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Biomedical subjects

Charles H Hennekens

Publications and source records attributed to Charles H Hennekens.

At least 19 recordsLinked to original sources
PubMed2006

Aspirin and decreased adult-onset asthma: randomized comparisons from the physicians' health study.

RATIONALE: In an observational cohort study, women who self-selected for frequent aspirin use developed less newly diagnosed asthma than women who did not take aspirin. OBJECTIVE: To explore whether low-dose aspirin decreased the risk of newly diagnosed asthma in a randomized, double-blind, placebo-controlled trial. METHODS: The Physicians' Health Study randomized 22,071 apparently healthy male physicians, aged 40-84 yr at baseline and tolerant of aspirin, over an 18-wk run-in period, to 325 mg aspirin or placebo on alternate days. The aspirin component was terminated after 4.9 yr due principally to the emergence of a statistically extreme 44% reduction in risk of first myocardial infarction among those randomly assigned to aspirin. MEASUREMENTS: Physicians could self-report an asthma diagnosis on questionnaires at baseline, 6 mo, and annually thereafter. Asthma was not an a priori endpoint of the trial. RESULTS: Among 22,040 physicians without reported asthma at randomization, there were 113 new asthma diagnoses in the aspirin group and 145 in the placebo group. The hazard ratio was 0.78 (95% confidence interval, 0.61-1.00; p = 0.045). This apparent 22% lower risk of newly diagnosed asthma among those assigned to aspirin was not modified by baseline characteristics including smoking, body mass index, or age. CONCLUSIONS: Aspirin reduced the risk of newly diagnosed adult-onset asthma in a large, randomized clinical trial of apparently healthy, aspirin-tolerant men. This result requires replication in randomized trials designed a priori to test this hypothesis; it does not imply that aspirin improves symptoms in patients with asthma.

Adult↗
PubMed2006

Effect of statins on platelet PAR-1 thrombin receptor in patients with the metabolic syndrome (from the PAR-1 inhibition by statins [PARIS] study).

We investigated whether, in primary prevention patients with metabolic syndrome, statins affect the platelet protease-activated receptor-1 (PAR-1) thrombin receptor by performing serial measurements of its activity and the antigen expression level by flow cytometry before and during treatment. Recent data from randomized trials of statins are compatible with the possibility of clinically relevant pleiotropic effects. The use of statins is associated with a reduced thrombosis burden and diminished platelet activity, as shown in animal models and in vitro studies. Seventy patients with the metabolic syndrome who were not taking antiplatelet agents were assigned consecutively at starting doses at the discretion of the responsible clinician to 1 of 6 statins (atorvastatin, fluvastatin, lovastatin, pravastatin, rosuvastatin, or simvastatin) or to a no-statin group for 6 weeks. Platelet expression of intact (SPAN12 antibody) and cleaved (WEDE15) PAR-1 thrombin receptors were assessed by flow cytometry at baseline and at weeks 4 and 6 of treatment. At baseline, no difference was found in receptor expression. However, after 4 weeks of treatment, all statins had significantly inhibited (46% to 55%) the activated epitope of PAR-1 expression. After 6 weeks, inhibition remained, despite a slight rebound (22% to 37%). Also, a delayed pattern of inhibition of the intact PAR-1 receptor epitope was found. In conclusion, all statins inhibited the activity and antigen level of the platelet PAR-1 thrombin receptor, which has a major role in regulating platelet activity and thrombin formation. These observational data offer a plausible mechanism for the recently demonstrated pleiotropic effects of statins that may contribute to early clinical benefit.

Blood Platelets↗
PubMed2006

Update for primary healthcare providers: recent statin trials and revised National Cholesterol Education Program III guidelines.

