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Search Results: 1 - 10 of 1283 matches for " Gerd Antes "
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Registering clinical trials is necessary for ethical, scientific and economic reasons
Antes Gerd
Bulletin of the World Health Organization , 2004,
Abstract:
The demise of the randomised controlled trial: bibliometric study of the German-language health care literature, 1948 to 2004
Daniel Galandi, Guido Schwarzer, Gerd Antes
BMC Medical Research Methodology , 2006, DOI: 10.1186/1471-2288-6-30
Abstract: Eight German language general health care journals were searched for randomised controlled trials and analysed with respect to the number of published RCTs each year and the size of trials.A total of 1618 trials were identified with a median total number of 43 patients per trial. Between 1970 and 2004 a small but constant rise in sample size from a median number of 30 to 60 patients per trial can be observed. The number of published trials was very low between 1948 and 1970, but increased between 1970 and 1986 to a maximum of 11.2 RCTs per journal and year. In the following time period a striking decline of the number of RCTs was observed. Between 1999 and 2001 only 0.8 RCTs per journal and year were published, in the next three years, the number of published trials increased to 1.7 RCTs per journal and year.German language general health care journals no longer have a role in the dissemination of trial results. The slight rise in the number of published RCTs in the last three years can be explained by a change of publication language from German to English of three of the analysed journals.Approximately more than 10,000 randomised controlled trials (RCTs) – widely acknowledged as the gold standard for the evaluation of medical interventions – are published each year. Systematic reviews of RCTs, such as those disseminated through the Cochrane Collaboration, synthesise the results of individual trials to facilitate the use of external evidence in clinical decision making. The process of systematic reviewing is designed to maximise validity. This is accomplished with a series of steps to minimise bias, such as a comprehensive literature search. Indeed, the exhaustive identification of trials, irrespective of the language of publication, seems important to reduce systematic errors like language bias. Studies investigating the influence of language bias reveal controversial findings. For the comparison of German and English-language trials, a significant trend towards p
Distribution of Country of Origin in Studies Used in Cochrane Reviews
Robert F. Wolff,Stefan Reinders,Michael Barth,Gerd Antes
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0018798
Abstract: Inclusion in systematic reviews is one important component in judging the potential impact of clinical studies upon practice and hence the ‘value for money’ of spending for clinical research. This study aims to quantify the distribution of countries of origin of clinical studies used in Cochrane Reviews (CRs), and to link these data to the size of a country and to its spending on research.
Scientific Value of Systematic Reviews: Survey of Editors of Core Clinical Journals
Joerg J. Meerpohl, Florian Herrle, Gerd Antes, Erik von Elm
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0035732
Abstract: Background Synthesizing research evidence using systematic and rigorous methods has become a key feature of evidence-based medicine and knowledge translation. Systematic reviews (SRs) may or may not include a meta-analysis depending on the suitability of available data. They are often being criticised as ‘secondary research’ and denied the status of original research. Scientific journals play an important role in the publication process. How they appraise a given type of research influences the status of that research in the scientific community. We investigated the attitudes of editors of core clinical journals towards SRs and their value for publication. Methods We identified the 118 journals labelled as “core clinical journals” by the National Library of Medicine, USA in April 2009. The journals’ editors were surveyed by email in 2009 and asked whether they considered SRs as original research projects; whether they published SRs; and for which section of the journal they would consider a SR manuscript. Results The editors of 65 journals (55%) responded. Most respondents considered SRs to be original research (71%) and almost all journals (93%) published SRs. Several editors regarded the use of Cochrane methodology or a meta-analysis as quality criteria; for some respondents these criteria were premises for the consideration of SRs as original research. Journals placed SRs in various sections such as “Review” or “Feature article”. Characterization of non-responding journals showed that about two thirds do publish systematic reviews. Discussion Currently, the editors of most core clinical journals consider SRs original research. Our findings are limited by a non-responder rate of 45%. Individual comments suggest that this is a grey area and attitudes differ widely. A debate about the definition of ‘original research’ in the context of SRs is warranted.
