IntroductionNational breastfeeding rates have improved in recent years, however, disparities exis... more IntroductionNational breastfeeding rates have improved in recent years, however, disparities exist by socioeconomic and psychosocial factors. Suboptimal breastfeeding overburdens the society by increasing healthcare costs. Existing breastfeeding supports including education and peer support have not been sufficient in sustaining breastfeeding rates especially among low-income women. The preliminary outcomes of contingent incentives for breastfeeding in addition to existing support show promising effects in sustaining breastfeeding among mothers in the Special Supplemental Nutrition Programme for women, infants and children (WIC).Methods and analysisThis trial uses a parallel randomised controlled trial. This trial is conducted at two sites in separate states in the USA. Mothers who were enrolled in WIC and initiated breastfeeding are eligible. Participants (n=168) are randomised into one of the two study groups: (1) standard care control (SC) group consisting of WIC breastfeeding se...
IMPORTANCE The Reduction of Cardiovascular Events With Icosapent Ethyl-Intervention Trial (REDUCE... more IMPORTANCE The Reduction of Cardiovascular Events With Icosapent Ethyl-Intervention Trial (REDUCE-IT) demonstrated the efficacy of icosapent ethyl (IPE) for high-risk patients with hypertriglyceridemia and known cardiovascular disease or diabetes and at least 1 other risk factor who were treated with statins. OBJECTIVE To estimate the cost-effectiveness of IPE compared with standard care for high-risk patients with hypertriglyceridemia despite statin treatment. DESIGN, SETTING, AND PARTICIPANTS An in-trial cost-effectiveness analysis was performed using patient-level study data from REDUCE-IT, and a lifetime analysis was performed using a microsimulation model and data from published literature. The study included 8179 patients with
Circulation: Cardiovascular Quality and Outcomes, 2011
Background: Relief of angina and improvement in quality of life is the most common indication for... more Background: Relief of angina and improvement in quality of life is the most common indication for percutaneous coronary intervention (PCI) in stable ischemic heart disease (SIHD). Given that there are alternative strategies for treating angina, (e.g. intensifying optimal medical therapy (OMT) or PCI), predicting angina severity as a function of alternative treatment options can serve as a foundation for shared decision-making and the elicitation of patients’ preferences. Methods: Using data from the 2,287 SIHD patients in COURAGE trial, where PCI was randomized, we built multivariable linear regression models of Seattle Angina Questionnaire (SAQ)-assessed angina, physical function and quality of life at 6 and 12 months, using baseline SAQ scores, treatment, and all demographic and clinical characteristics available at the time of randomization. Results: At baseline, there were no significant differences between PCI and OMT groups for any SAQ domain. The strongest predictors of 6- an...
Background: The American College of Cardiology Foundation and The Society of Thoracic Surgeons Co... more Background: The American College of Cardiology Foundation and The Society of Thoracic Surgeons Collaboration on the Comparative Effectiveness of Revascularization Strategies (ASCERT) has demonstrated that coronary artery bypass graft (CABG) surgery was associated with reduced mortality compared to percutaneous coronary intervention (PCI) at 4 years. In this study, we examined the cost-effectiveness of CABG versus PCI for treatment of multivessel coronary artery disease (CAD) patients among unstable angina patients. Methods: Unstable angina age ≥65 year-old patients with stable 2 and 3-vessel disease undergoing revascularization from 2004 through 2008 were evaluated. Costs were assessed at index, study period from years 2004 to 2008 by Diagnosis Related Group for hospitalizations. The average Medicare participant per capita expenditure in 2004 was used to estimate cost beyond the study period. Effectiveness during the study period was measured via mortality rate. Costs and effectiven...
Circulation: Cardiovascular Quality and Outcomes, 2019
Background: In 2017, the American College of Cardiology (ACC) and the American Heart Association ... more Background: In 2017, the American College of Cardiology (ACC) and the American Heart Association (AHA) published guidelines on the diagnosis and treatment of high BP (blood pressure) in adults. The impact of clinic outcome and economy need to be estimated for adopting the guidelines in China. Methods: Data from a nationally representative sample in China were analyzed. The prevalence and treatment were calculated based on the criteria of the 2017 ACC/AHA and 2010 Chinese guidelines among participants aged ≥35 years old. Direct medical costs, as well as the averted disability adjusted of life years (DALYs) and cost saving from cardiovascular disease (CVD) events prevented by controlling hypertension, were also estimated. Results: The prevalence and treatment rate of hypertension was 32.0% and 43.4% according to the 2010 Chinese guidelines. Based on the 2017 ACC/AHA guidelines, another 24.5% of the adult population (estimated 168.1 million) would be classified with hypertension; of wh...
