403 resultados para Randomization
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BACKGROUND The role of fibrinolytic therapy in patients with intermediate-risk pulmonary embolism is controversial. METHODS In a randomized, double-blind trial, we compared tenecteplase plus heparin with placebo plus heparin in normotensive patients with intermediate-risk pulmonary embolism. Eligible patients had right ventricular dysfunction on echocardiography or computed tomography, as well as myocardial injury as indicated by a positive test for cardiac troponin I or troponin T. The primary outcome was death or hemodynamic decompensation (or collapse) within 7 days after randomization. The main safety outcomes were major extracranial bleeding and ischemic or hemorrhagic stroke within 7 days after randomization. RESULTS Of 1006 patients who underwent randomization, 1005 were included in the intention-to-treat analysis. Death or hemodynamic decompensation occurred in 13 of 506 patients (2.6%) in the tenecteplase group as compared with 28 of 499 (5.6%) in the placebo group (odds ratio, 0.44; 95% confidence interval, 0.23 to 0.87; P=0.02). Between randomization and day 7, a total of 6 patients (1.2%) in the tenecteplase group and 9 (1.8%) in the placebo group died (P=0.42). Extracranial bleeding occurred in 32 patients (6.3%) in the tenecteplase group and 6 patients (1.2%) in the placebo group (P<0.001). Stroke occurred in 12 patients (2.4%) in the tenecteplase group and was hemorrhagic in 10 patients; 1 patient (0.2%) in the placebo group had a stroke, which was hemorrhagic (P=0.003). By day 30, a total of 12 patients (2.4%) in the tenecteplase group and 16 patients (3.2%) in the placebo group had died (P=0.42). CONCLUSIONS In patients with intermediate-risk pulmonary embolism, fibrinolytic therapy prevented hemodynamic decompensation but increased the risk of major hemorrhage and stroke. (Funded by the Programme Hospitalier de Recherche Clinique in France and others; PEITHO EudraCT number, 2006-005328-18; ClinicalTrials.gov number, NCT00639743.).
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Historical information is always relevant for clinical trial design. Additionally, if incorporated in the analysis of a new trial, historical data allow to reduce the number of subjects. This decreases costs and trial duration, facilitates recruitment, and may be more ethical. Yet, under prior-data conflict, a too optimistic use of historical data may be inappropriate. We address this challenge by deriving a Bayesian meta-analytic-predictive prior from historical data, which is then combined with the new data. This prospective approach is equivalent to a meta-analytic-combined analysis of historical and new data if parameters are exchangeable across trials. The prospective Bayesian version requires a good approximation of the meta-analytic-predictive prior, which is not available analytically. We propose two- or three-component mixtures of standard priors, which allow for good approximations and, for the one-parameter exponential family, straightforward posterior calculations. Moreover, since one of the mixture components is usually vague, mixture priors will often be heavy-tailed and therefore robust. Further robustness and a more rapid reaction to prior-data conflicts can be achieved by adding an extra weakly-informative mixture component. Use of historical prior information is particularly attractive for adaptive trials, as the randomization ratio can then be changed in case of prior-data conflict. Both frequentist operating characteristics and posterior summaries for various data scenarios show that these designs have desirable properties. We illustrate the methodology for a phase II proof-of-concept trial with historical controls from four studies. Robust meta-analytic-predictive priors alleviate prior-data conflicts ' they should encourage better and more frequent use of historical data in clinical trials.
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AIM Abstracts of randomized clinical trials are extremely important as trial appraisal is often based on the information included here. The objective of this study was to assess the quality of the reporting of RCT abstracts in journals of Oral Implantology. MATERIAL AND METHODS Six leading Implantology journals were screened for RCTs between years 2008 and 2012. A 21-item modified CONSORT for abstracts checklist was used to examine the completeness of abstract reporting. Descriptive statistics and linear regression modeling were employed for data analysis. RESULTS One hundred and sixty three RCT abstracts were included in this study. The majority of the RCTs were published in the Clinical Oral Implants Research (42.9%). The mean overall reporting quality score was 58.6% (95% CI: 57.6-59.7). The highest score was noted in the European Journal of Oral Implantology (63.8%; 95% CI: 61.8-65.8). Multivariate analysis demonstrated that abstract quality score was related to publication journal and number of research centers involved. Most abstracts adequately reported interventions (89.0%), objectives (77.9%) and conclusions (74.8%) while failed to report randomization procedures, allocation concealment, effect estimate, confidence intervals, and funding. Registration of RCTs was not reported in any of the abstracts. CONCLUSIONS The reporting quality in abstracts of RCTs published in Oral Implantology journals needs to be improved. Editors and authors should be encouraged to endorse the CONSORT for abstracts guidelines in order to achieve optimal quality in abstract reporting.
