Showing papers by "Cochrane Collaboration published in 2007"

The Strengthening the Reporting of Observational Studies in Epidemiology [STROBE] statement: guidelines for reporting observational studies

Abstract: Much biomedical research is observational. The reporting of such research is often inadequate, which hampers the assessment of its strengths and weaknesses and of a study's generalisability. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Initiative developed recommendations on what should be included in an accurate and complete report of an observational study. We defined the scope of the recommendations to cover three main study designs: cohort, case-control, and cross-sectional studies. We convened a 2-day workshop in September 2004, with methodologists, researchers, and journal editors to draft a checklist of items. This list was subsequently revised during several meetings of the coordinating group and in e-mail discussions with the larger group of STROBE contributors, taking into account empirical evidence and methodological considerations. The workshop and the subsequent iterative process of consultation and revision resulted in a checklist of 22 items (the STROBE Statement) that relate to the title, abstract, introduction, methods, results, and discussion sections of articles. 18 items are common to all three study designs and four are specific for cohort, case-control, or cross-sectional studies. A detailed Explanation and Elaboration document is published separately and is freely available on the Web sites of PLoS Medicine, Annals of Internal Medicine, and Epidemiology. We hope that the STROBE Statement will contribute to improving the quality of reporting of observational studies.

The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies

Abstract: Much biomedical research is observational. The reporting of such research is often inadequate, which hampers the assessment of its strengths and weaknesses and of a study’s generalizability. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Initiative developed recommendations on what should be included in an accurate and complete report of an observational study. We defined the scope of the recommendations to cover three main study designs: cohort, case-control and cross-sectional studies. We convened a two-day workshop, in September 2004, with methodologists, researchers and journal editors to draft a checklist of items. This list was subsequently revised during several meetings of the coordinating group and in e-mail discussions with the larger group of STROBE contributors, taking into account empirical evidence and methodological considerations. The workshop and the subsequent iterative process of consultation and revision resulted in a checklist of 22 items (the STROBE Statement) that relate to the title, abstract, introduction, methods, results and discussion sections of articles. Eighteen items are common to all three study designs and four are specific for cohort, case-control, or cross-sectional studies. A detailed Explanation and Elaboration document is published separately and is freely available on the web sites of PLoS Medicine, Annals of Internal Medicine and Epidemiology. We hope that the STROBE Statement will contribute to improving the quality of reporting of observational studies.

The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: Guidelines for Reporting Observational Studies

Abstract: Much biomedical research is observational. The reporting of such research is often inadequate, which hampers the assessment of its strengths and weaknesses and of a study's generalizability. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Initiative developed recommendations on what should be included in an accurate and complete report of an observational study. We defined the scope of the recommendations to cover 3 main study designs: cohort, case-control, and cross-sectional studies. We convened a 2-day workshop in September 2004, with methodologists, researchers, and journal editors, to draft a checklist of items. This list was subsequently revised during several meetings of the coordinating group and in e-mail discussions with the larger group of STROBE contributors, taking into account empirical evidence and methodological considerations. The workshop and the subsequent iterative process of consultation and revision resulted in a checklist of 22 items (the STROBE Statement) that relate to the title, abstract, introduction, methods, results, and discussion sections of articles. Eighteen items are common to all 3 study designs and 4 are specific for cohort, case-control, or cross-sectional studies. A detailed Explanation and Elaboration document is published separately and is freely available at http://www.annals.org and on the Web sites of PLoS Medicine and Epidemiology. We hope that the STROBE Statement will contribute to improving the quality of reporting of observational studies.

Patient Adherence to Tuberculosis Treatment: A Systematic Review of Qualitative Research

Abstract: Background Tuberculosis (TB) is a major contributor to the global burden of disease and has received considerable attention in recent years, particularly in low- and middle-income countries where it is closely associated with HIV/AIDS. Poor adherence to treatment is common despite various interventions aimed at improving treatment completion. Lack of a comprehensive and holistic understanding of barriers to and facilitators of, treatment adherence is currently a major obstacle to finding effective solutions. The aim of this systematic review of qualitative studies was to understand the factors considered important by patients, caregivers and health care providers in contributing to TB medication adherence.

The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies.

Abstract: Much biomedical research is observational. The reporting of such research is often inadequate, which hampers the assessment of its strengths and weaknesses and of a study's generalizability. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Initiative developed recommendations on what should be included in an accurate and complete report of an observational study. We defined the scope of the recommendations to cover three main study designs: cohort, case-control and cross-sectional studies. We convened a 2-day workshop in September 2004, with methodologists, researchers, and journal editors to draft a checklist of items. This list was subsequently revised during several meetings of the coordinating group and in e-mail discussions with the larger group of STROBE contributors, taking into account empirical evidence and methodological considerations. The workshop and the subsequent iterative process of consultation and revision resulted in a checklist of 22 items (the STROBE Statement) that relate to the title, abstract, introduction, methods, results, and discussion sections of articles. 18 items are common to all three study designs and four are specific for cohort, case-control, or cross-sectional studies. A detailed "Explanation and Elaboration" document is published separately and is freely available on the web sites of PLoS Medicine, Annals of Internal Medicine, and Epidemiology. We hope that the STROBE Statement will contribute to improving the quality of reporting of observational studies.