BACKGROUND Whether the direct factor Xa inhibitor rivaroxaban can prevent thromboembolic events a... more BACKGROUND Whether the direct factor Xa inhibitor rivaroxaban can prevent thromboembolic events after transcatheter aortic-valve replacement (TAVR) is unclear. METHODS We randomly assigned 1644 patients without an established indication for oral anticoagulation after successful TAVR to receive rivaroxaban at a dose of 10 mg daily (with aspirin at a dose of 75 to 100 mg daily for the first 3 months) (rivaroxaban group) or aspirin at a dose of 75 to 100 mg daily (with clopidogrel at a dose of 75 mg daily for the first 3 months) (antiplatelet group). The primary efficacy outcome was the composite of death or thromboembolic events. The primary safety outcome was major, disabling, or life-threatening bleeding. The trial was terminated prematurely by the data and safety monitoring board because of safety concerns. RESULTS After a median of 17 months, death or a first thromboembolic event (intention-to-treat analysis) had occurred in 105 patients in the rivaroxaban group and in 78 patients in the antiplatelet group (incidence rates, 9.8 and 7.2 per 100 person-years, respectively; hazard ratio with rivaroxaban, 1.35; 95% confidence interval [CI], 1.01 to 1.81; P = 0.04). Major, disabling, or life-threatening bleeding (intention-to-treat analysis) had occurred in 46 and 31 patients, respectively (4.3 and 2.8 per 100 person-years; hazard ratio, 1.50; 95% CI, 0.95 to 2.37; P = 0.08). A total of 64 deaths occurred in the rivaroxaban group and 38 in the antiplatelet group (5.8 and 3.4 per 100 personyears, respectively; hazard ratio, 1.69; 95% CI, 1.13 to 2.53). CONCLUSIONS In patients without an established indication for oral anticoagulation after successful TAVR, a treatment strategy including rivaroxaban at a dose of 10 mg daily was associated with a higher risk of death or thromboembolic complications and a higher risk of bleeding than an antiplatelet-based strategy. (Funded by Bayer and Janssen Pharmaceuticals; GALILEO ClinicalTrials.gov number, NCT02556203.
Purpose: Missing data present a challenge for analysis, particularly data from clinical databases... more Purpose: Missing data present a challenge for analysis, particularly data from clinical databases and patient registries where missing values are not easily obtained after the initial data collection, or cannot be obtained at all. Additionally, there is the issue of whether data are at least missing at random (MAR) and the implications for imputing missing values. In this study, we assess the relationship between cardiovascular (CV) events, chronic kidney disease (CKD) and obesity. Specifically, we investigated the impact of missing body mass index (BMI) values in a clinical database of 36,000 patients with nearly 600,000 observations over a 10+ year period. Method: Parametric regression models, latent growth curve modeling and hierarchical Poisson regression, were used to assess whether a longitudinal decline in kidney function modifies the association between obesity and cardiovascular events. Because the parametric models excluded patients with missing data, time series of CV eve...
This retrospective study of office and hospital electronic medical records from June 1991 to June... more This retrospective study of office and hospital electronic medical records from June 1991 to June 2007 examines the occurrence of severe blood pressure (BP) elevation (>180/110 mm Hg) and the subsequent risk of cardiovascular events in a diverse set of primary care practices. A total of 18,747 patients were categorized according to BP using 3 methodologies based on the highest historical value, the first recorded value, and time-averaged antecedent values. During the follow-up period (median 3.8 years) there were 949 cardiovascular events and 80 cardiovascular-related deaths. Severe BP elevation occurred in 1566 (8.4%) patients. The age-adjusted incidence of cardiovascular events per 1000 patient-years was 5.9 in the normal BP group, 10.1 in the mild group, 15.1 in the moderate group, and 25.0 in the severe group. An episode of severe BP elevation is common in primary care practice and is associated with substantial excess cardiovascular morbidity.
Circulation: Cardiovascular Quality and Outcomes, 2013
Introduction: Major clinical trials involve any number of sites in order to enroll enough patient... more Introduction: Major clinical trials involve any number of sites in order to enroll enough patients to adequately power the study. In addition, sites enrolling patients in a trial may belong to different health systems (e.g., countries). Differences among patients and practices of these systems/sites potentially introduces a component of variation that may affect the results of the statistical analysis of the data, and thus the conclusions of the study. In this study, we examined the impact of the multilevel nature of the COURAGE Trial on the analysis of patients’ quality of life data. Methods: The aim of the COURAGE Trial was to determine whether the addition of PCI to optimal medical therapy, when used as an initial management strategy, reduces the risk of death or nonfatal MI in patients with stable CAD, compared with optimal medical therapy alone. A total of 2,287 CAD patients were enrolled from 3 health care systems: Canadian (16), VA (15) and US non-VA (19) hospitals. A 3-level...