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INTRODUCTION Recent meta-analyses of the outcome of apical surgery using modern techniques including microsurgical principles and high-power magnification have yielded higher rates of healing. However, the information is mainly based on 1- to 2-year follow-up data. The present prospective study was designed to re-examine a large sample of teeth treated with apical surgery after 5 years. METHODS Patients were recalled 5 years after apical surgery, and treated teeth were classified as healed or not healed based on clinical and radiographic examination. (The latter was performed independently by 3 observers). Two different methods of root-end preparation and filling (primary study parameters) were to be compared (mineral trioxide aggregate [MTA] vs adhesive resin composite [COMP]) without randomization. RESULTS A total of 271 patients and teeth from a 1-year follow-up sample of 339 could be re-examined after 5 years (dropout rate = 20.1%). The overall rate of healed cases was 84.5% with a significant difference (P = .0003) when comparing MTA (92.5%) and COMP (76.6%). The evaluation of secondary study parameters yielded no significant difference for healing outcome when comparing subcategories (ie, sex, age, type of tooth treated, post/screw, type of surgery). CONCLUSIONS The results from this prospective nonrandomized clinical study with a 5-year follow-up of 271 teeth indicate that MTA exhibited a higher healing rate than COMP in the longitudinal prognosis of root-end sealing.
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Bei EKP-Experimenten ist oft nicht von vornherein klar, in welchen Zeitfenstern Effekte erwartet werden. Daher müssen Analysen die Daten über mehrere Zeitfenster hinweg explorieren. Darüber hinaus sind statistische Analysen, die alle Elektroden berücksichtigen, wünschenswert, aber nicht trivial. Zur Lösung dieser Probleme präsentieren wir hier das Programm Ragu (Randomization Graphical User interface), das spezifisch für die statistische Auswertung von Mehrkanal EEG-Experimenten eingesetzt werden kann. Ragu soll Wissenschaftlern die Möglichkeit geben, die Signifikanzen von EKP-Effekten global zu untersuchen, ohne die Notwendigkeit von A-Priori-Annahmen. Das Programm basiert auf der Messung von Feldstärke-Differenzen unter Berücksichtigung aller Elektroden. Im ersten Teil dieses Workshops werden wir die Notwendigkeit von topografischen ERP-Analysen angesichts des Volumenleitungsproblems herausarbeiten und Vergleiche zu Einzelelektroden-Ansätzen anstellen. Wir werden an Hand unserer frei erhältlichen in-house Software Ragu das Prinzip von Randomisierungsstatistiken erklären und deren unterschiedliche Anwendungsmöglichkeiten für ERP-Analysen. In einem zweiten Teil haben die Teilnehmenden die Gelegenheit, Ragu an einem Beispielsatz auszuprobieren und Möglichkeiten der Anwendung von Ragu in ihrer eigenen Forschungs zu besprechen.
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Therapeutic resistance remains the principal problem in acute myeloid leukemia (AML). We used area under receiver-operating characteristic curves (AUCs) to quantify our ability to predict therapeutic resistance in individual patients, where AUC=1.0 denotes perfect prediction and AUC=0.5 denotes a coin flip, using data from 4601 patients with newly diagnosed AML given induction therapy with 3+7 or more intense standard regimens in UK Medical Research Council/National Cancer Research Institute, Dutch–Belgian Cooperative Trial Group for Hematology/Oncology/Swiss Group for Clinical Cancer Research, US cooperative group SWOG and MD Anderson Cancer Center studies. Age, performance status, white blood cell count, secondary disease, cytogenetic risk and FLT3-ITD/NPM1 mutation status were each independently associated with failure to achieve complete remission despite no early death (‘primary refractoriness’). However, the AUC of a bootstrap-corrected multivariable model predicting this outcome was only 0.78, indicating only fair predictive ability. Removal of FLT3-ITD and NPM1 information only slightly decreased the AUC (0.76). Prediction of resistance, defined as primary refractoriness or short relapse-free survival, was even more difficult. Our limited ability to forecast resistance based on routinely available pretreatment covariates provides a rationale for continued randomization between standard and new therapies and supports further examination of genetic and posttreatment data to optimize resistance prediction in AML.
