scispace - formally typeset
Search or ask a question
Institution

Cochrane Collaboration

NonprofitOxford, United Kingdom
About: Cochrane Collaboration is a nonprofit organization based out in Oxford, United Kingdom. It is known for research contribution in the topics: Systematic review & Randomized controlled trial. The organization has 1995 authors who have published 3928 publications receiving 382695 citations.


Papers
More filters
Journal ArticleDOI
31 Oct 1998-BMJ
TL;DR: The drug regulatory authorities should stipulate that the results of both explanatory and pragmatic trials are necessary before a compound is given a licence for everyday use, and much scope for well planned, conducted, and reported trials is left.
Abstract: Objective To provide a comprehensive survey of the content and quality of intervention studies relevant to the treatment of schizophrenia. Design Data were extracted from 2000 trials on the Cochrane Schizophrenia Group9s register. Main outcome measures Type and date of publication, country of origin, language, size of study, treatment setting, participant group, interventions, outcomes, and quality of study. Results Hospital based drug trials undertaken in the United States were dominant in the sample (54%). Generally, studies were short (54% Conclusions Half a century of studies of limited quality, duration, and clinical utility leave much scope for well planned, conducted, and reported trials. The drug regulatory authorities should stipulate that the results of both explanatory and pragmatic trials are necessary before a compound is given a licence for everyday use.

343 citations

Journal ArticleDOI
TL;DR: Trialists can increase recruitment to their trials by using the strategies shown to be effective in this review: telephone reminders; use of opt-out, rather than opt-in; procedures for contacting potential trial participants and open designs.
Abstract: BACKGROUND: Recruiting participants to trials can be extremely difficult. Identifying strategies that improve trial recruitment would benefit both trialists and health research. OBJECTIVES: To quantify the effects of strategies to improve recruitment of participants to randomised controlled trials. SEARCH STRATEGY: We searched the Cochrane Methodology Review Group Specialised Register - CMR (The Cochrane Library (online) Issue 1 2008) (searched 20 February 2008); MEDLINE, Ovid (1950 to date of search) (searched 06 May 2008); EMBASE, Ovid (1980 to date of search) (searched 16 May 2008); ERIC, CSA (1966 to date of search) (searched 19 March 2008); Science Citation Index Expanded, ISI Web of Science (1975 to date of search) (searched 19 March 2008); Social Sciences Citation Index, ISI Web of Science (1975 to date of search) (searched 19 March 2008); and National Research Register (online) (Issue 3 2007) (searched 03 September 2007); C2-SPECTR (searched 09 April 2008). We also searched PubMed (25 March 2008) to retrieve "related articles" for 15 studies included in a previous version of this review. SELECTION CRITERIA: Randomised and quasi-randomised controlled trials of methods to increase recruitment to randomised controlled trials. This includes non-healthcare studies and studies recruiting to hypothetical trials. Studies aiming to increase response rates to questionnaires or trial retention, or which evaluated incentives and disincentives for clinicians to recruit patients were excluded. DATA COLLECTION AND ANALYSIS: Data were extracted on the method evaluated; country in which the study was carried out; nature of the population; nature of the study setting; nature of the study to be recruited into; randomisation or quasi-randomisation method; and numbers and proportions in each intervention group. We used risk ratios and their 95% confidence intervals to describe the effects in individual trials, and assessed heterogeneity of these ratios between trials. MAIN RESULTS: We identified 27 eligible trials with more than 26,604 participants. There were 24 studies involving interventions aimed directly at trial participants, while three evaluated interventions aimed at people recruiting participants. All studies were in health care. Some interventions were effective in increasing recruitment: telephone reminders to non-respondents (RR 2.66, 95% CI 1.37 to 5.18), use of opt-out, rather than opt-in, procedures for contacting potential trial participants (RR 1.39, 95% CI 1.06 to 1.84) and open designs where participants know which treatment they are receiving in the trial (RR 1.25, 95% CI 1.18 to 1.34). However, some of these strategies have disadvantages, which may limit their widespread use. For example, opt-out procedures are controversial and open designs are by definition unblinded. The effects of many other recruitment strategies are unclear; examples include the use of video to provide trial information to potential participants and modifying the training of recruiters. Many studies looked at recruitment to hypothetical trials and it is unclear how applicable these results are to real trials. AUTHORS' CONCLUSIONS: Trialists can increase recruitment to their trials by using the strategies shown to be effective in this review: telephone reminders; use of opt-out, rather than opt-in; procedures for contacting potential trial participants and open designs. Some strategies (e.g. open trial designs) need to be considered carefully before use because they also have disadvantages. For example, opt-out procedures are controversial and open designs are by definition unblinded.

