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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.


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Journal ArticleDOI
21 May 2003-JAMA
TL;DR: Low-dose diuretics are the most effective first-line treatment for preventing the occurrence of cardiovascular disease morbidity and mortality and future trials should use low-doseDiuretics as the standard for clinically useful comparisons.
Abstract: ContextEstablishing relative benefit or harm from specific antihypertensive agents is limited by the complex array of studies that compare treatments. Network meta-analysis combines direct and indirect evidence to better define risk or benefit.ObjectiveTo summarize the available clinical trial evidence concerning the safety and efficacy of various antihypertensive therapies used as first-line agents and evaluated in terms of major cardiovascular disease end points and all-cause mortality.Data Sources and Study SelectionWe used previous meta-analyses, MEDLINE searches, and journal reviews from January 1995 through December 2002. We identified long-term randomized controlled trials that assessed major cardiovascular disease end points as an outcome. Eligible studies included both those with placebo-treated or untreated controls and those with actively treated controls.Data ExtractionNetwork meta-analysis was used to combine direct within-trial between-drug comparisons with indirect evidence from the other trials. The indirect comparisons, which preserve the within-trial randomized findings, were constructed from trials that had one treatment in common.Data SynthesisData were combined from 42 clinical trials that included 192 478 patients randomized to 7 major treatment strategies, including placebo. For all outcomes, low-dose diuretics were superior to placebo: coronary heart disease (CHD; RR, 0.79; 95% confidence interval [CI], 0.69-0.92); congestive heart failure (CHF; RR, 0.51; 95% CI, 0.42-0.62); stroke (RR, 0.71; 0.63-0.81); cardiovascular disease events (RR, 0.76; 95% CI, 0.69-0.83); cardiovascular disease mortality (RR, 0.81; 95% CI, 0.73-0.92); and total mortality (RR, 0.90; 95% CI, 0.84-0.96). None of the first-line treatment strategies–β-blockers, angiotensin-converting enzyme (ACE) inhibitors, calcium channel blockers (CCBs), α-blockers, and angiotensin receptor blockers–was significantly better than low-dose diuretics for any outcome. Compared with CCBs, low-dose diuretics were associated with reduced risks of cardiovascular disease events (RR, 0.94; 95% CI, 0.89-1.00) and CHF (RR, 0.74; 95% CI, 0.67-0.81). Compared with ACE inhibitors, low-dose diuretics were associated with reduced risks of CHF (RR, 0.88; 95% CI, 0.80-0.96), cardiovascular disease events (RR, 0.94; 95% CI, 0.89-1.00), and stroke (RR, 0.86; 0.77-0.97). Compared with β-blockers, low-dose diuretics were associated with a reduced risk of cardiovascular disease events (RR, 0.89; 95% CI, 0.80-0.98). Compared with α-blockers, low-dose diuretics were associated with reduced risks of CHF (RR, 0.51; 95% CI, 0.43-0.60) and cardiovascular disease events (RR, 0.84; 95% CI, 0.75-0.93). Blood pressure changes were similar between comparison treatments.ConclusionsLow-dose diuretics are the most effective first-line treatment for preventing the occurrence of cardiovascular disease morbidity and mortality. Clinical practice and treatment guidelines should reflect this evidence, and future trials should use low-dose diuretics as the standard for clinically useful comparisons.

1,074 citations

Journal ArticleDOI
08 Jun 2011-JAMA
TL;DR: Among women in the general US population, simultaneous screening with CA-125 and transvaginal ultrasound compared with usual care did not reduce ovarian cancer mortality.
Abstract: Context Screening for ovarian cancer with cancer antigen 125 (CA-125) and transvaginal ultrasound has an unknown effect on mortality. Objective To evaluate the effect of screening for ovarian cancer on mortality in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. Design, Setting, and Participants Randomized controlled trial of 78 216 women aged 55 to 74 years assigned to undergo either annual screening (n = 39 105) or usual care (n = 39 111) at 10 screening centers across the United States between November 1993 and July 2001. Intervention The intervention group was offered annual screening with CA-125 for 6 years and transvaginal ultrasound for 4 years. Participants and their health care practitioners received the screening test results and managed evaluation of abnormal results. The usual care group was not offered annual screening with CA-125 for 6 years or transvaginal ultrasound but received their usual medical care. Participants were followed up for a maximum of 13 years (median [range], 12.4 years [10.9-13.0 years]) for cancer diagnoses and death until February 28, 2010. Main Outcome Measures Mortality from ovarian cancer, including primary peritoneal and fallopian tube cancers. Secondary outcomes included ovarian cancer incidence and complications associated with screening examinations and diagnostic procedures. Results Ovarian cancer was diagnosed in 212 women (5.7 per 10 000 person-years) in the intervention group and 176 (4.7 per 10 000 person-years) in the usual care group (rate ratio [RR], 1.21; 95% confidence interval [CI], 0.99-1.48). There were 118 deaths caused by ovarian cancer (3.1 per 10 000 person-years) in the intervention group and 100 deaths (2.6 per 10 000 person-years) in the usual care group (mortality RR, 1.18; 95% CI, 0.82-1.71). Of 3285 women with false-positive results, 1080 underwent surgical follow-up; of whom, 163 women experienced at least 1 serious complication (15%). There were 2924 deaths due to other causes (excluding ovarian, colorectal, and lung cancer) (76.6 per 10 000 person-years) in the intervention group and 2914 deaths (76.2 per 10 000 person-years) in the usual care group (RR, 1.01; 95% CI, 0.96-1.06). Conclusions Among women in the general US population, simultaneous screening with CA-125 and transvaginal ultrasound compared with usual care did not reduce ovarian cancer mortality. Diagnostic evaluation following a false-positive screening test result was associated with complications. Trial Registration clinicaltrials.gov Identifier: NCT00002540

