Marc A. Pfeffer

Bio: Marc A. Pfeffer is an academic researcher from Brigham and Women's Hospital. The author has contributed to research in topics: Heart failure & Myocardial infarction. The author has an hindex of 166, co-authored 765 publications receiving 133043 citations. Previous affiliations of Marc A. Pfeffer include Partners HealthCare & University of Miami.

Moving beyond our comfort zone

Abstract: This editorial refers to ‘Evaluation of early percutaneous coronary intervention vs. standard therapy after fibrinolysis for ST-segment elevation myocardial infarction: contribution of weighting the composite endpoint’, by J.A. Bakal et al. , doi:10.1093/eurheartj/ehs438 The randomized controlled clinical trial currently represents the gold standard by which we test whether or not a therapeutic strategy will alter a specific predefined outcome. A carefully detailed, pre-specified statistical analysis plan is established in order to test this primary hypothesis. This framework surrounding the evaluation of a trial's primary outcome is constructed to provide a level of certainty which must be achieved in order to reject the null hypothesis and declare that an observed difference between the two (or more) therapeutic strategies is not attributable to chance. As such, extensive resources (both economic and otherwise) required to conduct a clinical outcome trial are generally narrowly focused on the answer to a single clinical question, often utilizing the time to first event. We need to move beyond this current practice and use more information obtained in a trial to make more informed inferences about treatment efficacy as well as risks. When the primary endpoint is mortality and the question is precisely focused as to whether an intervention alters the patient's time to death, the current statistical framework provides a clearly understandable answer, and if the null hypothesis is rejected and the two therapies are indeed found to be different, subsequent secondary analyses are undertaken to explore the available additional clinical information further. However, unless the target patient population is limited to those with extremely poor prognosis, trials with a primary endpoint of all-cause mortality are rarely conducted. The obvious issues of giving equal weight to a fatal and non-fatal endpoint in the ‘time to first event’ approach, which ignores all events (including deaths) that occur after an …

Hyporesponsiveness to Darbepoetin Alfa in Patients With Heart Failure and Anemia in the RED-HF Study (Reduction of Events by Darbepoetin Alfa in Heart Failure) Clinical and Prognostic Associations

Abstract: Background: A poor response to erythropoiesis-stimulating agents such as darbepoetin alfa has been associated with adverse outcomes in patients with diabetes mellitus, chronic kidney disease, and anemia; whether this is also true in heart failure is unclear. Methods and Results: We performed a post hoc analysis of the RED-HF trial (Reduction of Events by Darbepoetin Alfa in Heart Failure), in which 1008 patients with systolic heart failure and anemia (hemoglobin level, 9.0–12.0 g/dL) were randomized to darbepoetin alfa. We examined the relationship between the hematopoietic response to darbepoetin alfa and the incidence of all-cause death or first heart failure hospitalization during a follow-up of 28 months. For the purposes of the present study, patients in the lowest quartile of hemoglobin change after 4 weeks were considered nonresponders. The median initial hemoglobin change in nonresponders (n=252) was −0.25 g/dL and +1.00 g/dL in the remainder of patients (n=756). Worse renal function, lower sodium levels, and less use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers were independently associated with nonresponse. Although a low endogenous erythropoietin level helped to differentiate responders from nonresponders, its predictive value in a multivariable model was poor (C statistic=0.69). Nonresponders had a higher rate of all-cause death or first heart failure hospitalization (hazard ratio, 1.25; 95% confidence interval, 1.02–1.54) and a higher risk of all-cause mortality (hazard ratio, 1.30; 95% confidence interval, 1.04–1.63) than responders. Conclusions: A poor response to darbepoetin alfa was associated with worse outcomes in heart failure patients with anemia. Patients with a poor response were difficult to identify using clinical and biochemical biomarkers. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00358215.

The decreasing incidence of left ventricular remodeling following myocardial infarction.

