Randomized controlled trial

About: Randomized controlled trial is a research topic. Over the lifetime, 119828 publications have been published within this topic receiving 4861808 citations. The topic is also known as: RCT & randomized control trial.

Bias in Treatment Assignment in Controlled Clinical Trials

Abstract: Controlled clinical trials of the treatment of acute myocardial infarction offer a unique opportunity for the study of the potential influence on outcome of bias in treatment assignment. A group of 145 papers was divided into those in which the randomization process was blinded (57 papers), those in which it may have been unblinded (45 papers), and those in which the controls were selected by a nonrandom process (43 papers). At least one prognostic variable was maldistributed (P less than 0.05) in 14.0 per cent of the blinded-randomization studies, in 26.7 per cent of the unblinded-randomization studies, and in 58.1 per cent of the nonrandomized studies. Differences in case-fatality rates between treatment and control groups (P less than 0.05) were found in 8.8 per cent of the blinded-randomization studies, 24.4 per cent of the unblinded-randomization studies, and 58.1 per cent of the nonrandomized studies. These data emphasize the importance of keeping those who recruit patients for clinical trials from suspecting which treatment will be assigned to the patient under consideration.

Comparison of Evidence of Treatment Effects in Randomized and Nonrandomized Studies

Abstract: ContextThere is substantial debate about whether the results of nonrandomized studies are consistent with the results of randomized controlled trials on the same topic.ObjectivesTo compare results of randomized and nonrandomized studies that evaluated medical interventions and to examine characteristics that may explain discrepancies between randomized and nonrandomized studies.Data SourcesMEDLINE (1966–March 2000), the Cochrane Library (Issue 3, 2000), and major journals were searched.Study SelectionForty-five diverse topics were identified for which both randomized trials (n = 240) and nonrandomized studies (n = 168) had been performed and had been considered in meta-analyses of binary outcomes.Data ExtractionData on events per patient in each study arm and design and characteristics of each study considered in each meta-analysis were extracted and synthesized separately for randomized and nonrandomized studies.Data SynthesisVery good correlation was observed between the summary odds ratios of randomized and nonrandomized studies (r = 0.75; P<.001); however, nonrandomized studies tended to show larger treatment effects (28 vs 11; P = .009). Between-study heterogeneity was frequent among randomized trials alone (23%) and very frequent among nonrandomized studies alone (41%). The summary results of the 2 types of designs differed beyond chance in 7 cases (16%). Discrepancies beyond chance were less common when only prospective studies were considered (8%). Occasional differences in sample size and timing of publication were also noted between discrepant randomized and nonrandomized studies. In 28 cases (62%), the natural logarithm of the odds ratio differed by at least 50%, and in 15 cases (33%), the odds ratio varied at least 2-fold between nonrandomized studies and randomized trials.ConclusionsDespite good correlation between randomized trials and nonrandomized studies—in particular, prospective studies—discrepancies beyond chance do occur and differences in estimated magnitude of treatment effect are very common.

A controlled trial of social intervention in the families of schizophrenic patients.

Abstract: A study is reported of a controlled trial of social intervention in the families of schizophrenic patients at high risk of relapse. The patients were selected for being in high contact with high Expressed Emotion relatives. All patients were maintained on neuroleptic drugs. One half of the 24 families were randomly assigned to routine out-patient care, while the other half received a package of social interventions. This comprised a programme of education about schizophrenia, a group for the relatives, and family sessions for relatives and patients. The relapse rate in the control group was 50 per cent compared with nine per cent in the experimental group (P = 0.04). The stated aims of the therapeutic interventions were achieved in 73 per cent of experimental families. In these families, no patient relapsed. The results provide evidence for the causal role of relatives' expressed emotion (EE) in schizophrenic relapse, as well as for the therapeutic effectiveness of social intervention combined with drug treatment.

Low-Dose Methotrexate for the Prevention of Atherosclerotic Events

Abstract: Background Inflammation is causally related to atherothrombosis. Treatment with canakinumab, a monoclonal antibody that inhibits inflammation by neutralizing interleukin-1β, resulted in a lower rate of cardiovascular events than placebo in a previous randomized trial. We sought to determine whether an alternative approach to inflammation inhibition with low-dose methotrexate might provide similar benefit. Methods We conducted a randomized, double-blind trial of low-dose methotrexate (at a target dose of 15 to 20 mg weekly) or matching placebo in 4786 patients with previous myocardial infarction or multivessel coronary disease who additionally had either type 2 diabetes or the metabolic syndrome. All participants received 1 mg of folate daily. The primary end point at the onset of the trial was a composite of nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. Near the conclusion of the trial, but before unblinding, hospitalization for unstable angina that led to urgent revas...