Lisandro D. Colantonio

Validation of the atherosclerotic cardiovascular disease Pooled Cohort risk equations.

IMPORTANCE The American College of Cardiology/American Heart Association (ACC/AHA) Pooled Cohort risk equations were developed to estimate atherosclerotic cardiovascular disease (CVD) risk and guide statin initiation. OBJECTIVE To assess calibration and discrimination of the Pooled Cohort risk equations in a contemporary US population. DESIGN, SETTING, AND PARTICIPANTS Adults aged 45 to 79 years enrolled in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study between January 2003 and October 2007 and followed up through December 2010. We studied participants for whom atherosclerotic CVD risk may trigger a discussion of statin initiation (those without clinical atherosclerotic CVD or diabetes, low-density lipoprotein cholesterol level between 70 and 189 mg/dL, and not taking statins; n = 10,997). MAIN OUTCOMES AND MEASURES Predicted risk and observed adjudicated atherosclerotic CVD incidence (nonfatal myocardial infarction, coronary heart disease [CHD] death, nonfatal or fatal stroke) at 5 years because REGARDS participants have not been followed up for 10 years. Additional analyses, limited to Medicare beneficiaries (n = 3333), added atherosclerotic CVD events identified in Medicare claims data. RESULTS There were 338 adjudicated events (192 CHD events, 146 strokes). The observed and predicted 5-year atherosclerotic CVD incidence per 1000 person-years for participants with a 10-year predicted atherosclerotic CVD risk of less than 5% was 1.9 (95% CI, 1.3-2.7) and 1.9, respectively, risk of 5% to less than 7.5% was 4.8 (95% CI, 3.4-6.7) and 4.8, risk of 7.5% to less than 10% was 6.1 (95% CI, 4.4-8.6) and 6.9, and risk of 10% or greater was 12.0 (95% CI, 10.6-13.6) and 15.1 (Hosmer-Lemeshow χ2 = 19.9, P = .01). The C index was 0.72 (95% CI, 0.70-0.75). There were 234 atherosclerotic CVD events (120 CHD events, 114 strokes) among Medicare-linked participants and the observed and predicted 5-year atherosclerotic CVD incidence per 1000 person-years for participants with a predicted risk of less than 7.5% was 5.3 (95% CI, 2.8-10.1) and 4.0, respectively, risk of 7.5% to less than 10% was 7.9 (95% CI, 4.6-13.5) and 6.4, and risk of 10% or greater was 17.4 (95% CI, 15.3-19.8) and 16.4 (Hosmer-Lemeshow χ2 = 5.4, P = .71). The C index was 0.67 (95% CI, 0.64-0.71). CONCLUSIONS AND RELEVANCE In this cohort of US adults for whom statin initiation is considered based on the ACC/AHA Pooled Cohort risk equations, observed and predicted 5-year atherosclerotic CVD risks were similar, indicating that these risk equations were well calibrated in the population for which they were designed to be used, and demonstrated moderate to good discrimination.

Visit-to-Visit Variability of Blood Pressure and Coronary Heart Disease, Stroke, Heart Failure, and Mortality: A Cohort Study