A review of health behaviour theories: how useful are these for developing interventions to promote long-term medication adherence for TB and HIV/AIDS?

Abstract: Suboptimal treatment adherence remains a barrier to the control of many infectious diseases, including tuberculosis and HIV/AIDS, which contribute significantly to the global disease burden. However, few of the many interventions developed to address this issue explicitly draw on theories of health behaviour. Such theories could contribute to the design of more effective interventions to promote treatment adherence and to improving assessments of the transferability of these interventions across different health issues and settings. This paper reviews behaviour change theories applicable to long-term treatment adherence; assesses the evidence for their effectiveness in predicting behaviour change; and examines the implications of these findings for developing strategies to improve TB and HIV/AIDS medication adherence. We searched a number of electronic databases for theories of behaviour change. Eleven theories were examined. Little empirical evidence was located on the effectiveness of these theories in promoting adherence. However, several models have the potential to both improve understanding of adherence behaviours and contribute to the design of more effective interventions to promote adherence to TB and HIV/AIDS medication. Further research and analysis is needed urgently to determine which models might best improve adherence to long-term treatment regimens.

Grey literature in meta‐analyses of randomized trials of health care interventions

Abstract: BACKGROUND: The inclusion of grey literature (i.e. literature that has not been formally published) in systematic reviews may help to overcome some of the problems of publication bias, which can arise due to the selective availability of data. OBJECTIVES: To review systematically research studies, which have investigated the impact of grey literature in meta-analyses of randomized trials of health care interventions. SEARCH STRATEGY: We searched the Cochrane Methodology Register (The Cochrane Library Issue 3, 2005), MEDLINE (1966 to 20 May 2005), the Science Citation Index (June 2005) and contacted researchers who may have carried out relevant studies. SELECTION CRITERIA: A study was considered eligible for this review if it compared the effect of the inclusion and exclusion of grey literature on the results of a cohort of meta-analyses of randomized trials. DATA COLLECTION AND ANALYSIS: Data were extracted from each report independently by two reviewers. The main outcome measure was an estimate of the impact of trials from the grey literature on the pooled effect estimates of the meta-analyses. Information was also collected on the area of health care, the number of meta-analyses, the number of trials, the number of trial participants, the year of publication of the trials, the language and country of publication of the trials, the number and type of grey and published literature, and methodological quality. MAIN RESULTS: Five studies met the inclusion criteria. All five studies showed that published trials showed an overall greater treatment effect than grey trials. This difference was statistically significant in one of the five studies. Data could be combined for three of the five studies. This showed that, on average, published trials showed a 9% greater treatment effect than grey trials (ratio of odds ratios for grey versus published trials 1.09; 95% CI 1.03-1.16). Overall there were more published trials included in the meta-analyses than grey trials (median 224 (IQR 108-365) versus 45(IQR 40-102)). Published trials had more participants on average. The most common types of grey literature were abstracts (55%) and unpublished data (30%). There is limited evidence to show whether grey trials are of poorer methodological quality than published trials. AUTHORS' CONCLUSIONS: This review shows that published trials tend to be larger and show an overall greater treatment effect than grey trials. This has important implications for reviewers who need to ensure they identify grey trials, in order to minimise the risk of introducing bias into their review.

