500 research outputs found
Recent respiratory infection and risk of venous thromboembolism: case–control study through a general practice database
Background The association between respiratory infection and risk of heart attacks and strokes is well established. However, less evidence exists for an association between respiratory infection and venous thromboembolism (VTE). In this article, we describe the associations between respiratory infection and VTE
Challenging Issues in Clinical Trial Design: Part 4 of a 4-Part Series on Statistics for Clinical Trials.
As a sequel to last week's paper on the fundamentals of clinical trial design, this paper tackles related controversial issues: noninferiority trials, the value of factorial designs, the importance and challenges of strategy trials, Data Monitoring Committees (including when to stop a trial early), and the role of adaptive designs. All topics are illustrated by relevant examples from cardiology trials
Design of Major Randomized Trials: Part 3 of a 4-Part Series on Statistics for Clinical Trials.
This paper provides practical guidance on the fundamentals of design for major randomized controlled trials. Topics covered include the choice of patients, choice of treatment and control groups, choice of primary and secondary endpoints, methods of randomization, appropriate use of blinding, and determination of trial size. Insights are made with reference to contemporary major trials in cardiology
Patterns of herpes simplex virus shedding over 1 month and the impact of acyclovir and HIV in HSV-2-seropositive women in Tanzania
Objectives Few studies have examined the frequency and duration of genital herpes simplex virus (HSV) shedding in sub-Saharan Africa. This study describes HSV shedding patterns among a sample of HSV-2-seropositive women enrolled in a placebo-controlled trial of HSV suppressive therapy (acyclovir 400 mg twice a day) in Tanzania.Methods Trial participants were invited to participate in a substudy involving 12 clinic visits over 4 weeks. At each visit, cervical, vaginal and external skin swabs were taken and analysed for HSV DNA using inhouse real-time PCR.Results HSV shedding was mainly subclinical (90%; 57/63 shedding days in the placebo arm). The most frequent shedding site was the external skin, but HSV DNA was detected from all three sites on 42% (27/63) of shedding days. In HIV-negative women, HSV DNA was detected on 3% (9/275) of days in the acyclovir versus 11% (33/309) in the placebo arm, while in HIV-positive women, detection was on 14% (23/160) versus 19% (30/155) of days, respectively.Conclusions HSV shedding was common, varying greatly by individual. Shedding rates were similar to studies in African and non-African settings. Among HIV-negative women, shedding rates were lower in the acyclovir arm; however, acyclovir did not substantially impact on HSV shedding in HIV-positive women
Effect of oxandrolone and timing of pubertal induction on final height in Turner’s syndrome: randomised, double blind, placebo controlled trial
Objective To examine the effect of oxandrolone and the timing of pubertal induction on final height in girls with Turner’s syndrome receiving a standard dose of growth hormone
Impact of call-to-balloon time on 30-day mortality in contemporary practice.
OBJECTIVE: Studies reporting an association between treatment delay and outcome for patients with ST segment elevation myocardial infarction (STEMI) have generally not included patients treated by a primary percutaneous coronary intervention (PPCI) service that systematically delivers reperfusion therapy to all eligible patients. We set out to determine the association of call-to-balloon (CTB) time with 30-day mortality after PPCI in a contemporary series of patients treated within a national reperfusion service. METHODS: We analysed data on 16 907 consecutive patients with STEMI treated by PPCI in England and Wales in 2011 with CTB time of ≤6 hours. RESULTS: The median CTB and door-to-balloon times were 111 and 41 min, respectively, with 80.9% of patients treated within 150 min of the call for help. An out-of-hours call time (58.2% of patients) was associated with a 10 min increase in CTB time, whereas inter-hospital transfer for PPCI (18.5% of patients) was associated with a 49 min increase in CTB time. CTB time was independently associated with 30-day mortality (p180-240 min compared with ≤90 min. The relationship between CTB time and 30-day mortality was influenced by patient risk profile with a greater absolute impact of increasing CTB time on mortality in high-risk patients. CONCLUSION: CTB time is a useful metric to assess the overall performance of a PPCI service. Delays to reperfusion remain important even in the era of organised national PPCI services with rapid treatment times and efforts should continue to minimise treatment delays
The effect of age on outcomes of coronary artery bypass surgery compared with balloon angioplasty or bare-metal stent implantation among patients with multivessel coronary disease. A collaborative analysis of individual patient data from 10 randomized trials.