Context It is not clear whether variability in a patients outpatient blood pressure (BP) measurements has prognostic importance. Contribution Patients with greater visit-to-visit variability in BP readings had an increased risk for cardiovascular events and mortality, which was independent of their overall degree of BP control. Implication Further studies are warranted to assess whether reducing visit-to-visit BP variations will alter the risk for adverse cardiovascular outcomes. The prognostic value of blood pressure (BP) is mainly based on measurements obtained in a clinical setting, typically from a few visits (1). Until recently, variability of BP across outpatient visits was dismissed as random fluctuation around a patients true underlying BP (2, 3). Although some studies have reported associations between higher visit-to-visit variability (VVV) of systolic BP (SBP) and an increased risk for stroke and coronary heart disease (CHD), other analyses have failed to show such associations (410). The method applied in estimating VVV of BP varied widely across previous studies. In addition, studies have used as few as 3 visits and as many as 56 visits to estimate the VVV of BP, and the time between visits has ranged from 2 days to as long as 4 years (5, 11, 12). These factors not only influence VVV of BP but could also affect the strength of its association with cardiovascular disease (CVD) outcomes (4, 13). To address the inconsistent findings from previous studies, we did a secondary data analysis of ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) to examine whether VVV of BP is associated with CVD and mortality events. ALLHAT provides the opportunity to evaluate the association between VVV of BP and major clinical outcomes in a large and diverse population with hypertension in which visits were conducted at set time intervals, BP was measured by following a standardized protocol, and outcomes were evaluated over several years of follow-up. Methods Study Design We did a cohort study as a secondary analysis using data from ALLHAT. Figure 1 shows the timeline for assessment of VVV of BP and outcome events within ALLHAT. The primary exposure of interest, VVV of SBP, was ascertained at the 7 study visits conducted between 6 and 28 months after randomization. We studied 4 outcomes: fatal CHD or nonfatal myocardial infarction (MI), all-cause mortality, stroke, and heart failure. Participants were followed from their 28-month visit until the occurrence of an outcome event or the end of active ALLHAT follow-up (October 2001 to March 2002). Participants who had an event before their 28-month visit were excluded from all analyses. Figure 1. Study design evaluating the association between VVV of BP and cardiovascular outcomes and all-cause mortality in ALLHAT. ALLHAT = Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial; BP = blood pressure; DBP = diastolic blood pressure; SBP = systolic blood pressure; VVV = visit-to-visit variability. * Participants were followed for a mean of 2.7 to 2.9 y (maximum, 5.7 y) depending on the outcome after assessment of VVV of BP. ALLHAT was a multicenter, double-blind, randomized clinical trial sponsored by the National Heart, Lung, and Blood Institute of the National Institutes of Health. A complete description of the rationale and design of ALLHAT has been previously published (14). In brief, ALLHAT was designed to determine whether treatment initiated with a calcium-channel blocker (amlodipine), angiotensin-converting enzyme inhibitor (lisinopril), or -blocker (doxazosin)each compared with treatment initiated with a diuretic (chlorthalidone)would lower major cardiovascular outcomes. The primary end point was incidence of fatal CHD or nonfatal MI. A total of 42418 hypertensive adults aged 55 years or older with 1 or more additional risk factor for CVD were enrolled at 623 clinical sites across the United States, Canada, Puerto Rico, and the U.S. Virgin Islands between February 1994 and January 1998. The doxazosin treatment group was discontinued in 2000 because of the small chance of finding a benefit on CHD outcomes and an increased risk for CVD than in the chlorthalidone group (15). The main results comparing participants randomly assigned to chlorthalidone, amlodipine, or lisinopril were published in December 2002 (16). The trial was approved by local institutional review boards, and all participants provided written informed consent. Our current analysis was approved by the Institutional Review Board at the University of Alabama at Birmingham. Study Visits, BP Measurements, and Calculation of VVV of BP To calculate intraindividual VVV of SBP and diastolic BP (DBP), we used data from 7 follow-up visits that occurred 6, 9, 12, 16, 20, 24, and 28 months after randomization. We chose to begin the assessment period at the 6-month follow-up visit to avoid confounding by the initial reduction in BP that occurred between randomization and this visit (SBP, 6 to 10 mm Hg; DBP, approximately 5 mm Hg) due to early medication titration. To increase the precision of estimates, we calculated VVV of BP for participants with BP measurements at 5, 6, or 7 visits conducted between month 6 and 28 after randomization. The VVV of BP was imputed for participants who attended fewer than 5 visits between months 6 and 28. To maximize follow-up time, we did not extend the assessment past the 28-month follow-up visit. At each follow-up visit, BP was measured twice by a trained observer by means of a standardized technique (17). Using the average BP at each visit, we defined VVV of BP by the intraindividual SD across visits. Average real variability (ARV) and SD independent of the mean (SDIM) were calculated as alternative metrics for VVV of BP (Appendix Figure) (18). The VVV of DBP was also calculated in secondary analyses. Appendix Figure. Formulas used to calculate VVV of BP metrics. ARV = average real variability; BP = blood pressure; SDIM = SD independent of the mean; VVV = visit-to-visit variability. Outcome Ascertainment We studied 4 outcomes, including fatal CHD or nonfatal MI, all-cause mortality, stroke, and heart failure. The event ascertainment process is detailed elsewhere (14, 16). Participants were followed from the end of the assessment period to the date of each outcome, their date of death, or the end of active ALLHAT follow-up (1 October 2001 through 31 March 2002). Covariate Information Covariates used for adjustment were selected a priori on the basis of their potential role as confounders. Baseline (before randomization) variables included age, sex, race/ethnicity, education, current cigarette smoking status, body mass index, use of aspirin, high-density lipoprotein cholesterol level less than 0.91 mmol/L (<35 mg/dL) (at 2 occasions in the 5 years before ALLHAT enrollment), total cholesterol level, estimated glomerular filtration rate (eGFR), diabetes, history of MI or stroke, documentation of other atherosclerotic CVD, history of revascularization, atrial fibrillation by electrocardiography, left ventricular hypertrophy (LVH), the presence of ST depression and T-wave inversion, and use of antihypertensive medication before ALLHAT randomization. The eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation (19). Data collected at visits conducted 6 to 28 months after randomization were used to calculate mean SBP and DBP; pulse pressure; the use of antihypertensive medications beyond the randomization drug; changes in antihypertensive medication regimen (adding, stopping, or changing antihypertensive medications); use of statins; and low adherence, which is defined as a report of a participant receiving less than 80% of the randomization drug at any visit between months 6 and 28. Participants who reported taking 80% or more of their randomization drug at every visit between months 6 and 28 were considered to have high adherence. Statistical Analysis Because of limited follow-up available after the assessment period for participants randomly assigned to receive doxazosin, we restricted our analyses to the 33357 ALLHAT participants randomly assigned to receive chlorthalidone, amlodipine, or lisinopril. We excluded 7543 participants who had CVD events or died before the 28-month visit. We imputed VVV of BP for participants with fewer than 5 visits and BP measurements between months 6 and 28 of follow-up. In addition, missing data for covariates were imputed (Appendix Table 1). Imputation was performed with 10 data sets using chained equations. Appendix Table 1. Percentage of Missing Data for Participants Included in the Current Analyses Characteristics of participants included in the current analyses were calculated after participants were stratified into a quintile of SD of SBP. The KaplanMeier method was used to calculate the cumulative incidence of each outcome by quintile of SD of SBP. Cox proportional hazards regression was used to calculate multivariable-adjusted hazard ratios (HRs) for each outcome associated with a quintile of SD of SBP, with the lowest quintile serving as the reference. Four nested models were constructed. Model 1 included adjustment for age, race/ethnicity, sex, region of residence, and antihypertensive randomization assignment. Model 2 includes the variables in model 1 and additional adjustment for education, smoking status, body mass index, use of aspirin, low high-density lipoprotein cholesterol level, total cholesterol level, eGFR, diabetes, history of MI or stroke, history of other atherosclerotic CVD, history of coronary revascularization, atrial fibrillation by electrocardiography, major ST depression or T-wave inversion, LVH, use of antihypertensive medications before ALLHAT randomization, and statin use during the assessment period (months 6 through 28 of follow-up). Model 3 includes the variables in model 2 and additional adjustment for mean pulse pressure, medic