Methods to increase response rates to postal questionnaires

Abstract: Background: Postal questionnaires are widely used for data collection in epidemiological studies but non-response reduces the effective sample size and can introduce bias. Finding ways to increase response rates to postal questionnaires would improve the quality of health research. Objectives: To identify effective strategies to increase response rates to postal questionnaires. Search strategy: We aimed to find all randomised controlled trials of strategies to increase response rates to postal questionnaires. We searched 14 electronic databases to February 2003 and manually searched the reference lists of relevant trials and reviews, and all issues of two journals. We contacted the authors of all trials or reviews to ask about unpublished trials. Where necessary, authors were also contacted to confirm methods of allocation used and to clarify results presented. We assessed the eligibility of each trial using pre-defined criteria. Selection criteria: Randomised controlled trials of methods to increase response rates to postal questionnaires. Data collection and analysis: We extracted data on the trial participants, the intervention, the number randomised to intervention and comparison groups and allocation concealment. For each strategy, we estimated pooled odds ratios and 95% confidence intervals in a random effects model. Evidence for selection bias was assessed using Egger's weighted regression method and Begg's rank correlation test and funnel plot. Heterogeneity among trial odds ratios was assessed using a chi-square test at a 5% significance level and the degree of inconsistency between trial results was quantified using I2. Main results: We found 372 eligible trials. The trials evaluated 98 different ways of increasing response rates to postal questionnaires and for 62 of these the combined trials included over 1,000 participants. We found substantial heterogeneity among trial results in half of the strategies. The odds of response were at least doubled using monetary incentives (odds ratio 1.99, 95% CI 1.81 to 2.18; heterogeneity p < 0.00001, I 2 =78%), recorded delivery (2.04, 1.60 to 2.61; p=0.0004, I 2 =69%), a teaser on the envelope - e.g. a comment suggesting to participants that they may benefit if they open it (3.08, 1.27 to 7.44) and a more interesting questionnaire topic (2.44, 1.99 to 3.01; p=0.74, I 2 =0%). The odds of response were substantially higher with pre-notification (1.50, 1.29 to 1.74; p < 0.00001, I 2 =90%), follow-up contact (1.44, 1.25 to 1.65; p < 0.0001, I 2 =68%), unconditional incentives (1.61, 1.27 to 2.04; p < 0.00001, I 2 =91%), shorter questionnaires (1.73, 1.47 to 2.03; p < 0.00001, I 2 =93%), providing a second copy of the questionnaire at follow-up (1.51, 1.13 to 2.00; p < 0.00001, I 2 =83%), mentioning an obligation to respond (1.61, 1.16 to 2.22; p=0.98, I 2 =0%) and university sponsorship (1.32, 1.13 to 1.54; p < 0.00001, I 2 =83%). The odds of response were also increased with non-monetary incentives (1.13, 1.07 to 1.21; p < 0.00001, I 2 =71%), personalised questionnaires (1.16, 1.07 to 1.26; p < 0.00001, I 2 =67%), use of coloured as opposed to blue or black ink (1.39, 1.16 to 1.67), use of stamped return envelopes as opposed to franked return envelopes (1.29, 1.18 to 1.42; p < 0.00001, I 2 =72%), an assurance of confidentiality (1.33, 1.24 to 1.42) and first class outward mailing (1.12, 1.02 to 1.23). The odds of response were reduced when the questionnaire included questions of a sensitive nature (0.94, 0.88 to 1.00; p=0.51, I 2 =0%), when questionnaires began with the most general questions (0.80, 0.67 to 0.96), or when participants were offered the opportunity to opt out of the study (0.76, 0.65 to 0.89; p=0.46, I 2 =0%). Authors' conclusions: Health researchers using postal questionnaires can increase response rates using the strategies shown to be effective in this systematic review. Copyright © 2008 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.

Impact of allocation concealment on conclusions drawn from meta-analyses of randomized trials

Abstract: Background Randomized trials without reported adequate allocation concealment have been shown to overestimate the benefit of experimental interventions. We investigated the robustness of conclusions drawn from meta-analyses to exclusion of such trials. Material Random sample of 38 reviews from The Cochrane Library 2003, issue 2 and 32 other reviews from PubMed accessed in 2002. Eligible reviews presented a binary effect estimate from a meta-analysis of randomized controlled trials as the first statistically significant result that supported a conclusion in favour of one of the interventions. Methods We assessed the methods sections of the trials in each included meta-analysis for adequacy of allocation concealment. We replicated each meta-analysis using the authors' methods but included only trials that had adequate allocation concealment. Conclusions were defined as not supported if our result was not statistically significant. Results Thirty-four of the 70 meta-analyses contained a mixture of trials with unclear or inadequate concealment as well as trials with adequate allocation concealment. Four meta-analyses only contained trials with adequate concealment, and 32, only trials with unclear or inadequate concealment. When only trials with adequate concealment were included, 48 of 70 conclusions (69%; 95% confidence interval: 56-79%) lost support. The loss of support mainly reflected loss of power (the total number of patients was reduced by 49%) but also a shift in the point estimate towards a less beneficial effect. Conclusion Two-thirds of conclusions in favour of one of the interventions were no longer supported if only trials with adequate allocation concealment were included.

School feeding for improving the physical and psychosocial health of disadvantaged students

Abstract: Early malnutrition and/or micronutrient deficiencies can negatively affect many aspects of child health and development. School feeding programs are designed to provide food to hungry children and to improve their physical, mental and psychosocial health. This is the first systematic review on the topic of school feeding. Eighteen studies were included in this review; nine were performed in higher income countries and nine in lower income countries. In the highest quality studies (randomized controlled trials (RCTs) from low income countries, children who were fed at school gained an average of 0.39 kg more than controls over 19 months; in lower quality studies (controlled before and after trials (CBAs)), the difference in gain was 0.71 kg over 11.3 months. Children who were fed at school attended school more frequently than those in control groups; this finding translated to an average increase of 4 to 6 days a year per child. For educational and cognitive outcomes, children who were fed at school gained more than controls on math achievement, and on some short-term cognitive tasks.

Reporting methods of blinding in randomized trials assessing nonpharmacological treatments.

