Acute Myocardial Infarction Cohorts Defined by International Classification of Diseases, Tenth Revision Versus Diagnosis-Related Groups: Analysis of Diagnostic Agreement and Quality Measures in an Integrated Health System.

BACKGROUND: Among Medicare value-based payment programs for acute myocardial infarction (AMI), the Hospital Readmissions Reduction Program uses International Classification of Diseases, Tenth Revision (ICD-10) codes to identify the program denominator, while the Bundled Payments for Care Improvement Advanced program uses diagnosis-related groups (DRGs). The extent to which these programs target similar patients, whether they target the intended population (type 1 myocardial infarction), and whether outcomes are comparable between cohorts is not known. METHODS: In a retrospective study of 2176 patients hospitalized in an integrated health system, a cohort of patients assigned a principal ICD-10 diagnosis of AMI and a cohort of patients assigned an AMI DRG were compared according to patient-level agreement and outcomes such as mortality and readmission. RESULTS: One thousand nine hundred thirty-five patients were included in the ICD-10 cohort compared with 662 patients in the DRG cohort. Only 421 patients were included in both AMI cohorts (19.3% agreement). DRG cohort patients were older (70 versus 65 years, P<0.001), more often female (48% versus 30%, P<0.001), and had higher rates of heart failure (52% versus 33%, P<0.001) and kidney disease (42% versus 25%, P<0.001). Comparing outcomes, the DRG cohort had significantly higher unadjusted rates of 30-day mortality (6.6% versus 2.5%, P<0.001), 1-year mortality (21% versus 8%, P<0.001), and 90-day readmission (26% versus 19%, P=0.006) than the ICD-10 cohort. Two observations help explain these differences: 61% of ICD-10 cohort patients were assigned procedural DRGs for revascularization instead of an AMI DRG, and type 1 myocardial infarction patients made up a smaller proportion of the DRG cohort (34%) than the ICD-10 cohort (78%). CONCLUSIONS: The method used to identify denominators for value-based payment programs has important implications for the patient characteristics and outcomes of the populations. As national and local quality initiatives mature, an emphasis on ICD-10 codes to define AMI cohorts would better represent type 1 myocardial infarction patients.

Characteristics, Management, and Outcomes of Patients Hospitalized for Heart Failure in China: The China PEACE Retrospective Heart Failure Study.

Background Heart failure (HF) is an emerging epidemic in China and accounts for significant healthcare resource utilization in the inpatient setting. To create evidence-based, life-saving, and cost-saving hospitalization systems, the first step is to characterize the contemporary national landscape of inpatient HF care. Methods and Results In the China PEACE 5r-HF study (China Patient-centered evaluative Assessment of Cardiac Events Retrospective Study of Heart Failure), we used 2-stage random sampling to create a nationally representative cohort of 10 004 admissions for HF from 189 hospitals in 2015 in China. Data on patient characteristics, management, and outcomes were obtained through centralized medical record abstraction. The median age of the cohort was 73 years (interquartile range, 65-80), and 48.9% were women. More than half (56.2%) of the patients were hospitalized in rural areas. Prevalence of ejection fraction ≥50%, 40% to 50%, and <40% was 60.3%, 17.7%, and 22.0%, respectively. We identified substantial gaps in care, including underutilization of diagnostic tests such as echocardiograms (63.6%), chest imaging (75.2%), and biomarker testing (56.4%), low prescription rates of guideline-recommended medications during hospitalization and at discharge, suboptimal rates of follow-up appointments (24.3%), and widespread utilization of traditional Chinese medicine (74.8%). The combined rate of in-hospital mortality and treatment withdrawal in our study was 3.5%, and median length-of-stay was 9 days (interquartile range, 7-13). Conclusions Patients admitted with acute HF in China have distinctive epidemiology and receive substandard care, but have low inpatient mortality despite long length of stay. These findings provide opportunities for streamlining efficiencies while improving quality of inpatient HF care in China. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT02877914.

Traditional Chinese Medicine Use in the Treatment of Acute Heart Failure in Western Medicine Hospitals in China: Analysis From the China PEACE Retrospective Heart Failure Study.