Statins produce large, clinically important beneficial effects on total low-density lipoprotein (LDL) cholesterol and triglycerides while raising high-density lipoprotein (HDL) cholesterol--each of which increases the risks for cardiovascular disease (CVD). In randomized trials of secondary and primary prevention, and their meta-analyses, statins confer statistically significant, clinically important reductions in myocardial infarction, stroke, and CVD death. In 2001, the National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III included LDL as the primary target, recommending optional goals of < 100 mg/dL for high-risk patients, < 130 mg/dL for moderate-risk patients, and < 160 mg/dL for low-risk patients. We conducted a search of randomized trials of statins whose results were published since May 15, 2001. We extracted overall trial results and data on adverse events, when available. We reviewed 7 published trials of statins, some of which contributed to the recent addendum to the NCEP ATP III guidelines that recommend reducing LDL goals to < 70 for very high-risk and < 100 for moderately high-risk patients via statins. Data from these trials demonstrate that greater LDL reductions produce larger CVD benefits in various categories of high- and moderate-risk patients, including a large number of primary prevention patients with metabolic syndrome who should be treated as aggressively as patients who have survived a myocardial infarction or stroke. Together, these recent statin trials and the NCEP ATP III revised guidelines, if implemented by primary healthcare providers, would result in many more patients receiving statins of proven benefit and reassuring adverse event profile.

Cardiovascular Diseases↗
PubMed2006

N-acetylcysteine and contrast-induced nephropathy: a meta-analysis of 13 randomized trials.

BACKGROUND: Contrast-induced nephropathy (CIN) following coronary angiography increases morbidity and mortality. Randomized trials of small sample size have evaluated whether N-acetylcysteine (NAC) prevents CIN in patients with renal dysfunction. METHODS: To conduct a meta-analysis of the randomized trials the following databases were searched: MEDLINE (1966-2003), Cochrane Controlled Trials Register, ACP Journal Club online, published abstracts presented at the major cardiology and nephrology meetings, references from reviews. Two authors independently evaluated all relevant randomized trials. Eligibility criteria were (1) randomized placebo controlled trials of NAC, (2) patients with impaired renal function (creatinine >1.2 mg/dL) undergoing coronary angiography, (3) patients receiving intravenous fluids and low-osmolarity nonionic contrast media, (4) the primary outcome was CIN (increases in creatinine of either at least 0.5 mg/dL or 25% from baseline to 48 hours). Of 589 trials reviewed 3 disagreements were easily resolved by mutual discussion and 13 were selected. Data extraction included patient characteristics, intravenous fluid regimen, type and dose of contrast media, dosing regimen, creatinine at baseline and 48 hours and CIN requiring dialysis. RESULTS: Four of the 13 trials reported statistically significant results. In meta-analysis of the 13 trials, which included 1892 patients, the RR was 0.68 (95%CI, 0.46-1.01). The addition of the trial of patients undergoing computerized tomography, which had formulated the hypothesis, yielded a statistically significant reduction (RR 0.64 [95%CI 0.42-0.96]) as did an earlier meta-analysis of 7 trials. CONCLUSIONS: Our meta-analysis of the most currently available randomized data concerning NAC before coronary angiography to prevent CIN in patients with impaired renal function is neither conclusive nor provides proof beyond a reasonable doubt to influence clinical practice and public policy. The intervention has minimal toxicity but the width of the 95% CI remains compatible with a range from a large benefit to none at all. In addition, the trials used change in creatinine as the measure of outcome. Further randomized trials of large sample size and with clinical outcomes will add importantly relevant information to the totality of evidence and allow the most rational clinical decisions for individual patients as well as policy decisions for the health of the general public.

Acetylcysteine↗
PubMed2006

Valsartan inhibits platelet activity at different doses in mild to moderate hypertensives: Valsartan Inhibits Platelets (VIP) trial.

BACKGROUND: Previous in vitro studies have suggested that valsartan produces significant inhibition of human platelets, probably targeting angiotensin I platelet receptors. To test whether valsartan inhibits platelet activity in mild to moderate hypertensives we conducted the randomized Valsartan Inhibits Platelets (VIP) trial. METHODS AND RESULTS: Seventy-five patients with mild to moderate hypertension were randomized to valsartan 80 (n = 25), valsartan 160 (n = 29), or valsartan 320 mg/d (n = 21) for 9 weeks. Platelet function was assessed at baseline, week 5, and week 9 by aggregometry, flow cytometry, and cartridge-based analyzer. Independently of dose and duration, valsartan provided early sustained significant inhibition of adenosine diphosphate-induced platelet aggregation, decreased shear-induced activation measured with PFA-100 analyzer, and diminished expression of GP IIb/IIIa activity measured by PAC-1 antibody, GPIb (CD42b), vitronectin receptor (CD51/61), P-selectin (CD62p), lysosome-associated membrane protein (CD107a), and CD40-ligand (CD154). The antiplatelet properties of valsartan were more profound in patients with diabetes (n = 28) when compared with the nondiabetic group (n = 47). In subgroup analyses of patients with diabetes there appeared to be stronger inhibition of the platelet receptors, a significant decrease of adenosine diphosphate- and collagen-induced platelet aggregation, and more profound inhibition of GP IIb/IIIa activity. CONCLUSIONS: In the randomized VIP trial, valsartan produced sustained inhibition of platelet aggregation and major platelet receptors. The antiplatelet properties of valsartan were not dose or time dependent. In subgroup analyses patients with diabetes with mild to moderate hypertension tended to have greater platelet inhibition, a finding which, if confirmed in future studies suggests possible additional advantages for using valsartan in this high-risk population.