Abstract: Background Blinding is a cornerstone of treatment evaluation. Blinding is more difficult to obtain in trials assessing nonpharmacological treatment and frequently relies on ‘‘creative’’ (nonstandard) methods. The purpose of this study was to systematically describe the strategies used to obtain blinding in a sample of randomized controlled trials of nonpharmacological treatment.

The ORION statement: guidelines for transparent reporting of outbreak reports and intervention studies of nosocomial infection

Abstract: The quality of research in hospital epidemiology (infection control) must be improved to be robust enough to influence policy and practice. In order to raise the standards of research and publication, a CONSORT equivalent for these largely quasi-experimental studies has been prepared by the authors of two relevant systematic reviews, following consultation with learned societies, editors of journals, and researchers. The ORION (Outbreak Reports and Intervention Studies Of Nosocomial infection) statement consists of a 22 item checklist, and a summary table. The emphasis is on transparency to improve the quality of reporting and on the use of appropriate statistical techniques. The statement has been endorsed by a number of professional special interest groups and societies. Like CONSORT, ORION should be considered a "work in progress", which requires ongoing dialogue for successful promotion and dissemination. The statement is therefore offered for further public discussion. Journals and research councils are strongly recommended to incorporate it into their submission and reviewing processes. Feedback to the authors is encouraged and the statement will be revised in 2 years.

Editorial peer review for improving the quality of reports of biomedical studies

Abstract: Background Scientific findings must withstand critical review if they are to be accepted as valid, and editorial peer review (critique, effort to disprove) is an essential element of the scientific process. We review the evidence of the editorial peer-review process of original research studies submitted for paper or electronic publication in biomedical journals. Objectives To estimate the effect of processes in editorial peer review. Search methods The following databases were searched to June 2004: CINAHL, Ovid, Cochrane Methodology Register, Dissertation abstracts, EMBASE, Evidence Based Medicine Reviews: ACP Journal Club, MEDLINE, PsycINFO, PubMed. Selection criteria We included prospective or retrospective comparative studies with two or more comparison groups, generated by random or other appropriate methods, and reporting original research, regardless of publication status. We hoped to find studies identifying good submissions on the basis of: importance of the topic dealt with, relevance of the topic to the journal, usefulness of the topic, soundness of methods, soundness of ethics, completeness and accuracy of reporting. Data collection and analysis Because of the diversity of study questions, viewpoints, methods, and outcomes, we carried out a descriptive review of included studies grouping them by broad study question. Main results We included 28 studies. We found no clear-cut evidence of effect of the well-researched practice of reviewer and/or author concealment on the outcome of the quality assessment process (9 studies). Checklists and other standardisation media have some evidence to support their use (2 studies). There is no evidence that referees' training has any effect on the quality of the outcome (1 study). Different methods of communicating with reviewers and means of dissemination do not appear to have an effect on quality (3 studies). On the basis of one study, little can be said about the ability of the peer-review process to detect bias against unconventional drugs. Validity of peer review was tested by only one small study in a specialist area. Editorial peer review appears to make papers more readable and improve the general quality of reporting (2 studies), but the evidence for this has very limited generalisability. Authors' conclusions At present, little empirical evidence is available to support the use of editorial peer review as a mechanism to ensure quality of biomedical research. However, the methodological problems in studying peer review are many and complex. At present, the absence of evidence on efficacy and effectiveness cannot be interpreted as evidence of their absence. A large, well-funded programme of research on the effects of editorial peer review should be urgently launched.

Ghost Authorship in Industry-Initiated Randomised Trials

Abstract: Background Ghost authorship, the failure to name, as an author, an individual who has made substantial contributions to an article, may result in lack of accountability. The prevalence and nature of ghost authorship in industry-initiated randomised trials is not known. Methods and Findings We conducted a cohort study comparing protocols and corresponding publications for industry-initiated trials approved by the Scientific-Ethical Committees for Copenhagen and Frederiksberg in 1994–1995. We defined ghost authorship as present if individuals who wrote the trial protocol, performed the statistical analyses, or wrote the manuscript, were not listed as authors of the publication, or as members of a study group or writing committee, or in an acknowledgment. We identified 44 industry-initiated trials. We did not find any trial protocol or publication that stated explicitly that the clinical study report or the manuscript was to be written or was written by the clinical investigators, and none of the protocols stated that clinical investigators were to be involved with data analysis. We found evidence of ghost authorship for 33 trials (75%; 95% confidence interval 60%–87%). The prevalence of ghost authorship was increased to 91% (40 of 44 articles; 95% confidence interval 78%–98%) when we included cases where a person qualifying for authorship was acknowledged rather than appearing as an author. In 31 trials, the ghost authors we identified were statisticians. It is likely that we have overlooked some ghost authors, as we had very limited information to identify the possible omission of other individuals who would have qualified as authors. Conclusions Ghost authorship in industry-initiated trials is very common. Its prevalence could be considerably reduced, and transparency improved, if existing guidelines were followed, and if protocols were publicly available.