Background For hypertensive patients without a history of stroke or myocardial infarction (MI), t... more Background For hypertensive patients without a history of stroke or myocardial infarction (MI), the China Stroke Primary Prevention Trial (CSPPT) demonstrated that treatment with enalapril-folic acid reduced the risk of primary stroke compared with enalapril alone. Whether folic acid therapy is an affordable and beneficial treatment strategy for the primary prevention of stroke in hypertensive patients from the Chinese healthcare sector perspective has not been thoroughly explored. Methods We performed a cost-effectiveness analysis alongside the CSPPT, which randomized 20,702 hypertensive patients. A patient-level microsimulation model based on the 4.5-year period of in-trial data was used to estimate costs, life years, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs) for enalapril-folic acid vs. enalapril over a lifetime horizon from the payer perspective. Results During the in-trial follow-up period, patients receiving enalapril-folic acid gai...
Circulation: Cardiovascular Quality and Outcomes, 2013
Background: The ASCERT--American College of Cardiology Foundation (ACCF) - Society of Thoracic Su... more Background: The ASCERT--American College of Cardiology Foundation (ACCF) - Society of Thoracic Surgeons (STS) Database Collaboration on the Comparative Effectiveness of Revascularization Strategies study - has demonstrated that coronary artery bypass graft (CABG) surgery was associated with reduced mortality compared to percutaneous coronary intervention (PCI) at 4 years. In this study, we examined the cost-effectiveness of CABG versus PCI for treatment of multivessel coronary disease patients among diabetes patients. Methods: Diabetes Patients age ≥65 years with stable 2 and 3-vessel disease undergoing revascularization from 2004 through 2008 were evaluated. CABG patients with diabetes were selected from the STS National Database and the PCI patient population from The ACCF National Cardiovascular Data Registry. Costs were assessed at index, study period from years 2004 to 2008 by Diagnosis Related Group for hospitalizations. The average Medicare participant per capita expenditure ...
Background: The impact of aortic valve replacement (AVR) versus medical management (MM) in patien... more Background: The impact of aortic valve replacement (AVR) versus medical management (MM) in patients with paradoxical low flow is unclear. The objective of this study was to compare outcomes of AVR versus MM in patients with severe aortic stenosis and normal ejection fraction and different transaortic flow and gradient. Methods: We identified consecutive patients presenting to our echo lab with an aortic valve area (AVA) < 1.0cm 2 and EF≥ 50%. We stratify patients depending on gradient (≥ 40 vs. < 40 mmHg) and stroke volume index (SVI < 35 vs. ≥35 ml/m 2 ). 4 groups were identified (, normal flow, high gradient [NF/HG]; normal flow, low gradient [NF/LG]; low flow, high gradient [LF/HG] and low flow, low gradient [LF/LG]. These 4 groups were also stratified depending on management (AVR vs. MM). All patients were retrospectively followed for the occurrence of death. Results: A total of 954 patients were included in analysis. Mean follow up was 2.45 ± 1.9 years. The mean age wa...
Journal of the American College of Cardiology, 2021
BACKGROUND Intensive systolic blood pressure (SBP) treatment prevents cardiovascular disease (CVD... more BACKGROUND Intensive systolic blood pressure (SBP) treatment prevents cardiovascular disease (CVD) events in patients with high CVD risk on average, though benefits likely vary among patients. OBJECTIVES The aim of this study was to predict the magnitude of benefit (reduced CVD and all-cause mortality risk) along with adverse event (AE) risk from intensive versus standard SBP treatment. METHODS This was a secondary analysis of SPRINT (Systolic Blood Pressure Intervention Trial). Separate benefit outcomes were the first occurrence of: 1) a CVD composite of acute myocardial infarction or other acute coronary syndrome, stroke, heart failure, or CVD death; and 2) all-cause mortality. Treatment-related AEs of interest included hypotension, syncope, bradycardia, electrolyte abnormalities, injurious falls, and acute kidney injury. Modified elastic net Cox regression was used to predict absolute risk for each outcome and absolute risk differences on the basis of 36 baseline variables available at the point of care with intensive versus standard treatment. RESULTS Among 8,828 SPRINT participants (mean age 67.9 years, 35% women), 600 CVD composite events, 363 all-cause deaths, and 481 treatment-related AEs occurred over a median follow-up period of 3.26 years. Individual participant risks were predicted for the CVD composite (C index = 0.71), all-cause mortality (C index = 0.75), and treatment-related AEs (C index = 0.69). Higher baseline CVD risk was associated with greater benefit (i.e., larger absolute CVD risk reduction). Predicted CVD benefit and predicted increased treatment-related AE risk were correlated (Spearman correlation coefficient = -0.72), and 95% of participants who fell into the highest tertile of predicted benefit also had high or moderate predicted increases in treatment-related AE risk. Few were predicted as high benefit with low AE risk (1.8%) or low benefit with high AE risk (1.5%). Similar results were obtained for all-cause mortality. CONCLUSIONS SPRINT participants with higher baseline predicted CVD risk gained greater absolute benefit from intensive treatment. Participants with high predicted benefit were also most likely to experience treatment-related AEs, but AEs were generally mild and transient. Patients should be prioritized for intensive SBP treatment on the basis of higher predicted benefit. (Systolic Blood Pressure Intervention Trial [SPRINT]; NCT01206062).
