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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
01 Nov 1997-Pain
TL;DR: A meta‐analysis of the controlled clinical trial data for peripheral neuropathic pain (PNP) and complex regional pain syndromes (CRPS) indicated that mexiletine and intravenous morphine were probably effective analgesics for PNP, while non‐steroidals were probably ineffective.
Abstract: The purpose of this review was to identify and analyze the controlled clinical trial data for peripheral neuropathic pain (PNP) and complex regional pain syndromes (CRPS). A total of 72 articles were found, which included 92 controlled drug trials using 48 different treatments. The methods of these studies were critically reviewed and the results summarized and compared. The PNP trial literature gave consistent support (two or more trials) for the analgesic effectiveness of tricyclic antidepressants, intravenous and topical lidocaine, intravenous ketamine, carbamazepine and topical aspirin. There was limited support (one trial) for the analgesic effectiveness of oral, topical and epidural clonidine and for subcutaneous ketamine. The trial data were contradictory for mexiletine, phenytoin, topical capsaicin, oral non-steroidal anti-inflammatory medication, and intravenous morphine. Analysis of the trial methods indicated that mexiletine and intravenous morphine were probably effective analgesics for PNP, while non-steroidals were probably ineffective. Codeine, magnesium chloride, propranolol, lorazepam, and intravenous phentolamine all failed to provide analgesia in single trials. There were no long-term data supporting the analgesic effectiveness of any drug and the etiology of the neuropathy did not predict treatment outcome. Review of the controlled trial literature for CRPS identified several potential problems with current clinical practices. The trial data only gave consistent support for analgesia with corticosteroids, which had long-term effectiveness. There was limited support for the analgesic effectiveness of topical dimethylsulfoxyde (DMSO), epidural clonidine and intravenous regional blocks (IVRBs) with bretylium and ketanserin. The trial data were contradictory for intranasal calcitonin and intravenous phentolamine and analysis of the trial methods indicated that both treatments were probably ineffective for most patients. There were consistent trial data indicating that guanethidine and reserpine IVRBs were ineffective, and limited trial data indicating that droperidol and atropine IVRBs were ineffective. No placebo controlled data were available to evaluated sympathetic ganglion blocks (SGBs) with local anesthetics, surgical sympathectomy, or physical therapy. Only the capsaicin trials presented data which allowed for meta-analysis. This meta-analysis demonstrated a significant capsaicin effect with a pooled odds ratio of 2.35 (95% confidence intervals 1.48, 3.22). The methods scores were higher (P<0.01) for the PNP trials (66.2±1.5, n=66) than the CRPS trials (57.6±2.9, n=26). The CRPS trials tended to use less subjects and were less likely to use placebo controls, double-blinding, or perform statistical tests for differences in outcome measures between groups. There was almost no overlap in the controlled trial literature between treatments for PNP and CRPS, and treatments used in both conditions (intravenous phentolamine and epidural clonidine) had similar results.

685 citations

Journal ArticleDOI
TL;DR: These two transdiagnostic treatments appear to be suitable for the majority of outpatients with an eating disorder and the simpler treatment may best be viewed as the default version, with the more complex treatment reserved for patients with marked additional psychopathology of the type targeted by the treatment.
Abstract: Objective: The aim of this study was to compare two cognitive-behavioral treatments for outpatients with eating disorders, one focusing solely on eating disorder features and the other a more complex treatment that also addresses mood intolerance, clinical perfectionism, low self-esteem, or interpersonal difficulties. Method: A total of 154 patients who had a DSM-IV eating disorder but were not markedly underweight (body mass index over 17.5), were enrolled in a two-site randomized controlled trial involving 20 weeks of treatment and a 60-week closed period of follow-up. The control condition was an 8-week waiting list period preceding treatment. Outcomes were measured by independent assessors who were blind to treatment condition. Results: Patients in the waiting list control condition exhibited little change in symptom severity, whereas those in the two treatment conditions exhibited substantial and equivalent change, which was well maintained during follow-up. At the 60-week follow-up assessment, 51.3% of the sample had a level of eating disorder features less than one standard deviation above the community mean. Treatment outcome did not depend on eating disorder diagnosis. Patients with marked mood intolerance, clinical perfectionism, low self-esteem, or interpersonal difficulties appeared to respond better to the more complex treatment, with the reverse pattern evident among the remaining patients. Conclusions: These two transdiagnostic treatments appear to be suitable for the majority of outpatients with an eating disorder. The simpler treatment may best be viewed as the default version, with the more complex treatment reserved for patients with marked additional psychopathology of the type targeted by the treatment.

684 citations

Journal ArticleDOI
23 Jul 1997-JAMA
TL;DR: An overview of all published randomized trials of statin drugs demonstrates large reductions in cholesterol and clear evidence of benefit on stroke and total mortality, but there was no significant evidence for any increases in either non-CVD deaths or cancer incidence.
Abstract: Objective. —To examine whether cholesterol lowering with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statin drugs) reduces the risks of stroke and total mortality. Data Sources. —We conducted a computerized literature search from 1985 through 1995 to identify all published trials testing statin drugs. The Cholesterol and Recurrent Events (CARE) data were added after the report was published in October 1996. Our search was limited to English-language articles and included published overviews containing relevant individual trials. Trial Selection. —Criteria for inclusion of randomized trials in the overview were (1) statin drugs alone used to reduce lipid levels rather than multifactorial interventions including another type of cholesterol-lowering drug and (2) inclusion of data on deaths and/or strokes. Data Extraction. —Data were extracted by 2 researchers, and only minor discrepancies, which were easily resolved by discussion, occurred. Principal investigators of the trials and their funding agencies were also contacted to secure any relevant data not included in the published reports. Data Ssynthesis. —A total of 16 individual trials including approximately 29 000 subjects treated and followed up an average of 3.3 years were included in the overview. The average reductions in total and low-density lipoprotein cholesterol achieved were large—22% and 30%, respectively. A total of 454 strokes (fatal plus nonfatal) and 1175 deaths occurred. Those assigned to statin drugs experienced significant reductions in risks of stroke of 29% (95% confidence interval [CI], 14%-41%) as well as total mortality of 22% (95% CI, 12%-31%), which was attributable to a significant reduction in cardiovascular disease (CVD) deaths of 28% (95% CI, 16%-37%). There was no evidence of any increased risk in non-CVD mortality (relative risk [RR], 0.93; 95% CI, 0.75-1.14). There was also no significant increase in risk of cancer (RR, 1.03; 95% CI, 0.90-1.17). Conclusion. —This overview of all published randomized trials of statin drugs demonstrates large reductions in cholesterol and clear evidence of benefit on stroke and total mortality. There was, as expected, a large and significant decrease in CVD mortality, but there was no significant evidence for any increases in either non-CVD deaths or cancer incidence.