Time to publication for results of clinical trials

Abstract: Background It has been suggested that a time-lag bias exists whereby research studies with striking results are more likely to be stopped earlier than originally planned, published quicker, or both. If time-lag bias exists, new interventions might be mistakenly assumed to be effective. Objectives To study the extent to which time to publication of a clinical trial is influenced by the significance of its result. Search methods Studies were identified by searching the Cochrane Methodology Register (The Cochrane Library, Issue 3, 2005), MEDLINE (1966 to May 2005), EMBASE (1980 to May 2005), Science Citation Index (June 2005) and by handsearching journals and conference abstracts. Selection criteria Studies were eligible if they contained analyses of any aspect of the time to publication of clinical trials and tracked the publication of a cohort of clinical trials. Data collection and analysis Data extraction was performed independently by two authors. Data were extracted on the median time from the date the trial started to the date of publication. Data were also extracted on source of trials under investigation; source of funding; area of health care; means by which the publication status of these trials were sought; and methodological quality of the empirical study. Main results Two studies with a total of 196 trials met the inclusion criteria. In both studies just over half of all trials had been published in full. Trials with positive results (i.e. statistically significant in favour of the experimental arm) were published in approximately 4 to 5 years. Trials with null or negative results (i.e. not statistically significant or statistically significant in favour of the control arm) were published after about 6 to 8 years. One study suggested that this difference could, in part, be attributed to the length of time taken to publish the results of a trial once follow up has been completed. This study showed that trials with null or negative findings took, on average, just over a year longer to be published than those with positive results. Authors' conclusions Our review shows that trials with positive results are published sooner than other trials. This has important implications for the timing of the initiation and updating of a review, especially if there is an association between the inclusion of a trial in a review and its publication status. It is of particular concern when one considers reviews containing only a small number of studies.

Phytoestrogens for vasomotor menopausal symptoms.

Abstract: Background Vasomotor symptoms, such as hot flushes and night sweats, are very common during the menopausal transition. Hormone replacement therapy has traditionally been used as a very effective treatment but concerns over increased risks of some chronic diseases have markedly increased the interest of women in alternatives. Some of the most popular of these are treatments based on foods or supplements enriched with phytoestrogens, plant-derived chemicals that have oestrogenic action. Objectives To assess the efficacy, safety and acceptability of foods and supplements based on high levels of phytoestrogens for reducing hot flushes and night sweats in postmenopausal women. Search methods Searches were undertaken of the following electronic databases: the Cochrane Menstrual Disorders and Subfertility Group Specialised Register of randomised trials, Cochrane Register of Controlled Trials (CENTRAL) (March 2007), MEDLINE (1966 to March 2007), EMBASE (1980 to March 2007), AMED (1985 to March 2007), PsycINFO (1986 to March 2007) and CINAHL (1982 to March 2007). Attempts were made to access grey literature by letters to pharmaceutical companies and searches of ongoing trial registers. Reference lists of included trials were also searched. Selection criteria Studies were included if they were randomised, had peri- or postmenopausal participants with vasomotor symptoms, a duration of at least 12 weeks and where the intervention was a food or supplement with high levels of phytoestrogens (and not combined with other herbal treatments). Trials of women who had breast cancer or a history of breast cancer were excluded. Data collection and analysis Selection of trials, data extraction and quality assessment were undertaken by at least two authors. Most of the trials were too dissimilar to combine in meta-analysis and their results are provided in table format. Studies were grouped into broad categories: dietary soy, soy extracts, red clover extracts and other types of phytoestrogen. Five trials used Promensil, a red clover extract; these trials were combined in a meta-analysis and summary effect measures were calculated. Main results Thirty trials comparing phytoestrogens with control met the inclusion criteria. Very few trials had data suitable for combining in meta-analysis. Of the five trials with data suitable for pooling that assessed daily frequency of hot flushes, there was no significant difference overall in the frequency of hot flushes between Promensil (a red clover extract) and placebo (WMD=-0.6, 95% CI -1.8 to 0.6). There was no evidence of a difference in percentage reduction in hot flushes in two trials between Promensil and placebo (WMD=20.2, 95% CI -12.1 to 52.4). Individual results from the remaining trials were compared. Some of the trials found that phytoestrogen treatments alleviated the frequency and severity of hot flushes and night sweats when compared to placebo but many of the trials were of low quality and were underpowered. There was a strong placebo effect in most trials with a reduction in frequency ranging from 1% to 59% with placebo. There was no indication that the discrepant results were due to the amount of isoflavone in the active treatment arm, the severity of vasomotor symptoms or trial quality factors. There was also no evidence that the treatments caused oestrogenic stimulation of the endometrium (an adverse effect) when used for up to two years. Authors' conclusions There is no evidence of effectiveness in the alleviation of menopausal symptoms with the use of phytoestrogen treatments.