Circulation: Cardiovascular Quality and Outcomes, 2011
Background: The COURAGE trial compared percutaneous coronary intervention (PCI) plus optimal medi... more Background: The COURAGE trial compared percutaneous coronary intervention (PCI) plus optimal medical therapy (OMT) to OMT alone in reducing the risk of cardiovascular events in 2287 patients with stable coronary disease. We examined the impact of PCI and other risk factors on clinically significant improvements in quality of life measures. Methods: Angina-specific and overall health status were assessed with the Seattle Angina Questionnaire (SAQ) and RAND-36 respectively, at baseline and at 1, 3, 6 and 12 months followed by annual evaluations. Scores range from 0 to 100; higher scores indicate better health status. Clinically significant improvement from baseline within individual patients was defined as score increases of ≥8, ≥25, ≥20, ≥12, and ≥16 for physical limitation, angina stability, angina frequency, treatment satisfaction, and quality of life domains respectively in SAQ and ≥ 10 for each domain in RAND-36. Results: Adjusted for other demographic and comorbidity risk factor...
Background: Increased life expectancy and improved medical technology allow increasing numbers of... more Background: Increased life expectancy and improved medical technology allow increasing numbers of elderly patients to undergo cardiac surgery. Elderly patients may be at greater risk of postoperative morbidity and mortality. Complications can lead to worsened quality of life, shortened life expectancy and higher healthcare costs. Reducing perioperative complications, especially severe adverse events, is key to improving outcomes in patients undergoing cardiac surgery. The objective of this study is to determine whether perioperative lipid-lowering medication use is associated with a reduced risk of complications and mortality after coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). Methods: After IRB approval, we reviewed charts of 9,518 patients who underwent cardiac surgery with CPB at three medical centers between July 2001 and June 2015. The relationship between perioperative lipid-lowering treatment and postoperative outcome was investigated. 3,988 patien...
Background: In high-risk adults, intensive systolic blood pressure (SBP) goals (<120 mmHg) red... more Background: In high-risk adults, intensive systolic blood pressure (SBP) goals (<120 mmHg) reduced cardiovascular disease (CVD) events and mortality, when compared to standard SBP goals (<140 mmHg), in the Systolic Blood Pressure Intervention Trial (SPRINT). While average benefit of reduced CVD risk with intensive SBP goals outweighs the average risk of serious adverse events (SAEs) and treatment costs, net intensive SBP goal benefits may vary by baseline SBP. We hypothesized that intensive SBP goals would be cost-effective vs. standard SBP goals when stratified by baseline SBP level in SPRINT-eligible US adults from the payer’s perspective. Methods: Using CVD event, death, and SAE risks, a microsimulation model compared direct healthcare costs and quality-adjusted life-years (QALYs) in the SPRINT intensive and standard SBP goal arms over patients’ remaining lifetimes. Published literature and national estimates were used for model parameters. The model assumed that, after the...
Background: Prolonged hospital stay (PHS) has been a costly health care issue. Using data from th... more Background: Prolonged hospital stay (PHS) has been a costly health care issue. Using data from the Society of Thoracic Surgeons (STS) Database and the American College of Cardiology Foundation (ACCF) National Cardiovascular Data Registry (NCDR) in ASCERT, we examined the determinants of PHS in a 30-day period after the index hospitalization for patients undergoing coronary-artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI). Methods: The STS Database and ACCF NCDR were linked to the Centers for Medicare and Medicaid Services claims data from years 2004 to 2008 for patients who were age ≥65 years with stable 2 and 3-vessel disease undergoing revascularization. The length of stay >7 days in CABG and >2 days in PCI patients was defined as PHS, respectively; the determinants of PHS in a 30-day period after the index hospitalization for CABG and PCI patients were examined. Results: By 30 days, 40,694 (47.18%) of 86,244 in CABG group and 32,789 (31.67%) of ...