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Paper 1: Pilot study of Swiss firms Abstract Using a fixed effects approach, we investigate whether the presence of specific individuals on Swiss firms’ boards affects firm performance and the policy choices they make. We find evidence for a substantial impact of these directors’ presence on their firms. Moreover, the director effects are correlated across policies and performance measures but uncorrelated to the directors’ background. We find these results interesting but conclude that they should to be substantiated on a dataset that is larger and better understood by researchers. Also, further tests are required to rule out methodological concerns. Paper 2: Evidence from the S&P 1,500 Abstract We ask whether directors on corporate boards contribute to firm performance as individuals. From the universe of the S&P 1,500 firms since 1996 we track 2,062 directors who serve on multiple boards over extended periods of time. Our initial findings suggest that the presence of these directors is associated with substantial performance shifts (director fixed effects). Closer examination shows that these effects are statistical artifacts and we conclude that directors are largely fungible. Moreover, we contribute to the discussion of the fixed effects method. In particular, we highlight that the selection of the randomization method is pivotal when generating placebo benchmarks. Paper 3: Robustness, statistical power, and important directors Abstract This article provides a better understanding of Senn’s (2014) findings: The outcome that individual directors are unrelated to firm performance proves robust against different estimation models and testing strategies. By looking at CEOs, the statistical power of the placebo benchmarking test is evaluated. We find that only the stronger tests are able to detect CEO fixed effects. However, these tests are not suitable to analyze directors. The suitable tests would detect director effects if the inter quartile range of the true effects amounted to 3 percentage points ROA. As Senn (2014) finds no such effects for outside directors in general, we focus on groups of particularly important directors (e.g., COBs, non-busy directors, successful directors). Overall, our evidence suggests that the members of these groups are not individually associated with firm performance either. Thus, we confirm that individual directors are largely fungible. If the individual has an effect on performance, it is of small magnitude.
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BACKGROUND AND PURPOSE Treatment with statins reduces the rate of cardiovascular events in high-risk patients, but residual risk persists. At least part of that risk may be attributable to atherogenic dyslipidemia characterized by low high-density lipoprotein cholesterol (≤40 mg/dL) and high triglycerides (triglycerides≥150 mg/dL). METHODS We studied subjects with stroke or transient ischemic attack in the Prevention of Cerebrovascular and Cardiovascular Events of Ischemic Origin With Terutroban in Patients With a History of Ischemic Stroke or Transient Ischemic Attack (PERFORM; n=19,100) and Stroke Prevention by Aggressive Reduction in Cholesterol Levels (SPARCL; n=4731) trials who were treated with a statin and who had high-density lipoprotein cholesterol and triglycerides measurements 3 months after randomization (n=10,498 and 2900, respectively). The primary outcome measure for this exploratory analysis was the occurrence of major cardiovascular events (nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death). We also performed a time-varying analysis to account for all available high-density lipoprotein cholesterol and triglyceride measurements. RESULTS A total of 10% of subjects in PERFORM and 9% in SPARCL had atherogenic dyslipidemia after ≥3 months on start statin therapy. After a follow-up of 2.3 years (PERFORM) and 4.9 years (SPARCL), a major cardiovascular event occurred in 1123 and 485 patients in the 2 trials, respectively. The risk of major cardiovascular events was higher in subjects with versus those without atherogenic dyslipidemia in both PERFORM (hazard ratio, 1.36; 95% confidence interval, 1.14-1.63) and SPARCL (hazard ratio, 1.40; 95% confidence interval, 1.06-1.85). The association was attenuated after multivariable adjustment (hazard ratio, 1.23; 95% confidence interval, 1.03-1.48 in PERFORM and hazard ratio, 1.24; 95% confidence interval, 0.93-1.65 in SPARCL). Time-varying analysis confirmed these findings. CONCLUSIONS The presence of atherogenic dyslipidemia was associated with higher residual cardiovascular risk in PERFORM and SPARCL subjects with stroke or transient ischemic attack receiving statin therapy. Specific therapeutic interventions should now be trialed to address this residual risk.