Handsearching versus electronic searching to identify reports of randomized trials.

Abstract: Background Systematic reviewers need to decide how best to reduce bias in identifying studies for their review. Even when journals are indexed in electronic databases, it can still be difficult to identify all relevant studies reported in these journals. Over 1700 journals have been or are being handsearched within The Cochrane Collaboration to identify reports of controlled trials in order to help address these problems. Objectives To review systematically empirical studies, which have compared the results of handsearching with the results of searching one or more electronic databases to identify reports of randomized trials. Search strategy Studies were sought from The Cochrane Methodology Register (The Cochrane Library, Issue 2, 2002), MEDLINE (1966 to Week 1 July 2002), EMBASE (1980 to Week 25 2002), AMED (1985 to June 2002), BIOSIS (1985 to June 2002), CINAHL (1982 to June 2002), LISA (1969 to July 2002) and PsycINFO (1972 to May 2002). Researchers who may have carried out relevant studies were contacted. Selection criteria A research study was considered eligible for this review if it compared handsearching with searching one or more electronic databases to identify reports of randomized trials. Data collection and analysis The main outcome measure was the number of reports of randomized trials identified by handsearching as compared to electronic searching. Data were extracted on the electronic database searched, the complexity of electronic search strategy used, the characteristics of the journal reports identified, and the type of trial report identified. Main results Thirty-four studies were included. Handsearching identified between 92% to 100% of the total number of reports of randomized trials found in the various comparisons in this review. Searching MEDLINE retrieved 55%, EMBASE 49% and PyscINFO 67%. The retrieval rate of the electronic database varied depending on the complexity of the search. The Cochrane Highly Sensitive Search Strategy (HSSS) identified 80% of the total number of reports of randomized trials found, searches categorised as 'complex' (including the Cochrane HSSS) found 65% and 'simple' found 42%. The retrieval rate for an electronic search was higher when the search was restricted to English language journals; 62% versus 39% for journals published in languages other than English. When the search was restricted to full reports of randomized trials, the retrieval rate for an electronic search improved: a complex search strategy (including the Cochrane HSSS) retrieved 82% of the total number of such reports of randomized trials. Authors' conclusions Handsearching still has a valuable role to play in identifying reports of randomized trials for inclusion in systematic reviews of health care interventions, particularly in identifying trials reported as abstracts, letters and those published in languages other than English, together with all reports published in journals not indexed in electronic databases. However, where time and resources are limited, searching an electronic database using a complex search (or the Cochrane HSSS) will identify the majority of trials published as full reports in English language journals, provided, of course, that the relevant journals have been indexed in the database.

Changes in landscape composition influence the decline of a threatened woodland caribou population.

Abstract: Summary 1 Large-scale habitat loss is frequently identified with loss of biodiversity, but examples of the direct effect of habitat alterations on changes in vital rates remain rare. Quantifying and understanding the relationship between habitat composition and changes in vital rates, however, is essential for the development of effective conservation strategies. 2 It has been suggested that the decline of woodland caribou Rangifer tarandus caribou populations in North America is precipitated by timber harvesting that creates landscapes of early seral forests. Such habitat changes have altered the predator–prey system resulting in asymmetric predation, where predators are maintained by alternative prey (i.e. apparent competition). However, a direct link between habitat condition and caribou population declines has not been documented. 3 We estimated survival probabilities for the threatened arboreal lichen-feeding ecotype of woodland caribou in British Columbia, Canada, at two different spatial scales. At the broader scale, observed variation in adult female survival rates among 10 distinct populations (range = 0·67–0·93) was best explained by variation in the amount of early seral stands within population ranges and population density. At the finer scale, home ranges of caribou killed by predators had lower proportions of old forest and more mid-aged forest as compared with multi-annual home ranges where caribou were alive. 4 These results are consistent with predictions from the apparent competition hypothesis and quantify direct fitness consequences for caribou following habitat alterations. We conclude that apparent competition can cause rapid population declines and even extinction where changes in species composition occur following large scale habitat change.

Data extraction errors in meta-analyses that use standardized mean differences.