IntroductionNational breastfeeding rates have improved in recent years, however, disparities exis... more IntroductionNational breastfeeding rates have improved in recent years, however, disparities exist by socioeconomic and psychosocial factors. Suboptimal breastfeeding overburdens the society by increasing healthcare costs. Existing breastfeeding supports including education and peer support have not been sufficient in sustaining breastfeeding rates especially among low-income women. The preliminary outcomes of contingent incentives for breastfeeding in addition to existing support show promising effects in sustaining breastfeeding among mothers in the Special Supplemental Nutrition Programme for women, infants and children (WIC).Methods and analysisThis trial uses a parallel randomised controlled trial. This trial is conducted at two sites in separate states in the USA. Mothers who were enrolled in WIC and initiated breastfeeding are eligible. Participants (n=168) are randomised into one of the two study groups: (1) standard care control (SC) group consisting of WIC breastfeeding se...
IMPORTANCE The Reduction of Cardiovascular Events With Icosapent Ethyl-Intervention Trial (REDUCE... more IMPORTANCE The Reduction of Cardiovascular Events With Icosapent Ethyl-Intervention Trial (REDUCE-IT) demonstrated the efficacy of icosapent ethyl (IPE) for high-risk patients with hypertriglyceridemia and known cardiovascular disease or diabetes and at least 1 other risk factor who were treated with statins. OBJECTIVE To estimate the cost-effectiveness of IPE compared with standard care for high-risk patients with hypertriglyceridemia despite statin treatment. DESIGN, SETTING, AND PARTICIPANTS An in-trial cost-effectiveness analysis was performed using patient-level study data from REDUCE-IT, and a lifetime analysis was performed using a microsimulation model and data from published literature. The study included 8179 patients with
Circulation: Cardiovascular Quality and Outcomes, 2011
Background: Relief of angina and improvement in quality of life is the most common indication for... more Background: Relief of angina and improvement in quality of life is the most common indication for percutaneous coronary intervention (PCI) in stable ischemic heart disease (SIHD). Given that there are alternative strategies for treating angina, (e.g. intensifying optimal medical therapy (OMT) or PCI), predicting angina severity as a function of alternative treatment options can serve as a foundation for shared decision-making and the elicitation of patients’ preferences. Methods: Using data from the 2,287 SIHD patients in COURAGE trial, where PCI was randomized, we built multivariable linear regression models of Seattle Angina Questionnaire (SAQ)-assessed angina, physical function and quality of life at 6 and 12 months, using baseline SAQ scores, treatment, and all demographic and clinical characteristics available at the time of randomization. Results: At baseline, there were no significant differences between PCI and OMT groups for any SAQ domain. The strongest predictors of 6- an...
Background: The American College of Cardiology Foundation and The Society of Thoracic Surgeons Co... more Background: The American College of Cardiology Foundation and The Society of Thoracic Surgeons Collaboration on the Comparative Effectiveness of Revascularization Strategies (ASCERT) has demonstrated that coronary artery bypass graft (CABG) surgery was associated with reduced mortality compared to percutaneous coronary intervention (PCI) at 4 years. In this study, we examined the cost-effectiveness of CABG versus PCI for treatment of multivessel coronary artery disease (CAD) patients among unstable angina patients. Methods: Unstable angina age ≥65 year-old patients with stable 2 and 3-vessel disease undergoing revascularization from 2004 through 2008 were evaluated. Costs were assessed at index, study period from years 2004 to 2008 by Diagnosis Related Group for hospitalizations. The average Medicare participant per capita expenditure in 2004 was used to estimate cost beyond the study period. Effectiveness during the study period was measured via mortality rate. Costs and effectiven...
Circulation: Cardiovascular Quality and Outcomes, 2019
Background: In 2017, the American College of Cardiology (ACC) and the American Heart Association ... more Background: In 2017, the American College of Cardiology (ACC) and the American Heart Association (AHA) published guidelines on the diagnosis and treatment of high BP (blood pressure) in adults. The impact of clinic outcome and economy need to be estimated for adopting the guidelines in China. Methods: Data from a nationally representative sample in China were analyzed. The prevalence and treatment were calculated based on the criteria of the 2017 ACC/AHA and 2010 Chinese guidelines among participants aged ≥35 years old. Direct medical costs, as well as the averted disability adjusted of life years (DALYs) and cost saving from cardiovascular disease (CVD) events prevented by controlling hypertension, were also estimated. Results: The prevalence and treatment rate of hypertension was 32.0% and 43.4% according to the 2010 Chinese guidelines. Based on the 2017 ACC/AHA guidelines, another 24.5% of the adult population (estimated 168.1 million) would be classified with hypertension; of wh...