Background Traditional Chinese medicine (TCM) is used in the treatment of many conditions, including heart failure (HF), although it is not well characterized. Methods and Results We conducted a retrospective analysis of TCM use in a random sample of hospitalizations for HF within a random sample of Western medicine hospitals in China in 2015 using data from the China PEACE 5r-HF (China Patient-Centered Evaluative Assessment of Cardiac Events 5 Retrospective Heart Failure Study). We describe the frequency of TCM use and its association with patient characteristics, in-hospital use of evidence-based therapies, and hospital characteristics using hierarchical logistic regression models. Finally, we assessed risk-adjusted in-hospital bleeding and mortality. Among 10 004 patients hospitalized with HF (median age, 73 years; 48.9% women) from 189 hospitals, 74.7% received TCM (83.3% administered intravenously). The most commonly used agent was Salvia miltiorrhiza (51.2%). Patients with coronary artery disease (odds ratio [OR], 1.73; 95% CI, 1.53-1.95) or stroke (OR, 1.32; 95% CI, 1.15-1.51) were more likely to receive TCM; there was no correlation with evidence-based therapy use. Nearly all hospitals (99.4%) used TCM, with substantial variation across hospitals (median OR, 3.29; 95% CI, 2.82-3.76). In-patient bleeding (OR, 1.39; 95% CI, 1.03-1.88) and mortality (OR, 1.36; 95% CI, 1.04-1.79) were higher with Salvia miltiorrhiza, although not with other TCMs. Conclusions In a nationally representative sample of patients hospitalized with acute HF in China, three fourths received TCM. Nearly all hospitals used TCM, although use varied substantially by hospital. Although TCM was not used in lieu of evidence-based therapies for HF, we found a signal for harm with the most commonly used TCM. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT02877914.

Predicting Length of Stay and the Need for Postacute Care After Acute Myocardial Infarction to Improve Healthcare Efficiency.

Background To improve value in the care of patients with acute myocardial infarction (MI), payment models increasingly hold providers accountable for costs. As such, providers need tools to predict length of stay (LOS) during hospitalization and the likelihood of needing postacute care facilities after discharge for acute MI patients. We developed models to estimate risk for prolonged LOS and postacute care for acute MI patients at time of hospital admission to facilitate coordinated care planning. Methods and Results We identified patients in the National Cardiovascular Data Registry ACTION registry (Acute Coronary Treatment and Intervention Outcomes Network) who were discharged alive after hospitalization for acute MI between July 1, 2008 and March 31, 2017. Within a 70% random sample (Training cohort) we developed hierarchical, proportional odds models to predict LOS and hierarchical logistic regression models to predict discharge to postacute care. Models were validated in the remaining 30%. Of 633 737 patients in the Training cohort, 16.8% had a prolonged LOS (≥7 days) and 7.8% were discharged to a postacute facility (extended care, a transitional care unit, or rehabilitation). Model discrimination was moderate in the validation dataset for predicting LOS (C statistic=0.640) and strong for predicting discharge to postacute care (C statistic=0.827). For both models, discrimination was similar in ST-segment-elevation MI and non-ST-segment-elevation MI subgroups and calibration was excellent. Conclusions These models developed in a national registry can be used at the time of initial hospitalization to predict LOS and discharge to postacute facilities. Prospective testing of these models is needed to establish how they can improve care coordination and lower costs.

Traditional Chinese Medicine for Acute Myocardial Infarction in Western Medicine Hospitals in China.

BACKGROUND: Amid national efforts to improve the quality of care for people with cardiovascular disease in China, the use of traditional Chinese medicine (TCM) is increasing, yet little is known about its use in the early management of acute myocardial infarction (AMI). METHODS AND RESULTS: We aimed to examine intravenous use of TCM within the first 24 hours of hospitalization (early IV TCM) for AMI. Data come from the China Patient-centered Evaluative Assessment of Cardiac Events Retrospective Study of Acute Myocardial Infarction, restricted to a large, representative sample of Western medicine hospitals throughout China (n=162). We conducted a chart review of randomly sampled patients with AMI in 2001, 2006, and 2011, comparing early intravenous TCM use across years, predictors of any early intravenous TCM use, and association with in-hospital bleeding and mortality. From 2001 to 2011, early intravenous TCM use increased (2001: 38.2% versus 2006: 49.1% versus 2011: 56.1%; P<0.01). Nearly all (99%) hospitals used early intravenous TCM. Salvia miltiorrhiza was most commonly prescribed, used in one third (35.5%) of all patients admitted with AMI. Patients receiving any early intravenous TCM, compared with those who did not, were similar in age and sex and had fewer cardiovascular risk factors. In multivariable hierarchical models, admission to a secondary (versus tertiary) hospital was most strongly associated with early intravenous TCM use (odds ratio: 2.85; 95% confidence interval: 1.98-4.11). Hospital-level factors accounted for 55% of the variance (adjusted median odds ratio: 2.84). In exploratory analyses, there were no significant associations between early intravenous TCM and in-hospital bleeding or mortality. CONCLUSIONS: Early intravenous TCM use for AMI in China is increasing despite the lack of evidence of their benefit or harm. There is an urgent need to define the effects of these medications because they have become a staple of treatment in the world's most populous country. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01624883.