Abstract: ContextMeta-analysis of trials that have used different continuous or rating scales to record outcomes of a similar nature requires sophisticated data handling and data transformation to a uniform scale, the standardized mean difference (SMD). It is not known how reliable such meta-analyses are.ObjectiveTo study whether SMDs in meta-analyses are accurate.Data SourcesSystematic review of meta-analyses published in 2004 that reported a result as an SMD, with no language restrictions. Two trials were randomly selected from each meta-analysis. We attempted to replicate the results in each meta-analysis by independently calculating SMD using Hedges adjusted g.Data ExtractionOur primary outcome was the proportion of meta-analyses for which our result differed from that of the authors by 0.1 or more, either for the point estimate or for its confidence interval, for at least 1 of the 2 selected trials. We chose 0.1 as cut point because many commonly used treatments have an effect of 0.1 to 0.5, compared with placebo.ResultsOf the 27 meta-analyses included in this study, we could not replicate the result for at least 1 of the 2 trials within 0.1 in 10 of the meta-analyses (37%), and in 4 cases, the discrepancy was 0.6 or more for the point estimate. Common problems were erroneous number of patients, means, standard deviations, and sign for the effect estimate. In total, 17 meta-analyses (63%) had errors for at least 1 of the 2 trials examined. For the 10 meta-analyses with errors of at least 0.1, we checked the data from all the trials and conducted our own meta-analysis, using the authors' methods. Seven of these 10 meta-analyses were erroneous (70%); 1 was subsequently retracted, and in 2 a significant difference disappeared or appeared.ConclusionsThe high proportion of meta-analyses based on SMDs that show errors indicates that although the statistical process is ostensibly simple, data extraction is particularly liable to errors that can negate or even reverse the findings of the study. This has implications for researchers and implies that all readers, including journal reviewers and policy makers, should approach such meta-analyses with caution.

Blinded trials taken to the test: an analysis of randomized clinical trials that report tests for the success of blinding

Abstract: Results Thirty-one out of 1599 trials (2%) reported tests for the success of blinding. Test methods varied, and reporting was generally incomplete. Blinding was considered successful in 14 out of the 31 trials (45%) and unclear in 10 (32%). Of the seven trials (23%) reporting unsuccessful blinding the risk of a biased trial result was either not addressed or was discounted in six cases. We received 130 questionnaires from trial authors (65%) of which 15 (12%) informed that they had conducted, but not published, tests. Conclusions Blinding is rarely tested. Test methods vary, and the reporting of tests, and test results, is incomplete. There is a considerable methodological uncertainty how best to assess blinding, and an urgent need for improved methodology and improved reporting.

P53 codon 72 polymorphism and gastric cancer: A meta‐analysis of the literature

Abstract: Studies investigating the association between p53 codon 72 polymorphism and gastric cancer risk report conflicting results. The objective of this study was to quantitatively summarize the evidence for such a relationship. Two investigators independently searched the Medline and Embase databases. This meta-analysis included 12 case-control studies, which included 1,665 gastric cancer cases and 2,358 controls. The combined results based on all studies showed that there was no significant difference in genotype distribution [Arg/Arg odds ratio (OR) = 0.96, 95% confidence interval (CI) = 0.79, 1.16; Pro/Pro (OR = 1.21, 95% CI = 0.92, 1.58); Pro/Arg (OR = 0.95, 95% CI = 0.79, 1.14)] between gastric cancer and noncancer patients. When stratifying for race, results were similar except that patients with gastric cancer had a significantly lower frequency of Arg/Arg (OR = 0.84, 95% CI = 0.72, 0.99) than noncancer patients among Asians. Stratified the various studies by the location, stage, Lauren's classification, and histological differentiation of gastric cancer, we found that (i) patients with cardia gastric cancer had a significantly higher frequency of Pro/Pro (OR = 3.20, 95% CI = 1.46,7.01) than those with noncardia gastric cancer among Asians; (ii) patients with advanced (stage III/IV) gastric cancer had a significantly higher frequency of Arg/Arg (OR = 1.48, 95% CI = 1.01, 2.16) than those with early (stage I/II) gastric cancer among Asians; (iii) patients with poor differentiation had a significantly lower frequency of Pro/Pro (OR = 0.13, 95% CI = 0.03, 0.64) than those with well differentiation among Caucasians. This meta-analysis suggests that the p53 codon 72 polymorphism may be associated with gastric cancer among Asians, and that difference in genotype distribution may be associated with the location, stage, and histological differentiation of gastric cancer. © 2007 Wiley-Liss, Inc.

The ORION statement: guidelines for transparent reporting of outbreak reports and intervention studies of nosocomial infection.

Abstract: The quality of research in hospital epidemiology (infection control) must be improved to be robust enough to influence policy and practice. In order to raise the standards of research and publication, a CONSORT equivalent for these largely quasi-experimental studies has been prepared by the authors of two relevant systematic reviews, following consultation with learned societies, editors of journals and researchers. It consists of a 22 item checklist, and a summary table. The emphasis is on transparency to improve the quality of reporting and on the use of appropriate statistical techniques. The statement has been endorsed by a number of professional special interest groups and societies. Like CONSORT, ORION should be considered a 'work in progress', which requires ongoing dialogue for successful promotion and dissemination. The statement is therefore offered for further public discussion. Journals and research councils are strongly recommended to incorporate it into their submission and reviewing processes. Feedback to the authors is encouraged and the statement will be revised in 2 years.

Reports of clinical trials should begin and end with up-to-date systematic reviews of other relevant evidence: a status report.