Tamoxifen for the management of breast events induced by non-steroidal antiandrogens in patients with prostate cancer: a systematic review
Kunath Frank,Keck Bastian,Antes Gerd,Wullich Bernd
BMC Medicine , 2012, DOI: 10.1186/1741-7015-10-96
Abstract: Background Tamoxifen has emerged as a potential management option for gynecomastia and breast pain due to non-steroidal antiandrogens, and it is considered an alternative to surgery or radiotherapy. The objective of this systematic review was to assess the benefits and harms of tamoxifen, in comparison to other treatment options, for either the prophylaxis or treatment of breast events induced by non-steroidal antiandrogens in prostate cancer patients. Methods We searched CENTRAL, MEDLINE, EMBASE, reference lists, the abstracts of three major conferences and three trial registers to identify ongoing randomized controlled trials (RCTs). Two authors independently screened the articles identified, assessed the trial quality and extracted data. The protocol was prospectively registered (CRD42011001320; http://www.crd.york.ac.uk/PROSPERO). Results Four studies were identified. Tamoxifen significantly reduced the risk of suffering from gynecomastia (risk ratio 9RR0 0.10, 95% CI 0.05 to 0.22) or breast pain (RR 0.06, 95% CI 0.02 to 0.17) at six months compared to untreated controls. Tamoxifen also showed a significant benefit for the prevention of gynecomastia (RR 0.22, 95% CI 0.08 to 0.58) and breast pain (RR 0.25, 95% CI 0.10 to 0.64) when compared to anastrozole after a median of 12 months. One study showed a significant benefit of tamoxifen for the prevention of gynecomastia (RR 0.24, 95% CI 0.09 to 0.65) and breast pain (RR 0.20, 95% CI 0.06 to 0.65) when compared with radiotherapy at six months. Radiotherapy increased the risk of suffering from nipple erythema and skin irritation, but there were no significant differences for any other adverse events (all P > 0.05). Conclusions The currently available evidence suggests good efficacy of tamoxifen for the prevention and treatment of breast events induced by non-steroidal antiandrogens. The impact of tamoxifen therapy on long-term adverse events, disease progression and survival remains unclear. Further large, well-designed RCTs, including long-term follow-ups, are warranted. Also, the optimal dose needs to be clarified.
Have Online International Medical Journals Made Local Journals Obsolete?
David Ofori-Adjei,Gerd Antes,Prathap Tharyan,Elizabeth Slade,Pritpal S Tamber
PLOS Medicine , 2006, DOI: 10.1371/journal.pmed.0030359
Abstract: Background to the Debate All of the major international medical journals are now available both in print and online. Being online increases the potential for these journals to have a more global distribution. With the rise of these online international journals, what functions do local journals serve?.
A Safety Review and Meta-Analyses of Bevacizumab and Ranibizumab: Off-Label versus Goldstandard
Christine Schmucker, Christoph Ehlken, Hansjuergen T. Agostini, Gerd Antes, Gerta Ruecker, Monika Lelgemann, Yoon K. Loke
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0042701
Abstract: Background We set out a systemic review to evaluate whether off-label bevacizumab is as safe as licensed ranibizumab, and whether bevacizumab can be justifiably offered to patients as a treatment for age-related macular degeneration with robust evidence of no differential risk. Methods and Findings Medline, Embase and the Cochrane Library were searched with no limitations of language and year of publication. We included RCTs with a minimum follow-up of one year which investigated bevacizumab or ranibizumab in direct comparison or against any other control group (indirect comparison). Direct comparison (3 trials, 1333 patients): The one year data show a significantly higher rate of ocular adverse effects (AE) with bevacizumab compared to ranibizumab (RR = 2.8; 95% CI 1.2–6.5). The proportion of patients with serious infections and gastrointestinal disorders was also higher with bevacizumab than with ranibizumab (RR = 1.3; 95% CI 1.0–1.7). Arterial thromboembolic events were equally distributed among the groups. Indirect comparison: Ranibizumab versus any control (5 trials, 4054 patients): The two year results of three landmark trials showed that while absolute rates of serious ocular AE were low (≤2.1%), relative harm was significantly raised (RR = 3.1; 95% CI 1.1–8.9). A significant increase in nonocular haemorrhage was also observed with ranibizumab (RR = 1.7; 95% CI 1.1–2.7). Bevacizumab versus any control (3 trials, 244 patients): We were unable to judge the safety profile of bevacizumab due to the poor quality of AE monitoring and reporting in the trials. Conclusions Evidence from head-to-head trials raises concern about an increased risk of ocular and multiple systemic AE with bevacizumab. Therefore, clinicians and patients should continue to carefully weight up the benefits and harms when choosing between the two treatment options. We also emphasize the need for studies that are powered not just for efficacy, but for defined safety outcomes based on the signals detected in this systematic review.