Comparison of Inappropriate Shocks and Other Health Outcomes Between Single- and Dual-Chamber Implantable Cardioverter-Defibrillators for Primary Prevention of Sudden Cardiac Death: Results From the Cardiovascular Research Network Longitudinal Study of Implantable Cardioverter-Defibrillators.

BACKGROUND: In US clinical practice, many patients who undergo placement of an implantable cardioverter-defibrillator (ICD) for primary prevention of sudden cardiac death receive dual-chamber devices. The superiority of dual-chamber over single-chamber devices in reducing the risk of inappropriate ICD shocks in clinical practice has not been established. The objective of this study was to compare risk of adverse outcomes, including inappropriate shocks, between single- and dual-chamber ICDs for primary prevention. METHODS AND RESULTS: We identified patients receiving a single- or dual-chamber ICD for primary prevention who did not have an indication for pacing from 15 hospitals within 7 integrated health delivery systems in the Longitudinal Study of Implantable Cardioverter-Defibrillators from 2006 to 2009. The primary outcome was time to first inappropriate shock. ICD shocks were adjudicated for appropriateness. Other outcomes included all-cause hospitalization, heart failure hospitalization, and death. Patient, clinician, and hospital-level factors were accounted for using propensity score weighting methods. Among 1042 patients without pacing indications, 54.0% (n=563) received a single-chamber device and 46.0% (n=479) received a dual-chamber device. In a propensity-weighted analysis, device type was not significantly associated with inappropriate shock (hazard ratio, 0.91; 95% confidence interval, 0.59-1.38 [P=0.65]), all-cause hospitalization (hazard ratio, 1.03; 95% confidence interval, 0.87-1.21 [P=0.76]), heart failure hospitalization (hazard ratio, 0.93; 95% confidence interval, 0.72-1.21 [P=0.59]), or death (hazard ratio, 1.19; 95% confidence interval, 0.93-1.53 [P=0.17]). CONCLUSIONS: Among patients who received an ICD for primary prevention without indications for pacing, dual-chamber devices were not associated with lower risk of inappropriate shock or differences in hospitalization or death compared with single-chamber devices. This study does not justify the use of dual-chamber devices to minimize inappropriate shocks.

Cardiac Stress Test Trends Among US Patients Younger Than 65 Years, 2005-2012.

IMPORTANCE: After a period of rapid growth, use of cardiac stress testing has recently decreased among Medicare beneficiaries and in a large integrated health system. However, it is not known whether declines in cardiac stress testing are universal or are confined to certain populations. OBJECTIVE: To determine trends in rates of cardiac stress testing among a large and diverse cohort of commercially insured patients. DESIGN, SETTING, AND PARTICIPANTS: A serial cross-sectional study with time trends was conducted using administrative claims from all members aged 25 to 64 years belonging to a large, national managed care company from January 1, 2005, to December 31, 2012. Linear trends in rates were determined using negative binomial regression models with procedure count as the dependent variable, calendar quarter as the key independent variable, and the size of the population as a logged offset term. Data analysis was performed from January 1, 2005, to December 31, 2012. MAIN OUTCOMES AND MEASURES: Age- and sex-adjusted rates of cardiac stress tests per calendar quarter (reported as number of tests per 100 000 person-years). RESULTS: A total of 2 085 591 cardiac stress tests were performed among 32 921 838 persons (mean [SD] age, 43.2 [10.9] years; 16 625 528 women [50.5%] and 16 296 310 [49.5%] men; 7 604 945 nonwhite [23.1%]). There was a 3.0% increase in rates of cardiac stress testing from 2005 (3486 tests; 95% CI, 3458-3514) to 2012 (3589 tests; 95% CI, 3559-3619; P = .01 for linear trend). Use of nuclear single-photon emission computed tomography decreased by 14.9% from 2005 (1907 tests; 95% CI, 1888-1926) to 2012 (1623 tests; 95% CI, 1603-1643; P = .03). Use of stress echocardiography increased by 27.8% from 2005 (709 tests; 95% CI, 697-721) to 2012 (906 tests; 95% CI, 894 to 920; P < .001). Use of exercise electrocardiography increased by 12.5% from 2005 (861 tests; 95% CI, 847-873) to 2012 (969 tests; 95% CI, 953-985; P < .001). Use of other stress testing modalities increased 65.5% from 2006 (55 tests; 95% CI, 51-59) to 2012 (91 tests; 95% CI, 87-95; P < .001). For individuals aged 25 to 34 years, rates of cardiac stress testing increased 59.1% from 2005 (543 tests; 95% CI, 532-554) to 2012 (864 tests; 95% CI, 852-876; P < .001). For individuals aged 55 to 64 years, rates of cardiac stress testing decreased by 12.3% from 2005 (7894 tests; 95% CI, 7820-7968) to 2012 (6923 tests; 95% CI, 6853-6993; P < .001). CONCLUSIONS AND RELEVANCE: In contrast to declines in the use of cardiac stress testing in some health care systems, we observed a small increase in its use among a nationally representative cohort of commercially insured patients. Our findings suggest that observed trends in the use of cardiac stress testing may have been driven more by unique characteristics of populations and health systems than national efforts to reduce the overuse of testing.