BACKGROUND Whether the direct factor Xa inhibitor rivaroxaban can prevent thromboembolic events a... more BACKGROUND Whether the direct factor Xa inhibitor rivaroxaban can prevent thromboembolic events after transcatheter aortic-valve replacement (TAVR) is unclear. METHODS We randomly assigned 1644 patients without an established indication for oral anticoagulation after successful TAVR to receive rivaroxaban at a dose of 10 mg daily (with aspirin at a dose of 75 to 100 mg daily for the first 3 months) (rivaroxaban group) or aspirin at a dose of 75 to 100 mg daily (with clopidogrel at a dose of 75 mg daily for the first 3 months) (antiplatelet group). The primary efficacy outcome was the composite of death or thromboembolic events. The primary safety outcome was major, disabling, or life-threatening bleeding. The trial was terminated prematurely by the data and safety monitoring board because of safety concerns. RESULTS After a median of 17 months, death or a first thromboembolic event (intention-to-treat analysis) had occurred in 105 patients in the rivaroxaban group and in 78 patients in the antiplatelet group (incidence rates, 9.8 and 7.2 per 100 person-years, respectively; hazard ratio with rivaroxaban, 1.35; 95% confidence interval [CI], 1.01 to 1.81; P = 0.04). Major, disabling, or life-threatening bleeding (intention-to-treat analysis) had occurred in 46 and 31 patients, respectively (4.3 and 2.8 per 100 person-years; hazard ratio, 1.50; 95% CI, 0.95 to 2.37; P = 0.08). A total of 64 deaths occurred in the rivaroxaban group and 38 in the antiplatelet group (5.8 and 3.4 per 100 personyears, respectively; hazard ratio, 1.69; 95% CI, 1.13 to 2.53). CONCLUSIONS In patients without an established indication for oral anticoagulation after successful TAVR, a treatment strategy including rivaroxaban at a dose of 10 mg daily was associated with a higher risk of death or thromboembolic complications and a higher risk of bleeding than an antiplatelet-based strategy. (Funded by Bayer and Janssen Pharmaceuticals; GALILEO ClinicalTrials.gov number, NCT02556203.
Purpose: Missing data present a challenge for analysis, particularly data from clinical databases... more Purpose: Missing data present a challenge for analysis, particularly data from clinical databases and patient registries where missing values are not easily obtained after the initial data collection, or cannot be obtained at all. Additionally, there is the issue of whether data are at least missing at random (MAR) and the implications for imputing missing values. In this study, we assess the relationship between cardiovascular (CV) events, chronic kidney disease (CKD) and obesity. Specifically, we investigated the impact of missing body mass index (BMI) values in a clinical database of 36,000 patients with nearly 600,000 observations over a 10+ year period. Method: Parametric regression models, latent growth curve modeling and hierarchical Poisson regression, were used to assess whether a longitudinal decline in kidney function modifies the association between obesity and cardiovascular events. Because the parametric models excluded patients with missing data, time series of CV eve...
This retrospective study of office and hospital electronic medical records from June 1991 to June... more This retrospective study of office and hospital electronic medical records from June 1991 to June 2007 examines the occurrence of severe blood pressure (BP) elevation (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;180/110 mm Hg) and the subsequent risk of cardiovascular events in a diverse set of primary care practices. A total of 18,747 patients were categorized according to BP using 3 methodologies based on the highest historical value, the first recorded value, and time-averaged antecedent values. During the follow-up period (median 3.8 years) there were 949 cardiovascular events and 80 cardiovascular-related deaths. Severe BP elevation occurred in 1566 (8.4%) patients. The age-adjusted incidence of cardiovascular events per 1000 patient-years was 5.9 in the normal BP group, 10.1 in the mild group, 15.1 in the moderate group, and 25.0 in the severe group. An episode of severe BP elevation is common in primary care practice and is associated with substantial excess cardiovascular morbidity.
Circulation: Cardiovascular Quality and Outcomes, 2013
Introduction: Major clinical trials involve any number of sites in order to enroll enough patient... more Introduction: Major clinical trials involve any number of sites in order to enroll enough patients to adequately power the study. In addition, sites enrolling patients in a trial may belong to different health systems (e.g., countries). Differences among patients and practices of these systems/sites potentially introduces a component of variation that may affect the results of the statistical analysis of the data, and thus the conclusions of the study. In this study, we examined the impact of the multilevel nature of the COURAGE Trial on the analysis of patients’ quality of life data. Methods: The aim of the COURAGE Trial was to determine whether the addition of PCI to optimal medical therapy, when used as an initial management strategy, reduces the risk of death or nonfatal MI in patients with stable CAD, compared with optimal medical therapy alone. A total of 2,287 CAD patients were enrolled from 3 health care systems: Canadian (16), VA (15) and US non-VA (19) hospitals. A 3-level...