342 citations

Journal ArticleDOI
TL;DR: The analysis showed that self-monitoring and self-management of oral coagulation is a safe option for suitable patients of all ages and patients should also be offered the option to self-manage their disease with suitable health-care support as back-up.

342 citations

Journal ArticleDOI
TL;DR: 3D-CRT APBI increased rates of adverse cosmesis and late radiation toxicity compared with standard WBI, and Clinicians and patients are cautioned against the use of 3D- CRTAPBI outside the context of a controlled trial.
Abstract: Purpose To report interim cosmetic and toxicity results of a multicenter randomized trial comparing accelerated partial-breast irradiation (APBI) using three-dimensional conformal external beam radiation therapy (3D-CRT) with whole-breast irradiation (WBI). Patients and Methods Women age > 40 years with invasive or in situ breast cancer ≤ 3 cm were randomly assigned after breast-conserving surgery to 3D-CRT APBI (38.5 Gy in 10 fractions twice daily) or WBI (42.5 Gy in 16 or 50 Gy in 25 daily fractions ± boost irradiation). The primary outcome was ipsilateral breast tumor recurrence (IBTR). Secondary outcomes were cosmesis and toxicity. Adverse cosmesis was defined as a fair or poor global cosmetic score. After a planned interim cosmetic analysis, the data, safety, and monitoring committee recommended release of results. There have been too few IBTR events to trigger an efficacy analysis. Results Between 2006 and 2011, 2,135 women were randomly assigned to 3D-CRT APBI or WBI. Median follow-up was 36 months...

338 citations

Journal ArticleDOI
TL;DR: A systematic review of 114 randomized trials that compared placebo‐treated patients with untreated patients could not confirm that placebo interventions induce powerful effects.
Abstract: . Background. It is widely believed that placebo interventions induce powerful effects. We could not confirm this in a systematic review of 114 randomized trials that compared placebo-treated with untreated patients. Aim. To study whether a new sample of trials would reproduce our earlier findings, and to update the review. Methods. Systematic review of trials that were published since our last search (or not previously identified), and of all available trials. Results. Data was available in 42 out of 52 new trials (3212 patients). The results were similar to our previous findings. The updated review summarizes data from 156 trials (11 737 patients). We found no statistically significant pooled effect in 38 trials with binary outcomes, relative risk 0.95 (95% confidence interval 0.89–1.01). The effect on continuous outcomes decreased with increasing sample size, and there was considerable variation in effect also between large trials; the effect estimates should therefore be interpreted cautiously. If this bias is disregarded, the pooled standardized mean difference in 118 trials with continuous outcomes was −0.24 (−0.31 to −0.17). For trials with patient-reported outcomes the effect was −0.30 (−0.38 to −0.21), but only −0.10 (−0.20 to 0.01) for trials with observer-reported outcomes. Of 10 clinical conditions investigated in three trials or more, placebo had a statistically significant pooled effect only on pain or phobia on continuous scales. Conclusion. We found no evidence of a generally large effect of placebo interventions. A possible small effect on patient-reported continuous outcomes, especially pain, could not be clearly distinguished from bias.

335 citations


Authors

Showing all 2000 results

NameH-indexPapersCitations
Douglas G. Altman2531001680344
John P. A. Ioannidis1851311193612
Jasvinder A. Singh1762382223370
George A. Wells149941114256
Shah Ebrahim14673396807
Holger J. Schünemann141810113169
Paul G. Shekelle132601101639
Peter Tugwell129948125480
Jeremy M. Grimshaw123691115126
Peter Jüni12159399254
John J. McGrath120791124804
Arne Astrup11486668877
Mike Clarke1131037164328
Rachelle Buchbinder11261394973
Ian Roberts11271451933
Network Information
Related Institutions (5)
Copenhagen University Hospital
21.5K papers, 789.8K citations

88% related

VU University Medical Center
22.9K papers, 1.1M citations

88% related

University Medical Center Groningen
30.3K papers, 967K citations

88% related

World Health Organization
22.2K papers, 1.3M citations

87% related

Radboud University Nijmegen Medical Centre
12.6K papers, 659.2K citations

87% related

Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20231
202210
2021289
2020288
2019215
2018213