Generalizability of SPRINT Results to the U.S. Adult Population

BACKGROUND In SPRINT (Systolic Blood Pressure Intervention Trial), a systolic blood pressure (SBP) goal of <120 mm Hg resulted in lower cardiovascular disease (CVD) risk compared with an SBP goal of <140 mm Hg. OBJECTIVES The purpose of this study was to estimate the prevalence, number, and characteristics of U.S. adults meeting SPRINT eligibility criteria and determine the broader population to whom SPRINT could be generalized. METHODS We conducted a cross-sectional, population-based study using data from the National Health and Nutrition Examination Survey, 2007 to 2012. The SPRINT inclusion criteria were age ≥50 years, SBP 130 to 180 mm Hg depending on the number of antihypertensive medication classes being taken, and high CVD risk (history of coronary heart disease, estimated glomerular filtration rate of 20 to 59 ml/min/1.73 m(2), 10-year CVD risk ≥15%, or age ≥75 years). Exclusion criteria were diabetes, history of stroke, >1 g in 24 h of proteinuria daily, heart failure, estimated glomerular filtration rate <20 ml/min/1.73 m(2), or receiving dialysis. Treated hypertension was defined by self-reported use of medication to lower blood pressure with ≥1 class of antihypertensive medication identified through a pill bottle review. RESULTS Overall, 7.6% (95% confidence interval [CI]: 7.0% to 8.3%) or 16.8 million (95% CI: 15.7 to 17.8 million) U.S. adults, and 16.7% (95% CI: 15.2% to 18.3%) or 8.2 million (95% CI: 7.6 to 8.8 million) adults with treated hypertension met the SPRINT eligibility criteria. Among both the overall U.S. population and adults with treated hypertension, the percentage meeting SPRINT eligibility criteria increased with older age, was higher among males than females, and was higher among non-Hispanic whites compared with non-Hispanic blacks or Hispanics. Of U.S. adults eligible for SPRINT, 51.0% (95% CI: 47.8% to 54.1%) or 8.6 million (95% CI: 8.0 to 9.1 million) were not treated for hypertension. CONCLUSIONS A substantial percentage of U.S. adults meet the eligibility criteria for SPRINT.