Background For hypertensive patients without a history of stroke or myocardial infarction (MI), t... more Background For hypertensive patients without a history of stroke or myocardial infarction (MI), the China Stroke Primary Prevention Trial (CSPPT) demonstrated that treatment with enalapril-folic acid reduced the risk of primary stroke compared with enalapril alone. Whether folic acid therapy is an affordable and beneficial treatment strategy for the primary prevention of stroke in hypertensive patients from the Chinese healthcare sector perspective has not been thoroughly explored. Methods We performed a cost-effectiveness analysis alongside the CSPPT, which randomized 20,702 hypertensive patients. A patient-level microsimulation model based on the 4.5-year period of in-trial data was used to estimate costs, life years, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs) for enalapril-folic acid vs. enalapril over a lifetime horizon from the payer perspective. Results During the in-trial follow-up period, patients receiving enalapril-folic acid gai...
Circulation: Cardiovascular Quality and Outcomes, 2013
Background: The ASCERT--American College of Cardiology Foundation (ACCF) - Society of Thoracic Su... more Background: The ASCERT--American College of Cardiology Foundation (ACCF) - Society of Thoracic Surgeons (STS) Database Collaboration on the Comparative Effectiveness of Revascularization Strategies study - has demonstrated that coronary artery bypass graft (CABG) surgery was associated with reduced mortality compared to percutaneous coronary intervention (PCI) at 4 years. In this study, we examined the cost-effectiveness of CABG versus PCI for treatment of multivessel coronary disease patients among diabetes patients. Methods: Diabetes Patients age ≥65 years with stable 2 and 3-vessel disease undergoing revascularization from 2004 through 2008 were evaluated. CABG patients with diabetes were selected from the STS National Database and the PCI patient population from The ACCF National Cardiovascular Data Registry. Costs were assessed at index, study period from years 2004 to 2008 by Diagnosis Related Group for hospitalizations. The average Medicare participant per capita expenditure ...
Background: The impact of aortic valve replacement (AVR) versus medical management (MM) in patien... more Background: The impact of aortic valve replacement (AVR) versus medical management (MM) in patients with paradoxical low flow is unclear. The objective of this study was to compare outcomes of AVR versus MM in patients with severe aortic stenosis and normal ejection fraction and different transaortic flow and gradient. Methods: We identified consecutive patients presenting to our echo lab with an aortic valve area (AVA) < 1.0cm 2 and EF≥ 50%. We stratify patients depending on gradient (≥ 40 vs. < 40 mmHg) and stroke volume index (SVI < 35 vs. ≥35 ml/m 2 ). 4 groups were identified (, normal flow, high gradient [NF/HG]; normal flow, low gradient [NF/LG]; low flow, high gradient [LF/HG] and low flow, low gradient [LF/LG]. These 4 groups were also stratified depending on management (AVR vs. MM). All patients were retrospectively followed for the occurrence of death. Results: A total of 954 patients were included in analysis. Mean follow up was 2.45 ± 1.9 years. The mean age wa...
Journal of the American College of Cardiology, 2021
BACKGROUND Intensive systolic blood pressure (SBP) treatment prevents cardiovascular disease (CVD... more BACKGROUND Intensive systolic blood pressure (SBP) treatment prevents cardiovascular disease (CVD) events in patients with high CVD risk on average, though benefits likely vary among patients. OBJECTIVES The aim of this study was to predict the magnitude of benefit (reduced CVD and all-cause mortality risk) along with adverse event (AE) risk from intensive versus standard SBP treatment. METHODS This was a secondary analysis of SPRINT (Systolic Blood Pressure Intervention Trial). Separate benefit outcomes were the first occurrence of: 1) a CVD composite of acute myocardial infarction or other acute coronary syndrome, stroke, heart failure, or CVD death; and 2) all-cause mortality. Treatment-related AEs of interest included hypotension, syncope, bradycardia, electrolyte abnormalities, injurious falls, and acute kidney injury. Modified elastic net Cox regression was used to predict absolute risk for each outcome and absolute risk differences on the basis of 36 baseline variables available at the point of care with intensive versus standard treatment. RESULTS Among 8,828 SPRINT participants (mean age 67.9 years, 35% women), 600 CVD composite events, 363 all-cause deaths, and 481 treatment-related AEs occurred over a median follow-up period of 3.26 years. Individual participant risks were predicted for the CVD composite (C index = 0.71), all-cause mortality (C index = 0.75), and treatment-related AEs (C index = 0.69). Higher baseline CVD risk was associated with greater benefit (i.e., larger absolute CVD risk reduction). Predicted CVD benefit and predicted increased treatment-related AE risk were correlated (Spearman correlation coefficient = -0.72), and 95% of participants who fell into the highest tertile of predicted benefit also had high or moderate predicted increases in treatment-related AE risk. Few were predicted as high benefit with low AE risk (1.8%) or low benefit with high AE risk (1.5%). Similar results were obtained for all-cause mortality. CONCLUSIONS SPRINT participants with higher baseline predicted CVD risk gained greater absolute benefit from intensive treatment. Participants with high predicted benefit were also most likely to experience treatment-related AEs, but AEs were generally mild and transient. Patients should be prioritized for intensive SBP treatment on the basis of higher predicted benefit. (Systolic Blood Pressure Intervention Trial [SPRINT]; NCT01206062).