Aged↗
PubMed2006

Lack of deleterious interaction between angiotensin receptor blockers and beta-blockers in the treatment of patients with heart failure.

The Valsartan-Heart Failure trial formulated the hypothesis that combination therapy with angiotensin-converting enzyme inhibitors and beta-blockers with an angiotensin-receptor blocker had a deleterious interaction. Furthermore, the Food and Drug Administration (FDA)-approved heart failure indication for valsartan included the statement that concomitant use of an angiotensin-converting enzyme inhibitor, a beta-blocker was not recommended. The Candesartan in Heart Failure Assessment of Reduction in Mortality and Morbidity (CHARM)-Added and the VALsartan In Acute Myocardial Infarction Trial (VALIANT) provide reassuring evidence to support concomitant use of angiotensin-receptor blockers, angiotensin-converting enzyme inhibitors, and beta-blockers. The FDA-approved heart failure indication for candesartan included the statement of additive benefits with angiotensin-converting enzyme inhibitors and beta-blockers and led to a change in the valsartan label. These considerations have great clinical and public health importance given the increasing numbers of patients with heart failure, their high morbidity and mortality, and the relatively limited number of effective drug therapies.

Adrenergic beta-Antagonists↗
PubMed2006

Dose of aspirin in the treatment and prevention of cardiovascular disease: current and future directions.

In meta-analyses of randomized trials of aspirin among patients with prior occlusive vascular disease events (secondary prevention), doses from 75 mg to more than 1500 mg daily provide similar benefits on myocardial infarction, stroke, and cardiovascular death. In acute myocardial infarction and during acute occlusive stroke, a loading dose of 162.5 to 325 mg is necessary to achieve a rapid clinical antithrombotic effect. In primary prevention trials, predominantly among men, aspirin (75 mg daily to 325 mg on alternate days) reduced the risk of a first myocardial infarction. In a large-scale trial in women, aspirin (100 mg on alternate days) reduced risk of a first stroke. In subgroup analyses of women older than age 65, aspirin significantly reduced first myocardial infarction and ischemic stroke. Direct comparisons of higher doses may yield additional cardiovascular benefits. At present, daily doses of 75 to 325 mg aspirin are sufficient for long-term treatment and prevention of cardiovascular disease.

Aspirin↗
PubMed2006

Evolving perspectives on clopidogrel in the treatment of ischemic stroke.

Antiplatelet therapy is indicated for the treatment of ischemic stroke or transient ischemic attack (TIA). Aspirin reduces subsequent occlusive vascular events, including recurrent stroke, by about 25%. In such patients, clopidogrel has been evaluated in an effort to further reduce risk. In the Management of Atherothrombosis with Clopidogrel in High-risk Patients trial, the combination of clopidogrel plus aspirin was compared with clopidogrel alone, and the Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance trial tested the addition of clopidogrel to aspirin. Combination therapy with aspirin plus clopidogrel provided no significant incremental benefit compared with aspirin or clopidogrel alone. In addition, combination therapy increased the risk of serious bleeding. On the basis of the current totality of evidence for long-term treatment of survivors of ischemic stroke or TIA, clopidogrel is an effective alternative for patients who are intolerant to aspirin.

Aspirin↗
PubMed2006

High-risk African Americans with multiple risk factors for cardiovascular disease: challenges in prevention, diagnosis, and treatment.