National Quality Assessment of Early Clopidogrel Therapy in Chinese Patients With Acute Myocardial Infarction (AMI) in 2006 and 2011: Insights From the China Patient-Centered Evaluative Assessment of Cardiac Events (PEACE)-Retrospective AMI Study.

BACKGROUND: Early clopidogrel administration to patients with acute myocardial infarction (AMI) has been demonstrated to improve outcomes in a large Chinese trial. However, patterns of use of clopidogrel for patients with AMI in China are unknown. METHODS AND RESULTS: From a nationally representative sample of AMI patients from 2006 and 2011, we identified 11 944 eligible patients for clopidogrel therapy and measured early clopidogrel use, defined as initiation within 24 hours of hospital admission. Among the patients eligible for clopidogrel, the weighted rate of early clopidogrel therapy increased from 45.7% in 2006 to 79.8% in 2011 (P<0.001). In 2006 and 2011, there was significant variation in early clopidogrel use by region, ranging from 1.5% to 58.0% in 2006 (P<0.001) and 48.7% to 87.7% in 2011 (P<0.001). While early use of clopidogrel was uniformly high in urban hospitals in 2011 (median 89.3%; interquartile range: 80.1% to 94.5%), there was marked heterogeneity among rural hospitals (median 50.0%; interquartile range: 11.5% to 84.4%). Patients without reperfusion therapy and those admitted to rural hospitals were less likely to be treated with clopidogrel. CONCLUSIONS: Although the use of early clopidogrel therapy in patients with AMI has increased substantially in China, there is notable wide variation across hospitals, with much less adoption in rural hospitals. Quality improvement initiatives are needed to increase consistency of early clopidogrel use for patients with AMI. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov/. Unique identifier: NCT01624883.

Incidence and prognosis of resistant hypertension in hypertensive patients.

BACKGROUND: Despite a recent American Heart Association (AHA) consensus statement emphasizing the importance of resistant hypertension, the incidence and prognosis of this condition are largely unknown. METHODS AND RESULTS: This retrospective cohort study in 2 integrated health plans included patients with incident hypertension in whom treatment was begun between 2002 and 2006. Patients were followed up for the development of resistant hypertension based on AHA criteria of uncontrolled blood pressure despite use of ≥3 antihypertensive medications, with data collected on prescription filling information and blood pressure measurement. We determined incident cardiovascular events (death or incident myocardial infarction, heart failure, stroke, or chronic kidney disease) in patients with and without resistant hypertension with adjustment for patient and clinical characteristics. Among 205 750 patients with incident hypertension, 1.9% developed resistant hypertension within a median of 1.5 years from initial treatment (0.7 cases per 100 person-years of follow-up). These patients were more often men, were older, and had higher rates of diabetes mellitus than nonresistant patients. Over 3.8 years of median follow-up, cardiovascular event rates were significantly higher in those with resistant hypertension (unadjusted 18.0% versus 13.5%, P<0.001). After adjustment for patient and clinical characteristics, resistant hypertension was associated with a higher risk of cardiovascular events (hazard ratio, 1.47; 95% confidence interval, 1.33-1.62). CONCLUSIONS: Among patients with incident hypertension in whom treatment was begun, 1 in 50 patients developed resistant hypertension. Patients with resistant hypertension had an increased risk of cardiovascular events, which supports the need for greater efforts toward improving hypertension outcomes in this population.