Abstract: Although abrupt reductions in regional contactile function (wall motion) have long been the hallmark of myocardial infarction, it has only been more recently that the long-term topographic consequences of the infarct process on the left ventricle have been appreciated. Within hours of coronary occlusion, the infarcted (non-contractile) region may thin and elongate, a process known as infarct expansion. In the ensuing weeks and months, further ventricular enlargement can occur involving both the infarcted as well as the non-infarcted myocardium a process that has been termed post-myocardial infarction ventricular remodeling. Recent increased awareness of this remodeling process and its association with impaired prognosis have been the driving force behind the evaluation and widespread adoption of therapies that have now been shown to attenuate ventricular remodeling. Yet

The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report.

Abstract: "The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure" provides a new guideline for hypertension prevention and management. The following are the key messages(1) In persons older than 50 years, systolic blood pressure (BP) of more than 140 mm Hg is a much more important cardiovascular disease (CVD) risk factor than diastolic BP; (2) The risk of CVD, beginning at 115/75 mm Hg, doubles with each increment of 20/10 mm Hg; individuals who are normotensive at 55 years of age have a 90% lifetime risk for developing hypertension; (3) Individuals with a systolic BP of 120 to 139 mm Hg or a diastolic BP of 80 to 89 mm Hg should be considered as prehypertensive and require health-promoting lifestyle modifications to prevent CVD; (4) Thiazide-type diuretics should be used in drug treatment for most patients with uncomplicated hypertension, either alone or combined with drugs from other classes. Certain high-risk conditions are compelling indications for the initial use of other antihypertensive drug classes (angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, β-blockers, calcium channel blockers); (5) Most patients with hypertension will require 2 or more antihypertensive medications to achieve goal BP (<140/90 mm Hg, or <130/80 mm Hg for patients with diabetes or chronic kidney disease); (6) If BP is more than 20/10 mm Hg above goal BP, consideration should be given to initiating therapy with 2 agents, 1 of which usually should be a thiazide-type diuretic; and (7) The most effective therapy prescribed by the most careful clinician will control hypertension only if patients are motivated. Motivation improves when patients have positive experiences with and trust in the clinician. Empathy builds trust and is a potent motivator. Finally, in presenting these guidelines, the committee recognizes that the responsible physician's judgment remains paramount.

Cochrane Handbook for Systematic Reviews of Interventions

Abstract: The Cochrane Handbook for Systematic Reviews of Interventions is the official document that describes in detail the process of preparing and maintaining Cochrane systematic reviews on the effects of healthcare interventions.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

A New Equation to Estimate Glomerular Filtration Rate

Abstract: The Modification of Diet in Renal Disease (MDRD) Study equation underestimates glomerular filtration rate (GFR) in patients with mild kidney disease. Levey and associates therefore developed and va...

Lifetime Prevalence and Age-of-Onset Distributions of DSM-IV Disorders in the National Comorbidity Survey Replication

Abstract: Context Little is known about lifetime prevalence or age of onset of DSM-IV disorders. Objective To estimate lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the recently completed National Comorbidity Survey Replication. Design and Setting Nationally representative face-to-face household survey conducted between February 2001 and April 2003 using the fully structured World Health Organization World Mental Health Survey version of the Composite International Diagnostic Interview. Participants Nine thousand two hundred eighty-two English-speaking respondents aged 18 years and older. Main Outcome Measures Lifetime DSM-IV anxiety, mood, impulse-control, and substance use disorders. Results Lifetime prevalence estimates are as follows: anxiety disorders, 28.8%; mood disorders, 20.8%; impulse-control disorders, 24.8%; substance use disorders, 14.6%; any disorder, 46.4%. Median age of onset is much earlier for anxiety (11 years) and impulse-control (11 years) disorders than for substance use (20 years) and mood (30 years) disorders. Half of all lifetime cases start by age 14 years and three fourths by age 24 years. Later onsets are mostly of comorbid conditions, with estimated lifetime risk of any disorder at age 75 years (50.8%) only slightly higher than observed lifetime prevalence (46.4%). Lifetime prevalence estimates are higher in recent cohorts than in earlier cohorts and have fairly stable intercohort differences across the life course that vary in substantively plausible ways among sociodemographic subgroups. Conclusions About half of Americans will meet the criteria for a DSM-IV disorder sometime in their life, with first onset usually in childhood or adolescence. Interventions aimed at prevention or early treatment need to focus on youth.