Controlled clinical trials
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Control Clin Trials · Feb 1996
Meta AnalysisAssessing the quality of reports of randomized clinical trials: is blinding necessary?
It has been suggested that the quality of clinical trials should be assessed by blinded raters to limit the risk of introducing bias into meta-analyses and systematic reviews, and into the peer-review process. There is very little evidence in the literature to substantiate this. This study describes the development of an instrument to assess the quality of reports of randomized clinical trials (RCTs) in pain research and its use to determine the effect of rater blinding on the assessments of quality. ⋯ These items were scored consistently by all the raters regardless of background and could discriminate between reports from the different samples. Blind assessments produced significantly lower and more consistent scores than open assessments. The implications of this finding for systematic reviews, meta-analytic research and the peer-review process are discussed.
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Control Clin Trials · Dec 2004
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialSymptom recording in a randomised clinical trial: paper diaries vs. electronic or telephone data capture.
Patients may be asked to register a symptom daily in clinical trials. A problem associated with this kind of registration is that patients do not always fill in the diary at the appropriate time. As there is evidence showing that memory is unreliable, this undermines the entire purpose of collecting daily data on paper diaries. We aimed to compare accuracy, autocorrelations of consecutive entries, and responsiveness in paper diaries (P-Diaries) with electronic diaries (E-Diaries) and telephone diaries (T-Diaries). ⋯ The results are consistent with the suggestion that data in the P-Diaries are not filled in at the appropriate time. Use of E-Diaries or T-Diaries improves quality and is recommended in future clinical trials.
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Response-adaptive designs in clinical trials are schemes for patient assignment to treatment, the goal of which is to place more patients on the better treatment based on patient responses already accrued in the trial. While ethically attractive at first glance, these designs have had very little use in practice; yet the statistical literature is rich on this subject. ⋯ We also discuss reasons for the lack of use of these models, and areas of current and future research to address the weaknesses of these methods. We conclude that these designs may be applicable in some situations and describe conditions under which such a trial may be feasible.
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Control Clin Trials · Feb 1995
Randomized Controlled Trial Multicenter Study Clinical TrialThe SvO2 study: general design and results of the feasibility phase of a multicenter, randomized trial of three different hemodynamic approaches and two monitoring techniques in the treatment of critically ill patients. The SvO2 Collaborative Group.
Although the attainment of normal hemodynamic values has always been assumed to be the therapeutic target for critically ill patients, recent studies reported increased values in oxygen transport variables in survivors of high-risk surgery. It has been supposed that the higher values observed in survivors might indicate a physiological compensation for the increased metabolic requirements due to disease. ⋯ Two different monitoring systems are used to maintain the target: conventional Swan-Ganz catheter with scheduled samples of mixed venous O2 saturation, and optical catheter with continuous SvO2 evaluation. The aim of the study is to answer three questions regarding the hypothesis reported above: (1) Are results in postoperative patients applicable to other pathological groups? (2) Does continuous monitoring of SvO2 provide advantages over conventional hemodynamic monitoring? (3) Is a normal SvO2 rather than a supranormal CI a good and predictable therapeutic goal? We report herein the protocol of the study and the results of the pilot phase, which was conducted in 98 critically ill patients enrolled by 56 participating centers to evaluate the safety and feasibility of the proposed trial.
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Control Clin Trials · Aug 2001
Randomized Controlled Trial Clinical TrialThe inhaled Steroid Treatment as Regular Therapy in early asthma (START) study: rationale and design.
Although the beneficial effects of treatment with inhaled steroids in asthma are widely accepted, the role of early intervention in patients with mild asthma remains unsettled. Conventional efficacy trials are often of short duration and involve highly selected patient populations that exclude many patients typical of those encountered in routine clinical practice. Hence, a large "real-world" effectiveness study is needed to evaluate the benefits of early intervention with inhaled steroids in patients with mild, persistent asthma. ⋯ Lung function will be measured by spirometry using standardized techniques at 3-month intervals throughout the study, and bronchodilator reversibility will be measured annually. The primary outcome measures are the time to the first severe asthma-related event during the first 3 years of the study and the change in postbronchodilator forced expiratory volume in 1 second (FEV(1)) from baseline during the entire 5-year study period. These measures have been chosen to reflect the progression of mild asthma toward more severe asthma and the extent of irreversible airflow limitation, which should reflect the degree of airway remodeling.