Estimation of the burden of cardiovascular disease attributable to modifiable risk factors and cost-effectiveness analysis of preventative interventions to reduce this burden in Argentina

BackgroundCardiovascular disease (CVD) is the primary cause of mortality and morbidity in Argentina representing 34.2% of deaths and 12.6% of potential years of life lost (PYLL). The aim of the study was to estimate the burden of acute coronary heart disease (CHD) and stroke and the cost-effectiveness of preventative population-based and clinical interventions.MethodsAn epidemiological model was built incorporating prevalence and distribution of high blood pressure, high cholesterol, hyperglycemia, overweight and obesity, smoking, and physical inactivity, obtained from the Argentine Survey of Risk Factors dataset. Population Attributable Fraction (PAF) of each risk factor was estimated using relative risks from international sources. Total fatal and non-fatal events, PYLL and Disability Adjusted Life Years (DALY) were estimated. Costs of event were calculated from local utilization databases and expressed in international dollars (I

Cost-effectiveness analysis of a cervical cancer vaccine in five Latin American countries

). Incremental cost-effectiveness ratios (ICER) were estimated for six interventions: reducing salt in bread, mass media campaign to promote tobacco cessation, pharmacological therapy of high blood pressure, pharmacological therapy of high cholesterol, tobacco cessation therapy with bupropion, and a multidrug strategy for people with an estimated absolute risk > 20% in 10 years.ResultsAn estimated total of 611,635 DALY was lost due to acute CHD and stroke for 2005. Modifiable risk factors explained 71.1% of DALY and more than 80% of events. Two interventions were cost-saving: lowering salt intake in the population through reducing salt in bread and multidrug therapy targeted to persons with an absolute risk above 20% in 10 years; three interventions had very acceptable ICERs: drug therapy for high blood pressure in hypertensive patients not yet undergoing treatment (I

Global cardiovascular research output, citations, and collaborations: A time-trend, bibliometric analysis (1999-2008)

2,908 per DALY saved), mass media campaign to promote tobacco cessation amongst smokers (I

Association of Serum Lipids and Coronary Heart Disease in Contemporary Observational Studies

3,186 per DALY saved), and lowering cholesterol with statin drug therapy (I

Contrasting Cholesterol Management Guidelines for Adults with CKD

14,432 per DALY saved); and one intervention was not found to be cost-effective: tobacco cessation with bupropion (I

Estimación de la carga de las enfermedades cardiovasculares atribuible a factores de riesgo modificables en Argentina

59,433 per DALY saved)ConclusionsMost of the interventions selected were cost-saving or very cost-effective. This study aims to inform policy makers on resource-allocation decisions to reduce the burden of CVD in Argentina.

Adherence to High-Intensity Statins Following a Myocardial Infarction Hospitalization Among Medicare Beneficiaries

Implementation of cervical cancer (CC) vaccination in Latin America is expected to reduce the high CC burden in those countries. But the efficiency of such vaccination programs in the region still remains unknown. This study assesses the cost-effectiveness and cost-utility of introducing vaccination into the current CC disease management of five Latin American countries (Argentina, Brazil, Chile, Mexico, and Peru). The modelling results indicate that universal mass vaccination is cost-effective in the current health care setting of each country (<3x gross domestic product per capita, per country) with a substantial number of CC cases and deaths avoided in addition to an increase of quality-adjusted life years. This study will help guide the design of future clinical programmes and health-related policies. It will assist early and effective decision-making processes related to vaccine implementation in Latin America.