1,073 citations

Journal ArticleDOI
TL;DR: Type or intensity of 14 months of treatment for ADHD in childhood does not predict functioning 6 to 8 years later, and early ADHD symptom trajectory regardless of treatment type is prognostic, implying that children with behavioral and sociodemographic advantage, with the best response to any treatment, will have the best long-term prognosis.
Abstract: Objectives To determine any long-term effects, 6 and 8 years after childhood enrollment, of the randomly assigned 14-month treatments in the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA; N = 436); to test whether attention-deficit/hyperactivity disorder (ADHD) symptom trajectory through 3 years predicts outcome in subsequent years; and to examine functioning level of the MTA adolescents relative to their non-ADHD peers (local normative comparison group; N = 261). Method Mixed-effects regression models with planned contrasts at 6 and 8 years tested a wide range of symptom and impairment variables assessed by parent, teacher, and youth report. Results In nearly every analysis, the originally randomized treatment groups did not differ significantly on repeated measures or newly analyzed variables (e.g., grades earned in school, arrests, psychiatric hospitalizations, other clinically relevant outcomes). Medication use decreased by 62% after the 14-month controlled trial, but adjusting for this did not change the results. ADHD symptom trajectory in the first 3 years predicted 55% of the outcomes. The MTA participants fared worse than the local normative comparison group on 91% of the variables tested. Conclusions Type or intensity of 14 months of treatment for ADHD in childhood (at age 7.0–9.9 years) does not predict functioning 6 to 8 years later. Rather, early ADHD symptom trajectory regardless of treatment type is prognostic. This finding implies that children with behavioral and sociodemographic advantage, with the best response to any treatment, will have the best long-term prognosis. As a group, however, despite initial symptom improvement during treatment that is largely maintained after treatment, children with combined-type ADHD exhibit significant impairment in adolescence. Innovative treatment approaches targeting specific areas of adolescent impairment are needed.

1,070 citations

Journal ArticleDOI
TL;DR: Two different propensity score methods (matching and inverse probability of treatment weighting) can be used to estimate the measures of effect that are frequently reported in randomized controlled trials with time‐to‐event outcomes: marginal survival curves and marginal hazard ratios.
Abstract: Propensity score methods are increasingly being used to estimate causal treatment effects in observational studies. In medical and epidemiological studies, outcomes are frequently time-to-event in nature. Propensity-score methods are often applied incorrectly when estimating the effect of treatment on time-to-event outcomes. This article describes how two different propensity score methods (matching and inverse probability of treatment weighting) can be used to estimate the measures of effect that are frequently reported in randomized controlled trials: (i) marginal survival curves, which describe survival in the population if all subjects were treated or if all subjects were untreated; and (ii) marginal hazard ratios. The use of these propensity score methods allows one to replicate the measures of effect that are commonly reported in randomized controlled trials with time-to-event outcomes: both absolute and relative reductions in the probability of an event occurring can be determined. We also provide guidance on variable selection for the propensity score model, highlight methods for assessing the balance of baseline covariates between treated and untreated subjects, and describe the implementation of a sensitivity analysis to assess the effect of unmeasured confounding variables on the estimated treatment effect when outcomes are time-to-event in nature. The methods in the paper are illustrated by estimating the effect of discharge statin prescribing on the risk of death in a sample of patients hospitalized with acute myocardial infarction. In this tutorial article, we describe and illustrate all the steps necessary to conduct a comprehensive analysis of the effect of treatment on time-to-event outcomes. © 2013 The authors. Statistics in Medicine published by John Wiley & Sons, Ltd.

1,065 citations

Journal ArticleDOI
TL;DR: In patients with type 2 diabetes and cardiovascular disease, albiglutide was superior to placebo with respect to major adverse cardiovascular events, and evidence-based glucagon-like peptide 1 receptor agonists should be considered as part of a comprehensive strategy to reduce the risk of cardiovascular events.

1,064 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
202317,032
202234,327
202112,220
202010,774
20199,017