Abstract: Objective Scientific and ethical justification for new clinical trials requires them to have been designed in the light of scientifically defensible assessments of relevant previous research. Reliable interpretation of the results of new clinical trials entails setting them in the context of updates of the reviews upon which they were deemed scientifically and ethically justifiable. We have shown previously that most reports of randomized trials published in five general medical journals in May 1997 and in May 2001 failed to set their results in the context of the findings from similar research. In the current study, we assess whether there had been progress in this respect in 2005 and also investigate the extent to which reports begin by referring to systematic reviews providing the justification for the new research reported. Design Assessment of the Introduction and Discussion sections in all reports of randomized trials published during May 2005 in five general medical journals. Setting Reports of randomized trials in five general medical journals. Participants Annals of Internal Medicine, BMJ, JAMA, Lancet and New England Journal of Medicine. Interventions None. Main outcome measures The inclusion or mention of one or more systematic reviews in the Introduction or Discussion section of each report assessed. Results We found 18 reports of randomized trials. The Introduction sections referred to systematic reviews in five (27%) of these reports. None of the Discussion sections of the 15 reports of trials that were not the first published trials to address the question studied placed the results of the new trial in the context of an updated systematic review of other research. Although reference was made to relevant systematic reviews in five of these 15 reports, there was no integration—quantitative or qualitative—of the results of the new trials in an update of these reviews. In the remaining ten reports there was no evidence that any systematic attempt had been made to set the new results in the context of previous trials. Conclusions There is no evidence of progress between 1997 and 2005 in the proportion of reports of trials published in general medical journals which discussed new results within the context of up-to-date systematic reviews of relevant evidence from other controlled trials. Although the proportion of trials referring to systematic reviews in Discussion sections has increased, the majority of reports continued to fail even to do this. Similarly, most researchers appear not to have considered a systematic review when designing their trial. Researchers and journal editors do a disservice to the interests of the public and others involved in healthcare decision-making by acquiescing in this situation.

The nature of evidence resources and knowledge translation for health promotion practitioners

Abstract: Governments and other public health agencies have become increasingly interested in evidence-informed policy and practice. Translating research evidence into programmatic change has proved challenging and the evidence around how to effectively promote and facilitate this process is still relatively limited. This paper presents the findings from an evaluation of a series of evidence-based health promotion resources commissioned by the Victorian Department of Human Services. The evaluation used qualitative methods to explore how practitioners for whom the resources were intended, viewed and used them. Document and literature review and analysis, and a series of key informant interviews and focus groups were conducted. The findings clearly demonstrate that the resources are unlikely to act as agents for change unless they are linked to a knowledge management process that includes practitioner engagement. This paper also considers the potential role of knowledge brokers in helping to identify and translate evidence into practice. Language: en

Rosiglitazone for type 2 diabetes mellitus

Abstract: Background Diabetes has long been recognised as a strong, independent risk factor for cardiovascular disease, a problem which accounts for approximately 70% of all mortality in people with diabetes. Prospective studies show that compared to their non-diabetic counterparts, the relative risk of cardiovascular mortality for men with diabetes is two to three and for women with diabetes is three to four. The two biggest trials in type 2 diabetes, the United Kingdom Prospective Diabetes Study (UKPDS) and the University Group Diabetes Program (UGDP) study did not reveal a reduction of cardiovascular endpoints through improved metabolic control. Theoretical benefits of the peroxisome proliferator activated receptor gamma (PPAR-gamma) activator rosiglitazone on endothelial function and cardiovascular risk factors might result in fewer macrovascular disease events in people with type 2 diabetes mellitus. Objectives To assess the effects of rosiglitazone in the treatment of type 2 diabetes. Search methods Studies were obtained from computerised searches of MEDLINE, EMBASE and The Cochrane Library. Selection criteria Studies were included if they were randomised controlled trials in adult people with type 2 diabetes mellitus and had a trial duration of at least 24 weeks. Data collection and analysis Two authors independently assessed trial quality and extracted data. Pooling of studies by means of fixed-effects meta-analysis could be performed for adverse events only. Main results Eighteen trials which randomised 3888 people to rosiglitazone treatment were identified. Longest duration of therapy was four years with a median of 26 weeks. Published studies of at least 24 weeks rosiglitazone treatment in people with type 2 diabetes mellitus did not provide evidence that patient-oriented outcomes like mortality, morbidity, adverse effects, costs and health-related quality of life are positively influenced by this compound. Metabolic control measured by glycosylated haemoglobin A1c (HbA1c) as a surrogate endpoint did not demonstrate clinically relevant differences to other oral antidiabetic drugs. Occurrence of oedema was significantly raised (OR 2.27, 95% confidence interval (CI) 1.83 to 2.81). The single large RCT (ADOPT - A Diabetes Outcomes Progression Trial) indicated increased cardiovascular risk. New data on raised fracture rates in women reveal extensive action of rosiglitazone in various body tissues. Authors' conclusions New studies should focus on patient-oriented outcomes to clarify the benefit-risk ratio of rosiglitazone therapy. Safety data and adverse events of all investigations (published and unpublished) should be made available to the public.