Are pediatric Open Access journals promoting good publication practice? An analysis of author instructions
Joerg J Meerpohl, Robert F Wolff, Gerd Antes, Erik von Elm
BMC Pediatrics , 2011, DOI: 10.1186/1471-2431-11-27
Abstract: We identified 41 journals publishing original research in the subject category "Health Sciences, Medicine (General), Pediatrics" of the Directory of Open Access Journals http://www.doaj.org webcite. From the journals' online author instructions we extracted information regarding endorsement of four domains of editorial policy: the Uniform Requirements for Manuscripts, trial registration, disclosure of conflicts of interest and five major reporting guidelines such as the CONSORT (Consolidated Standards of Reporting Trials) statement. Two investigators collected data independently.The Uniform Requirements were mentioned by 27 (66%) pediatric OA journals. Thirteen (32%) required or recommended trial registration prior to publication of a trial report. Conflict of interest policies were stated by 25 journals (61%). Advice about reporting guidelines was less frequent: CONSORT was referred to by 12 journals (29%) followed by other reporting guidelines (MOOSE, PRISMA or STARD) (8 journals, 20%) and STROBE (3 journals, 7%). The EQUATOR network, a platform of several guideline initiatives, was acknowledged by 4 journals (10%).Journals published by OA publishing houses gave more guidance than journals published by professional societies or other publishers.Pediatric OA journals mentioned certain recommendations such as the Uniform Requirements or trial registration more frequently than conventional journals; however, endorsement is still only moderate. Further research should confirm these exploratory findings in other medical fields and should clarify what the motivations and barriers are in implementing such policies.Medical research reports and publication practice in biomedicine have been under increased scrutiny over the last decades. Selective reporting of study results and related publication bias has been confirmed in several empirical studies in different disciplines and settings[1]. Further, there is continued concern regarding conflicts of interest that are not dis
Effectiveness of screening preschool children for amblyopia: a systematic review
Christine Schmucker, Robert Grosselfinger, Rob Riemsma, Gerd Antes, Stefan Lange, Wolf Lagrèze, Jos Kleijnen
BMC Ophthalmology , 2009, DOI: 10.1186/1471-2415-9-3
Abstract: Ten bibliographic databases were searched for randomised controlled trials, non-randomised controlled trials and cohort studies with no limitations to a specific year of publication and language. The searches were supplemented by handsearching the bibliographies of included studies and reviews to identify articles not captured through our main search strategy.Five studies met the inclusion criteria. Of these, three studies suggested that screening is associated with an absolute reduction in the prevalence of amblyopia between 0.9% and 1.6% (relative reduction: between 45% and 62%). However, the studies showed weaknesses, limiting the validity and reliability of their findings. The main limitation was that studies with significant results considered only a proportion of the originally recruited children in their analysis. On the other hand, retrospective sample size calculation indicated that the power based on the cohort size was not sufficient to detect small changes between the groups. Outcome parameters such as quality of life or adverse effects of screening have not been adequately investigated in the literature currently available.Population based preschool vision screening programmes cannot be sufficiently assessed by the literature currently available. However, it is most likely that the present systematic review contains the most detailed description of the main limitations in current available literature evaluating these programmes. Therefore, future research work should be guided by the findings of this publication.Amblyopia is a reversible visual deficit that develops during the maturation of the visual system (which is usually considered to be up to seven years of age) and may affect one or both eyes [1-3]. Risk factors associated with amblyopia are strabismus (a misalignment of the eyes) and uncorrected refractive errors, in particular anisometropia (unequal refractive errors between the two eyes) [4,5]. Congenital cataract, congenital ptosis and cornea
All Nations Depend on the Global Knowledge Pool – Analysis of Country of Origin of Studies Used for Health Technology Assessments in Germany
Kirsten H. Herrmann, Robert Wolff, Fueloep Scheibler, Siw Waffenschmidt, Lars G. Hemkens, Stefan Sauerland, Gerd Antes
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0059213
Abstract: Background Health Technology Assessments (HTAs) are used to inform decision-making and their usefulness depends on the quality and relevance of research and specific studies for health-policy decisions. Little is known about the country of origin of studies used for HTAs. Objective To investigate which countries have made the largest contributions to inform health policy decisions through studies included in HTAs in Germany. Methods The country of origin was extracted from all studies included in HTAs of the German Institute for Quality and Efficiency in Health Care, (IQWiG), published from 2/2006 to 9/2010. Studies were ranked according to the total number of studies per country, adjusted for population size, gross domestic product (GDP), and total health expenditure. Results 1087 studies were included in 54 HTA reports. Studies were assigned to 45 countries. Most of the studies (27%) originated from the United States (USA), 18% were multinational, followed by 7% from the United Kingdom (UK) and 5% from Germany. Nordic countries led the ranking when adjusting for population size/million (ranks 1-3,6,9/45 countries), GDP/billion US$ (1,2,5,9,14/45), or health expenditure/billion US$ (1,3,5,12,13/45). The relative contribution of the UK was stable in the analyses when adjusted for population size (7/45), GDP (7/45), and health expenditure (9/45), whereas the USA (13, 18, and 30/45) and Germany (17, 19, and 21/45) dropped in the ranking. Conclusions More than half of the studies relevant for evidence-informed decision-making in Germany originated from the USA, followed by multinational research and the UK. Only 5% of the studies originated from Germany. According to our findings, there appears to be some discrepancy between the use of globally generated evidence and the contribution to the knowledge pool by individual countries.
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