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IMPORTANCE High-dose immunosuppressive therapy and autologous hematopoietic stem cell transplantation (HSCT) have shown efficacy in systemic sclerosis in phase 1 and small phase 2 trials. OBJECTIVE To compare efficacy and safety of HSCT vs 12 successive monthly intravenous pulses of cyclophosphamide. DESIGN, SETTING, AND PARTICIPANTS The Autologous Stem Cell Transplantation International Scleroderma (ASTIS) trial, a phase 3, multicenter, randomized (1:1), open-label, parallel-group, clinical trial conducted in 10 countries at 29 centers with access to a European Group for Blood and Marrow Transplantation-registered transplant facility. From March 2001 to October 2009, 156 patients with early diffuse cutaneous systemic sclerosis were recruited and followed up until October 31, 2013. INTERVENTIONS HSCT vs intravenous pulse cyclophosphamide. MAIN OUTCOMES AND MEASURES The primary end point was event-free survival, defined as time from randomization until the occurrence of death or persistent major organ failure. RESULTS A total of 156 patients were randomly assigned to receive HSCT (n = 79) or cyclophosphamide (n = 77). During a median follow-up of 5.8 years, 53 events occurred: 22 in the HSCT group (19 deaths and 3 irreversible organ failures) and 31 in the control group (23 deaths and 8 irreversible organ failures). During the first year, there were more events in the HSCT group (13 events [16.5%], including 8 treatment-related deaths) than in the control group (8 events [10.4%], with no treatment-related deaths). At 2 years, 14 events (17.7%) had occurred cumulatively in the HSCT group vs 14 events (18.2%) in the control group; at 4 years, 15 events (19%) had occurred cumulatively in the HSCT group vs 20 events (26%) in the control group. Time-varying hazard ratios (modeled with treatment × time interaction) for event-free survival were 0.35 (95% CI, 0.16-0.74) at 2 years and 0.34 (95% CI, 0.16-0.74) at 4 years. CONCLUSIONS AND RELEVANCE Among patients with early diffuse cutaneous systemic sclerosis, HSCT was associated with increased treatment-related mortality in the first year after treatment. However, HCST conferred a significant long-term event-free survival benefit. TRIAL REGISTRATION isrctn.org Identifier: ISRCTN54371254.
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BACKGROUND: Enhancing physical activity in overweight and obese individuals is an important means to promote health in this target population. The Health Action Process Approach (HAPA), which was the theoretical framework of this study, focuses on individual self-regulation variables for successful health behavior change. One key self-regulation variable of this model is action control with its three subfacets awareness of intentions, self-monitoring and regulatory effort. The social context of individuals, however, is usually neglected in common health behavior change theories. In order to integrate social influences into the HAPA, this randomized controlled trial investigated the effectiveness of a dyadic conceptualization of action control for promoting physical activity. METHODS/DESIGN: This protocol describes the design of a single-blind randomized controlled trial, which comprises four experimental groups: a dyadic action control group, an individual action control group and two control groups. Participants of this study are overweight or obese, heterosexual adult couples who intend to increase their physical activity. Blocking as means of a gender-balanced randomization is used to allocate couples to conditions and partners to either being the target person of the intervention or to the partner condition. The ecological momentary intervention takes place in the first 14 days after baseline assessment and is followed by another 14 days diary phase without intervention. Follow-ups are one month and six months later. Subsequent to the six-months follow-up another 14 days diary phase takes place.The main outcome measures are self-reported and accelerometer-assessed physical activity. Secondary outcome measures are Body Mass Index (BMI), aerobic fitness and habitual physical activity. DISCUSSION: This is the first study examining a dyadic action control intervention in comparison to an individual action control condition and two control groups applying a single-blind randomized control trial. Challenges with running couples studies as well as advantages and disadvantages of certain design-related decisions are discussed. This RCT was funded by the Swiss National Science Foundation (PP00P1_133632/1) and was registered on 27/04/2012 at http://www.isrctn.com/ISRCTN15705531.
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Background Major depressive disorder (MDD) places a significant disease burden on individuals as well as on societies. Several web-based interventions for MDD have shown to be effective in reducing depressive symptoms. However, it is not known whether web-based interventions, when used as adjunctive treatment tools to regular psychotherapy, have an additional effect compared to regular psychotherapy for depression. Methods/design This study is a currently recruiting pragmatic randomized controlled trial (RCT) that compares regular psychotherapy plus a web-based depression program (¿deprexis¿) with a control condition exclusively receiving regular psychotherapy. Adults with a depressive disorder (N?=?800) will be recruited in routine secondary care from therapists over the course of their initial sessions and will then be randomized within therapists to one of the two conditions. The primary outcome is depressive symptoms measured with the Beck Depression Inventory (BDI-II) at three months post randomization. Secondary outcomes include changes on various indicators such as anxiety, somatic symptoms and quality of life. All outcomes are again assessed at the secondary endpoint six months post randomization. In addition, the working alliance and feasibility/acceptability of the treatment condition will be explored. Discussion This is the first randomized controlled trial to examine the feasibility/acceptability and the effectiveness of a combination of traditional face-to-face psychotherapy and web-based depression program compared to regular psychotherapeutic treatment in depressed outpatients in routine care.