OBJECTIVES: This study sought to assess whether patient age modifies the comparative effectiveness of coronary artery bypass graft (CABG) surgery and percutaneous coronary intervention (PCI). BACKGROUND: Increasingly, CABG and PCI are performed in older patients to treat multivessel disease, but their comparative effectiveness is uncertain. METHODS: Individual data from 7,812 patients randomized in 1 of 10 clinical trials of CABG or PCI were pooled. Age was analyzed as a continuous variable in the primary analysis and was divided into tertiles for descriptive purposes (≤56.2 years, 56.3 to 65.1 years, ≥65.2 years). The outcomes assessed were death, myocardial infarction and repeat revascularization over complete follow-up, and angina at 1 year. RESULTS: Older patients were more likely to have hypertension, diabetes, and 3-vessel disease compared with younger patients (p < 0.001 for trend). Over a median follow-up of 5.9 years, the effect of CABG versus PCI on mortality varied according to age (interaction p < 0.01), with adjusted CABG-to-PCI hazard ratios and 95% confidence intervals (CI) of 1.23 (95% CI: 0.95 to 1.59) in the youngest tertile; 0.89 (95% CI: 0.73 to 1.10) in the middle tertile; and 0.79 (95% CI: 0.67 to 0.94) in the oldest tertile. The CABG-to-PCI hazard ratio of less than 1 for patients 59 years of age and older. A similar interaction of age with treatment was present for the composite outcome of death or myocardial infarction. In contrast, patient age did not alter the comparative effectiveness of CABG and PCI on the outcomes of repeat revascularization or angina. CONCLUSIONS: Patient age modifies the comparative effectiveness of CABG and PCI on hard cardiac events, with CABG favored at older ages and PCI favored at younger ages
Massive-Star Supernovae as Major Dust Factories
We present late-time optical and mid-infrared observations of the Type-II
supernova 2003gd in NGC 628. Mid-infrared excesses consistent with cooling dust
in the ejecta are observed 499-678 days after outburst, and are accompanied by
increasing optical extinction and growing asymmetries in the emission-line
profiles. Radiative-transfer models show that up to 0.02 solar masses of dust
has formed within the ejecta, beginning as early as 250 days after outburst.
These observations show that dust formation in supernova ejecta can be
efficient and that massive-star supernovae can be major dust producers
throughout the history of the Universe.Comment: 11 pages, 1 figure. Accepted 2006 May 30 for publication in Science;
Published in 2006 Jun 8 edition of Science Express; 2nd version fixes minor
change in conclusion made in pres
Bluebelle study (phase A):a mixed-methods feasibility study to inform an RCT of surgical wound dressing strategies
Percutaneous Revascularization for Ischemic Ventricular Dysfunction : Rationale and Design of the REVIVED-BCIS2 Trial: Percutaneous Coronary Intervention for Ischemic Cardiomyopathy
OBJECTIVES: Evaluate whether PCI in combination with optimal medical therapy (OMT) will reduce all-cause death and hospitalization for HF compared to a strategy of OMT alone. BACKGROUND: Ischemic cardiomyopathy (ICM) is the most common cause of heart failure (HF) and is associated with significant mortality and morbidity. Surgical revascularization has been shown to improve long-term outcomes in some patients, but surgery itself carries a major early hazard. Percutaneous coronary intervention (PCI) may allow a better balance between risk and benefit. METHODS: REVIVED-BCIS2 is a prospective, multi-center, open-label, randomized controlled trial, funded by the National Institute for Health Research in the United Kingdom. Follow-up will be for at least 2 years from randomization. Secondary outcomes include left ventricular ejection fraction (LVEF), quality of life scores, appropriate implantable cardioverter defibrillator therapy and acute myocardial infarction. Patients with LVEF ≤35%, extensive coronary disease and demonstrable myocardial viability are eligible for inclusion and those with a myocardial infarction within 4 weeks, decompensated HF or sustained ventricular arrhythmias within 72 h are excluded. A trial of 700 patients has more than 85% power to detect a 30% relative reduction in hazard. RESULTS: A total of 400 patients have been enrolled to date. CONCLUSIONS: International guidelines do not provide firm recommendations on the role of PCI in managing severe ICM, because of a lack of robust evidence. REVIVED-BCIS2 will provide the first randomized data on the efficacy and safety of PCI in ICM and has the potential to inform guidelines pertaining to both revascularization and HF. (Study of Efficacy and Safety of Percutaneous Coronary Intervention to Improve Survival in Heart Failure [REVIVED-BCIS2]; NCT01920048) (REVascularisation for Ischaemic VEntricular Dysfunction; ISRCTN45979711)
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