683 citations

Journal ArticleDOI
TL;DR: It is indicated that ACT is more effective than treatment as usual or placebo and that ACT may be as effective in treating anxiety disorders, depression, addiction, and somatic health problems as established psychological interventions.
Abstract: Background: The current study presents the results of a meta-analysis of 39 randomized controlled trials on the efficacy of acceptance and commitment therapy (ACT), including 1,821 patients with mental disorders or somatic health problems. Methods: We searched PsycINFO, MEDLINE and the Cochrane Central Register of Controlled Trials. Information provided by the ACBS (Association of Contextual Behavioral Science) community was also included. Statistical calculations were conducted using Comprehensive Meta-Analysis software. Study quality was rated using a methodology rating form. Results: ACT outperformed control conditions (Hedges' g = 0.57) at posttreatment and follow-up assessments in completer and intent-to-treat analyses for primary outcomes. ACT was superior to waitlist (Hedges' g = 0.82), to psychological placebo (Hedges' g = 0.51) and to treatment as usual (TAU) (we defined TAU as the standard treatment as usual; Hedges' g = 0.64). ACT was also superior on secondary outcomes (Hedges' g = 0.30), life satisfaction/quality measures (Hedges' g = 0.37) and process measures (Hedges' g = 0. 56) compared to control conditions. The comparison between ACT and established treatments (cognitive behavioral therapy) did not reveal any significant differences between these treatments (p = 0.140). Conclusions: Our findings indicate that ACT is more effective than treatment as usual or placebo and that ACT may be as effective in treating anxiety disorders, depression, addiction, and somatic health problems as established psychological interventions. More research that focuses on quality of life and processes of change is needed to understand the added value of ACT and its transdiagnostic nature.

682 citations

Journal ArticleDOI
TL;DR: The findings suggest that the discrepancies between the Women's Health Initiative and Nurses’ Health Study ITT estimates could be largely explained by differences in the distribution of time since menopause and length of follow-up.
Abstract: Causal inferences are drawn from both randomized experiments and observational studies. When estimates from both types of studies are available, it is reassuring to find that they are often similar.1–3 On the other hand, when randomized and observational estimates disagree, it is tempting to attribute the differences to the lack of random treatment assignment in observational studies. This lack of randomization makes observational effect estimates vulnerable to confounding bias due to the different prognosis of individuals between treatment groups. The potential for confounding may diminish the enthusiasm for other desirable features of observational studies compared with randomized experiments – greater timeliness, less restrictive eligibility criteria, longer follow-up, and lower cost. However, even though randomization is the defining difference between randomized experiments and observational studies, further differences in both design and analysis are commonplace. As a consequence, observational-randomized discrepancies cannot be automatically attributed to randomization itself. In this paper we assess the extent to which differences other than randomization contribute to discrepant observational versus randomized effect estimates in the well-known example of postmenopausal estrogen plus progestin therapy and the risk of coronary heart disease (CHD). Specifically, we explore discrepancies attributable to different distributions of time since menopause, length of follow-up, and analytic approach. The published findings on this topic can be briefly summarized as follows. Large observational studies suggested a reduced risk of CHD among postmenopausal hormone users. Two of the largest observational studies were based on the Nurses’ Health Study (NHS)4, 5 in the United States and on the General Practice Research Database6 in the United Kingdom. More recently, the Women’s Health Initiative (WHI) randomized trial7 found a greater incidence of coronary heart disease among postmenopausal women in the estrogen plus progestin arm than in the placebo arm (68% greater in the first two years after initiation, 24% greater after an average of 5.6 years).8, 9 The present paper does not address the complex clinical and public health issues related to hormone therapy, including risk-benefit considerations. Rather, we focus on methodologic issues in the analysis of observational cohort studies. Specifically, we reanalyze the NHS observational data to yield effect estimates of hormone therapy that are directly comparable with those of the randomized WHI trial except for the fact that hormone therapy was not randomly assigned in the NHS. We do this by mimicking the design of the randomized trial as closely as possible in the NHS. As explained below, our approach requires conceptualizing the observational NHS cohort as if it were a sequence of nonrandomized “trials.” Because the randomized trial data were analyzed under the intention-to-treat (ITT) principle, we analyze our NHS “trials” using an observational analog of ITT (see below). A recent re-analysis of the General Practice Research Database using this strategy could not adjust for lifestyle factors and it yielded wide confidence intervals.10 Further, the estrogen used by women in that study was not the conjugated equine estrogen used by the women in the NHS and WHI studies. Our analysis of the NHS data incorporates lifestyle factors and includes women using the same type of estrogen as in the WHI randomized trial.

682 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