ACCF/AHA methodology for the development of quality measures for cardiovascular technology: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Performance Measures.

Consistent with the growing national focus on healthcare quality, the American College of Cardiology Foundation (ACCF) and the American Heart Association (AHA) have taken a leadership role over the past decade in developing measures of the quality of cardiovascular care by convening a joint ACCF/AHA Task Force on Performance Measures. The Task Force is charged with identifying the clinical topics appropriate for the development of performance measures and with assembling writing committees composed of clinical and methodological experts in collaboration with appropriate subspecialty societies. The Task Force has also created methodology documents that offer guidance in the development of process, outcome, composite, and efficiency measures. Cardiovascular performance measures using existing ACCF/AHA methodology are based on Class I or Class III guidelines recommendations, usually with Level A evidence. These performance measures, based on evidence-based ACCF/AHA guidelines, remain the most rigorous quality measures for both internal quality improvement and public reporting. However, many of the tools for diagnosis and treatment of cardiovascular disease involve advanced technologies, such as cardiac imaging, for which there are often no underlying guideline documents. Because these technologies affect the quality of cardiovascular care and also have the potential to contribute to cardiovascular health expenditures, there is a need for more critical assessment of the use of technology, including the development of quality and performance measures in areas in which guideline recommendations are absent. The evaluation of quality in the use of cardiovascular technologies requires consideration of multiple parameters that differ from other healthcare processes. The present document describes methodology for development of 2 new classes of quality measures in these situations, appropriate use measures and structure/safety measures. Appropriate use measures are based on specific indications, processes, or parameters of care for which high level of evidence data and Class I or Class III guideline recommendations may be lacking but are addressed in ACCF appropriate use criteria documents. Structure/safety measures represent measures developed to address structural aspects of the use of healthcare technology (e.g., laboratory accreditation, personnel training, and credentialing) or quality issues related to patient safety when there are neither guidelines recommendations nor appropriate use criteria. Although the strength of evidence for appropriate use measures and structure/safety measures may not be as strong as that for formal performance measures, they are quality measures that are otherwise rigorously developed, reviewed, tested, and approved in the same manner as ACCF/AHA performance measures. The ultimate goal of the present document is to provide direction in defining and measuring the appropriate use-avoiding not only underuse but also overuse and misuse-and proper application of cardiovascular technology and to describe how such appropriate use measures and structure/safety measures might be developed for the purposes of quality improvement and public reporting. It is anticipated that this effort will help focus the national dialogue on the use of cardiovascular technology and away from the current concerns about volume and cost alone to a more holistic emphasis on value.

ACCF/AHA methodology for the development of quality measures for cardiovascular technology: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Performance Measures.

Consistent with the growing national focus on healthcare quality, the American College of Cardiology Foundation (ACCF) and the American Heart Association (AHA) have taken a leadership role over the past decade in developing measures of the quality of cardiovascular care by convening a joint ACCF/AHA Task Force on Performance Measures. The Task Force is charged with identifying the clinical topics appropriate for the development of performance measures and with assembling writing committees composed of clinical and methodological experts in collaboration with appropriate subspecialty societies. The Task Force has also created methodology documents that offer guidance in the development of process, outcome, composite, and efficiency measures. Cardiovascular performance measures using existing ACCF/AHA methodology are based on Class I or Class III guidelines recommendations, usually with Level A evidence. These performance measures, based on evidence-based ACCF/AHA guidelines, remain the most rigorous quality measures for both internal quality improvement and public reporting. However, many of the tools for diagnosis and treatment of cardiovascular disease involve advanced technologies, such as cardiac imaging, for which there are often no underlying guideline documents. Because these technologies affect the quality of cardiovascular care and also have the potential to contribute to cardiovascular health expenditures, there is a need for more critical assessment of the use of technology, including the development of quality and performance measures in areas in which guideline recommendations are absent. The evaluation of quality in the use of cardiovascular technologies requires consideration of multiple parameters that differ from other healthcare processes. The present document describes methodology for development of 2 new classes of quality measures in these situations, appropriate use measures and structure/safety measures. Appropriate use measures are based on specific indications, processes, or parameters of care for which high level of evidence data and Class I or Class III guideline recommendations may be lacking but are addressed in ACCF appropriate use criteria documents. Structure/safety measures represent measures developed to address structural aspects of the use of healthcare technology (e.g., laboratory accreditation, personnel training, and credentialing) or quality issues related to patient safety when there are neither guidelines recommendations nor appropriate use criteria. Although the strength of evidence for appropriate use measures and structure/safety measures may not be as strong as that for formal performance measures, they are quality measures that are otherwise rigorously developed, reviewed, tested, and approved in the same manner as ACCF/AHA performance measures. The ultimate goal of the present document is to provide direction in defining and measuring the appropriate use-avoiding not only underuse but also overuse and misuse-and proper application of cardiovascular technology and to describe how such appropriate use measures and structure/safety measures might be developed for the purposes of quality improvement and public reporting. It is anticipated that this effort will help focus the national dialogue on the use of cardiovascular technology and away from the current concerns about volume and cost alone to a more holistic emphasis on value.