Coronary heart disease (CHD) is the second leading cause of death in the United States. Despite previous downward trends, which have not persisted, CHD mortality remains higher in African Americans than in Whites. Among African American and White adolescents and adults are trends of increased physical inactivity, smoking, and obesity. Approximately 47 million Americans have metabolic syndrome, a constellation of obesity, hypertension, dyslipidemia, and insulin resistance leading to diabetes. Despite a lower prevalence of metabolic syndrome, African Americans are more insulin resistant than Whites at similar degrees of adiposity, have higher blood pressures, and among women, have more obesity. Since African Americans tend to be diagnosed later and have more risk factors, which confers greater than additive risks, we propose the term "African American multiple-risk patient (AAMRP)." The AAMRP poses clinical and public health challenges for healthcare providers. We provide clinical and public health strategies for early detection and aggressive management of AAMRP.

Black or African American↗
PubMed2005

Phenylpropanolamine and hemorrhagic stroke in the Hemorrhagic Stroke Project: a reappraisal in the context of science, the Food and Drug Administration, and the law.

The report of the Hemorrhagic Stroke Project (HSP), a case-control study of phenylpropanolamine (PPA) was the primary reason that the US Food and Drug Administration (FDA) requested that PPA-containing products voluntarily be withdrawn from the market. In subsequent litigation, scientific information emerged that was not available during the deliberations of the FDA and its advisory committee. Our reappraisal leads us to conclude that chance, bias, and confounding are plausible alternative explanations for the observed findings. Thus, we believe that it is not possible to conclude that there is any valid statistical association between PPA and hemorrhagic stroke, let alone make any judgment of causality. Our reappraisal suggests the FDA's regulatory request may have been premature.

Adolescent↗
PubMed2005

Analgesic use and risk of subsequent hypertension in apparently healthy men.

BACKGROUND: Prospective studies have suggested that women who self-select for use of analgesics have an increased risk of hypertension, but data in men are sparse. We tested whether apparently healthy male physicians who reported analgesic use had an increased risk of subsequent hypertension. METHODS: Prospective cohort study of 8229 participants in the Physicians' Health Study who were free of hypertension and completed detailed analgesic questionnaires. Hypertension was defined as self-reported blood pressure of 140/90 mm Hg or higher or use of antihypertensive medication. RESULTS: After a mean of 5.8 years' follow-up, 2234 men (27.2%) reported subsequent hypertension. We categorized the cumulative analgesic use in quintiles. After adjusting for potential confounders, men in the highest quintile had no statistically significant increased risk of hypertension (hazard ratio, 1.12; 95% confidence interval, 0.97-1.31) when compared with those in the lowest quintile. In subgroup analyses, we evaluated the cumulative use of nonsteroidal anti-inflammatory drugs, acetaminophen, and aspirin. Compared with never users, men who reported consuming at least 2500 pills had hazard ratios of 1.05 (95% confidence interval, 0.89-1.24) for nonsteroidal anti-inflammatory drugs, 1.08 (95% confidence interval, 0.87-1.34) for acetaminophen, and 1.16 (95% confidence interval, 0.92-1.48) for aspirin. The results were similar for analgesic use in the year preceding the analgesic questionnaire. CONCLUSION: In this large cohort, apparently healthy male physicians who self-selected for analgesic use had no significantly increased risk of subsequent hypertension, although a small to moderately increased risk cannot be excluded in observational studies.

Acetaminophen↗
PubMed2005

Low-dose aspirin in the primary prevention of cancer: the Women's Health Study: a randomized controlled trial.

