the blood culture, then the physician should consider administration of empirical antifungal therapy.

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 artery bypass graft (CABG) surgery process-of-care measures: preoperative beta-blockade therapy and internal mammary artery (IMA) grafting in patients 75 years or older., Design, Setting, and Participants: Three hundred fifty-nine academic and nonacademic hospitals (treating 267 917 patients using CABG surgery) participating in the Society of Thoracic Surgeons National Cardiac Database between January 2000 and July 2002 were randomized to a control arm or to 1 of 2 groups that used CQI interventions designed to increase use of the process-of-care measures., Intervention: Each intervention group received measure-specific information, including a call to action to a physician leader; educational products; and periodic longitudinal, nationally benchmarked, site-specific feedback., Main Outcome Measure: Differential incorporation of the targeted care processes into practice at the intervention sites vs the control sites, assessed by measuring preintervention (January-December 2000)/postintervention (January 2001-July 2002) site differences and by using a hierarchical patient-level analysis., Results: From January 2000 to July 2002, use of both process measures increased nationally (beta-blockade, 60.0%-65.6%; IMA grafting, 76.2%-82.8%). Use of beta-blockade increased significantly more at beta-blockade intervention sites (7.3% [SD, 12.8%]) vs control sites (3.6% [SD, 11.5%]) in the preintervention/postintervention (P =.04) and hierarchical analyses (P<.001). Use of IMA grafting also tended to increase at IMA intervention sites (8.7% [SD, 17.5%]) vs control sites (5.4% [SD,15.8%]) (P =.20 and P =.11 for preintervention/postintervention and hierarchical analyses, respectively). Both interventions tended to have more impact at lower-volume CABG sites (for interaction: P =.04 for beta-blockade; P =.02 for IMA grafting)., Conclusions: A multifaceted, physician-led, low-intensity CQI effort can improve the adoption of care processes into national practice within the context of a medical specialty society infrastructure.