Circulation: Cardiovascular Quality and Outcomes, 2011
Background: The COURAGE trial compared percutaneous coronary intervention (PCI) plus optimal medi... more Background: The COURAGE trial compared percutaneous coronary intervention (PCI) plus optimal medical therapy (OMT) to OMT alone in reducing the risk of cardiovascular events in 2287 patients with stable coronary disease. We examined the impact of PCI and other risk factors on clinically significant improvements in quality of life measures. Methods: Angina-specific and overall health status were assessed with the Seattle Angina Questionnaire (SAQ) and RAND-36 respectively, at baseline and at 1, 3, 6 and 12 months followed by annual evaluations. Scores range from 0 to 100; higher scores indicate better health status. Clinically significant improvement from baseline within individual patients was defined as score increases of ≥8, ≥25, ≥20, ≥12, and ≥16 for physical limitation, angina stability, angina frequency, treatment satisfaction, and quality of life domains respectively in SAQ and ≥ 10 for each domain in RAND-36. Results: Adjusted for other demographic and comorbidity risk factor...
Background: Increased life expectancy and improved medical technology allow increasing numbers of... more Background: Increased life expectancy and improved medical technology allow increasing numbers of elderly patients to undergo cardiac surgery. Elderly patients may be at greater risk of postoperative morbidity and mortality. Complications can lead to worsened quality of life, shortened life expectancy and higher healthcare costs. Reducing perioperative complications, especially severe adverse events, is key to improving outcomes in patients undergoing cardiac surgery. The objective of this study is to determine whether perioperative lipid-lowering medication use is associated with a reduced risk of complications and mortality after coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). Methods: After IRB approval, we reviewed charts of 9,518 patients who underwent cardiac surgery with CPB at three medical centers between July 2001 and June 2015. The relationship between perioperative lipid-lowering treatment and postoperative outcome was investigated. 3,988 patien...
Background: In high-risk adults, intensive systolic blood pressure (SBP) goals (<120 mmHg) red... more Background: In high-risk adults, intensive systolic blood pressure (SBP) goals (<120 mmHg) reduced cardiovascular disease (CVD) events and mortality, when compared to standard SBP goals (<140 mmHg), in the Systolic Blood Pressure Intervention Trial (SPRINT). While average benefit of reduced CVD risk with intensive SBP goals outweighs the average risk of serious adverse events (SAEs) and treatment costs, net intensive SBP goal benefits may vary by baseline SBP. We hypothesized that intensive SBP goals would be cost-effective vs. standard SBP goals when stratified by baseline SBP level in SPRINT-eligible US adults from the payer’s perspective. Methods: Using CVD event, death, and SAE risks, a microsimulation model compared direct healthcare costs and quality-adjusted life-years (QALYs) in the SPRINT intensive and standard SBP goal arms over patients’ remaining lifetimes. Published literature and national estimates were used for model parameters. The model assumed that, after the...
Background: Prolonged hospital stay (PHS) has been a costly health care issue. Using data from th... more Background: Prolonged hospital stay (PHS) has been a costly health care issue. Using data from the Society of Thoracic Surgeons (STS) Database and the American College of Cardiology Foundation (ACCF) National Cardiovascular Data Registry (NCDR) in ASCERT, we examined the determinants of PHS in a 30-day period after the index hospitalization for patients undergoing coronary-artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI). Methods: The STS Database and ACCF NCDR were linked to the Centers for Medicare and Medicaid Services claims data from years 2004 to 2008 for patients who were age ≥65 years with stable 2 and 3-vessel disease undergoing revascularization. The length of stay >7 days in CABG and >2 days in PCI patients was defined as PHS, respectively; the determinants of PHS in a 30-day period after the index hospitalization for CABG and PCI patients were examined. Results: By 30 days, 40,694 (47.18%) of 86,244 in CABG group and 32,789 (31.67%) of ...
Uploads
Papers by Zugui Zhang