CONTEXT: Basic research and observational evidence as well as results from trials of colon polyp recurrence suggest a role for aspirin in the chemoprevention of cancer. OBJECTIVE: To examine the effect of aspirin on the risk of cancer among healthy women. DESIGN, SETTING, AND PARTICIPANTS: In the Women's Health Study, a randomized 2 x 2 factorial trial of aspirin and vitamin E conducted between September 1992 and March 2004, 39 876 US women aged at least 45 years and initially without previous history of cancer, cardiovascular disease, or other major chronic illness were randomly assigned to receive either aspirin or aspirin placebo and followed up for an average of 10.1 years. INTERVENTION: A dose of 100 mg of aspirin (n=19 934) or aspirin placebo (n=19 942) administered every other day. MAIN OUTCOME MEASURES: Confirmed newly diagnosed invasive cancer at any site, except for nonmelanoma skin cancer. Incidence of breast, colorectal, and lung cancer were secondary end points. RESULTS: No effect of aspirin was observed on total cancer (n = 2865; relative risk [RR], 1.01; 95% confidence interval [CI], 0.94-1.08; P = .87), breast cancer (n = 1230; RR, 0.98; 95% CI, 0.87-1.09; P = .68), colorectal cancer (n = 269; RR, 0.97; 95% CI, 0.77-1.24; P = .83), or cancer of any other site, with the exception of lung cancer for which there was a trend toward reduction in risk (n = 205; RR, 0.78; 95% CI, 0.59-1.03; P = .08). There was also no reduction in cancer mortality either overall (n = 583; RR, 0.95; 95% CI, 0.81-1.11; P = .51) or by site, except for lung cancer mortality (n = 140; RR, 0.70; 95% CI, 0.50-0.99; P = .04). No evidence of differential effects of aspirin by follow-up time or interaction with vitamin E was found. CONCLUSIONS: Results from this large-scale, long-term trial suggest that alternate day use of low-dose aspirin (100 mg) for an average 10 years of treatment does not lower risk of total, breast, colorectal, or other site-specific cancers. A protective effect on lung cancer or a benefit of higher doses of aspirin cannot be ruled out.

Aspirin↗
PubMed2005

Vitamin E in the primary prevention of cardiovascular disease and cancer: the Women's Health Study: a randomized controlled trial.

CONTEXT: Basic research provides plausible mechanisms and observational studies suggest that apparently healthy persons, who self-select for high intakes of vitamin E through diet or supplements, have decreased risks of cardiovascular disease and cancer. Randomized trials do not generally support benefits of vitamin E, but there are few trials of long duration among initially healthy persons. OBJECTIVE: To test whether vitamin E supplementation decreases risks of cardiovascular disease and cancer among healthy women. DESIGN, SETTING, AND PARTICIPANTS: In the Women's Health Study conducted between 1992 and 2004, 39 876 apparently healthy US women aged at least 45 years were randomly assigned to receive vitamin E or placebo and aspirin or placebo, using a 2 x 2 factorial design, and were followed up for an average of 10.1 years. INTERVENTION: Administration of 600 IU of natural-source vitamin E on alternate days. MAIN OUTCOME MEASURES: Primary outcomes were a composite end point of first major cardiovascular event (nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death) and total invasive cancer. RESULTS: During follow-up, there were 482 major cardiovascular events in the vitamin E group and 517 in the placebo group, a nonsignificant 7% risk reduction (relative risk [RR], 0.93; 95% confidence interval [CI], 0.82-1.05; P = .26). There were no significant effects on the incidences of myocardial infarction (RR, 1.01; 95% CI, 0.82-1.23; P = .96) or stroke (RR, 0.98; 95% CI, 0.82-1.17; P = .82), as well as ischemic or hemorrhagic stroke. For cardiovascular death, there was a significant 24% reduction (RR, 0.76; 95% CI, 0.59-0.98; P = .03). There was no significant effect on the incidences of total cancer (1437 cases in the vitamin E group and 1428 in the placebo group; RR, 1.01; 95% CI, 0.94-1.08; P = .87) or breast (RR, 1.00; 95% CI, 0.90-1.12; P = .95), lung (RR, 1.09; 95% CI, 0.83-1.44; P = .52), or colon cancers (RR, 1.00; 95% CI, 0.77-1.31; P = .99). Cancer deaths also did not differ significantly between groups. There was no significant effect of vitamin E on total mortality (636 in the vitamin E group and 615 in the placebo group; RR, 1.04; 95% CI, 0.93-1.16; P = .53). CONCLUSIONS: The data from this large trial indicated that 600 IU of natural-source vitamin E taken every other day provided no overall benefit for major cardiovascular events or cancer, did not affect total mortality, and decreased cardiovascular mortality in healthy women. These data do not support recommending vitamin E supplementation for cardiovascular disease or cancer prevention among healthy women.

Aged↗
PubMed2005

A randomized trial of low-dose aspirin in the primary prevention of cardiovascular disease in women.