Age-dependent gender differences in hypertension management.

OBJECTIVE: Despite gender-neutral guidelines, prior studies suggest that women have lower rates of hypertension control and these differences may vary with age. Accordingly, we compared rates of hypertension control between women and men as a function of age. METHODS: Within three integrated healthcare systems in the Cardiovascular Research Network, we studied all patients seen from 2001 to 2007 with incident hypertension. Within 1 year of cohort entry, patient's hypertension was categorized as controlled based upon achieving guideline-recommended blood pressure levels, recognized if hypertension was diagnosed or a hypertension medication dispensed, and treated based on hypertension medications dispensed. Multivariable logistic regression models assessed the association between gender and 1-year hypertension outcomes, adjusted for patient characteristics. RESULTS: Among the 152,561 patients with incident hypertension, 55.6% were women. Compared to men, women were older, had more kidney disease and more blood pressure measures during follow-up. Overall, men tended to have lower rates of hypertension control compared to women (41.2 vs. 45.7%, adjusted odds ratio 0.93, 95% confidence interval 0.91-0.95). A significant gender by age interaction was found with men aged 18-49 having 17% lower odds of hypertension control and men aged at least 65 having 12% higher odds of hypertension control compared to women of similar ages (P<0.001). CONCLUSION: In this incident hypertension cohort, younger men and older women had lower rates of hypertension control compared to similarly aged peers. Future studies should investigate why gender differences vary by age in order to plan appropriate means of improving hypertension management regardless of gender or age.

The Cardiovascular Research Network: a new paradigm for cardiovascular quality and outcomes research.

BACKGROUND: A clear need exists for a more systematic understanding of the epidemiology, diagnosis, and management of cardiovascular diseases. More robust data are also needed on how well clinical trials are translated into contemporary community practice and the associated resource use, costs, and outcomes. METHODS AND RESULTS: The National Heart, Lung, and Blood Institute recently established the Cardiovascular Research Network, which represents a new paradigm to evaluate the epidemiology, quality of care, and outcomes of cardiovascular disease and to conduct future clinical trials using a community-based model. The network includes 15 geographically distributed health plans with dedicated research centers, National Heart, Lung, and Blood Institute representatives, and an external collaboration and advisory committee. Cardiovascular research network sites bring complementary content and methodological expertise and a diverse population of approximately 11 million individuals treated through various health care delivery models. Each site's rich electronic databases (eg, sociodemographic characteristics, inpatient and outpatient diagnoses and procedures, pharmacy, laboratory, and cost data) are being mapped to create a standardized virtual data warehouse to facilitate rapid and efficient large-scale research studies. Initial projects focus on (1) hypertension recognition and management, (2) quality and outcomes of warfarin therapy, and (3) use, outcomes, and costs of implantable cardioverter defibrillators. CONCLUSIONS: The Cardiovascular Research Network represents a new paradigm in the approach to cardiovascular quality of care and outcomes research among community-based populations. Its unique ability to characterize longitudinally large, diverse populations will yield novel insights into contemporary disease and risk factor surveillance, management, outcomes, and costs. The Cardiovascular Research Network aims to become the national research partner of choice for efforts to improve the prevention, diagnosis, treatment, and outcomes of cardiovascular diseases.