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Until recently, the repair of asymptomatic groin hernia has been advocated as a prophylaxis for incarceration. However, incarcerations of inguinal hernias are rare events and can be treated adequately if the patient presents himself early after onset of symptoms. Randomized controlled trials showed, that watchful waiting is not associated with increased incarcerations and can be offered as a save alternative. However, within seven years after randomization 50 % to 70 % of the patients in the watchful waiting groups required surgery, mainly because of new onset or increasing symptoms.
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BACKGROUND: Enhancing physical activity in overweight and obese individuals is an important means to promote health in this target population. The Health Action Process Approach (HAPA), which was the theoretical framework of this study, focuses on individual self-regulation variables for successful health behavior change. One key self-regulation variable of this model is action control with its three subfacets awareness of intentions, self-monitoring and regulatory effort. The social context of individuals, however, is usually neglected in common health behavior change theories. In order to integrate social influences into the HAPA, this randomized controlled trial investigated the effectiveness of a dyadic conceptualization of action control for promoting physical activity. METHODS/DESIGN: This protocol describes the design of a single-blind randomized controlled trial, which comprises four experimental groups: a dyadic action control group, an individual action control group and two control groups. Participants of this study are overweight or obese, heterosexual adult couples who intend to increase their physical activity. Blocking as means of a gender-balanced randomization is used to allocate couples to conditions and partners to either being the target person of the intervention or to the partner condition. The ecological momentary intervention takes place in the first 14 days after baseline assessment and is followed by another 14 days diary phase without intervention. Follow-ups are one month and six months later. Subsequent to the six-months follow-up another 14 days diary phase takes place.The main outcome measures are self-reported and accelerometer-assessed physical activity. Secondary outcome measures are Body Mass Index (BMI), aerobic fitness and habitual physical activity. DISCUSSION: This is the first study examining a dyadic action control intervention in comparison to an individual action control condition and two control groups applying a single-blind randomized control trial. Challenges with running couples studies as well as advantages and disadvantages of certain design-related decisions are discussed. This RCT was funded by the Swiss National Science Foundation (PP00P1_133632/1) and was registered on 27/04/2012 at http://www.isrctn.com/ISRCTN15705531.
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In chronic lymphocytic leukemia (CLL) medical progress is driven by clinical studies with relapse-free survival (RFS) as the primary endpoint. The randomized EBMT-Intergroup trial compared high-dose therapy and autologous stem cell transplantation (ASCT) to observation and demonstrated a substantial improvement of RFS without showing improved overall survival for the transplant arm. Here we report quality of life (QoL) information of the first 3 years following randomization from that study. The main objective was to assess the impact of treatment on QoL over time. Two secondary analyses were performed to further investigate the impact of ASCT and relapse on QoL. In the primary analysis, we demonstrate an adverse impact of ASCT on QoL which was largest at 4 months and continued throughout the first year after randomization. Further, we demonstrated a sustained adverse impact of relapse on QoL which worsened over time. Despite better disease control by ASCT the side effects thus turned the net effect towards inferior QoL in the first year and comparable QoL in the following 2 years after randomization. This study emphasizes the importance of information concerning QoL impacts when patients are counseled about treatments aimed at improving RFS in the absence of a survival benefit.
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AIMS: To determine the efficacy of motivational enhancement therapy (MET) on alcohol use in patients with the hepatitis C virus (HCV) and an alcohol use disorder (AUD). DESIGN: Randomized, single-blind, controlled trial comparing MET to a control education condition with 6-month follow-up. SETTING: Patients were recruited from hepatitis clinics at the Minneapolis, Minnesota and Portland, Oregon Veterans Affairs Health Care Systems, USA. PARTICIPANTS AND INTERVENTION: Patients with HCV, an AUD and continued alcohol use (n = 139) were randomized to receive either MET (n = 70) or a control education condition (n = 69) over 3 months. MEASUREMENTS: Data were self-reported percentage of days abstinent from alcohol and number of standard alcohol drinks per week 6 months after randomization. FINDINGS: At baseline, subjects in MET had 34.98% days abstinent, which increased to 73.15% at 6 months compared to 34.63 and 59.49% for the control condition. Multi-level models examined changes in alcohol consumption between MET and control groups. Results showed a significant increase in percentage of days abstinent overall (F(1120.4) = 28.04, P < 0.001) and a significant group × time effect (F(1119.9) = 5.23, P = 0.024) with the MET group showing a greater increase in percentage of days abstinent at 6 months compared with the education control condition. There were no significant differences between groups for drinks per week. The effect size of the MET intervention was moderate (0.45) for percentage of days abstinent. CONCLUSION: Motivational enhancement therapy (MET) appears to increase the percentage of days abstinent in patients with chronic hepatitis C, alcohol use disorders and ongoing alcohol use. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.