BACKGROUND: Randomized trials have shown that low-dose aspirin decreases the risk of a first myocardial infarction in men, with little effect on the risk of ischemic stroke. There are few similar data in women. METHODS: We randomly assigned 39,876 initially healthy women 45 years of age or older to receive 100 mg of aspirin on alternate days or placebo and then monitored them for 10 years for a first major cardiovascular event (i.e., nonfatal myocardial infarction, nonfatal stroke, or death from cardiovascular causes). RESULTS: During follow-up, 477 major cardiovascular events were confirmed in the aspirin group, as compared with 522 in the placebo group, for a nonsignificant reduction in risk with aspirin of 9 percent (relative risk, 0.91; 95 percent confidence interval, 0.80 to 1.03; P=0.13). With regard to individual end points, there was a 17 percent reduction in the risk of stroke in the aspirin group, as compared with the placebo group (relative risk, 0.83; 95 percent confidence interval, 0.69 to 0.99; P=0.04), owing to a 24 percent reduction in the risk of ischemic stroke (relative risk, 0.76; 95 percent confidence interval, 0.63 to 0.93; P=0.009) and a nonsignificant increase in the risk of hemorrhagic stroke (relative risk, 1.24; 95 percent confidence interval, 0.82 to 1.87; P=0.31). As compared with placebo, aspirin had no significant effect on the risk of fatal or nonfatal myocardial infarction (relative risk, 1.02; 95 percent confidence interval, 0.84 to 1.25; P=0.83) or death from cardiovascular causes (relative risk, 0.95; 95 percent confidence interval, 0.74 to 1.22; P=0.68). Gastrointestinal bleeding requiring transfusion was more frequent in the aspirin group than in the placebo group (relative risk, 1.40; 95 percent confidence interval, 1.07 to 1.83; P=0.02). Subgroup analyses showed that aspirin significantly reduced the risk of major cardiovascular events, ischemic stroke, and myocardial infarction among women 65 years of age or older. CONCLUSIONS: In this large, primary-prevention trial among women, aspirin lowered the risk of stroke without affecting the risk of myocardial infarction or death from cardiovascular causes, leading to a nonsignificant finding with respect to the primary end point.

Age Factors↗
PubMed2005

The data monitoring experience in the Candesartan in Heart Failure Assessment of Reduction in Mortality and morbidity (CHARM) program.

BACKGROUND: The CHARM program was designed as 3 separate randomized trials comparing candesartan with placebo in patients with chronic heart failure (CHF) who (1) were intolerant to angiotensin-converting enzyme inhibitor and had left ventricular ejection fraction (LVEF) < or =0.40; (2) were on angiotensin-converting enzyme inhibitor and had LVEF < or =0.40; or (3) had LVEF >0.40. CHARM provides an interesting example of the challenges faced by a Data and Safety Monitoring Committee (DSMC). METHODS: Although the primary efficacy end point for each component trial was cardiovascular (CV) death or hospitalization for CHF, the primary outcome for the overall program was all-cause mortality. The DSMC received monthly safety reports and also met every 6 months (7 times in all) to review interim reports. Statistical stopping guidelines were predefined for all-cause mortality in the overall program. The overarching principle of the DSMC was proof beyond a reasonable doubt that would be likely to influence clinical practice. RESULTS: There were significant treatment differences in all-cause mortality for the overall program at several interim analyses, and the statistical stopping guideline was reached on one occasion. However, even a conventional level of statistical significance (P < .050) was achieved in only 1 of the 3 component trials. The DSMC consistently recommended that the program continue as planned. The final published result for all-cause death over a median of 3.1 years was a 9% reduction in hazard (95% CI 0%-17%, P = .055), whereas for CV death or hospitalization for CHF, there was a 16% reduction in hazard (95% CI 9%-23%, P < .0001). Subsequent exploratory analyses suggest that the hazard reduction in CV death was more marked in the first year after randomization and that, if real, this apparent treatment-time interaction offers a plausible explanation for why the interim mortality data showed statistically more extreme findings than the overall final results. CONCLUSION: The DSMC experience in the CHARM program illustrates the importance of continuing a trial to its scheduled completion unless there is proof beyond a reasonable doubt that would influence clinical practice rather than strict reliance on a statistical stopping guideline.

Angiotensin II Type 1 Receptor Blockers↗