Cumulative meta-analysis of clinical trials builds evidence for exemplary medical care. Randomised controlled trial of a theoretically grounded tailored intervention to diffuse evidence-based public health practice [ISRCTN23257060]. Same information, different decisions: the influence of evidence on the management of hypertension in the elderly. A randomized controlled trial evaluating the impact of knowledge translation and exchange strategies. Systematic reviews of health effects of social interventions: 1. Finding the evidence: how far should you go? Empirical evidence of bias. Dimensions of methodological quality associated with estimates of treatment effects in controlled trials. Empirical evidence for selective reporting of outcomes in randomized trials: comparison of protocols to published articles. An outreach intervention to implement evidence based practice in residential care: a randomized controlled trial [ISRCTN67855475]. Patient education about anticoagulant medication: is narrative evidence or statistical evidence more effective?
Cumulative meta-analysis of clinical trials (a Bayesian interpretation for accumulating evidence) will profoundly affect medical care by summarizing evidence in the assessment of technology innovations. Application of the technique to the randomized control trials (RCTs) of streptokinase treatment of acute myocardial infarction, reduction of peri-operative mortality by antibiotic prophylaxis, and prevention of death from bleeding peptic ulcers has revealed efficacy years before it was suspected by any other means. Arrangement of the trials according to event rate in the controls, effect sizes, quality of the trials or according to covariables of interest has supplied unique information. If carried out prospectively the technique supplies invaluable information regarding indications for another trial, the number of patients necessary to determine the validity of past trends, and the type of patients who might be benefitted. Careful examination in a cumulative manner of the prior trials can reduce the need for future large trials. Previous studies have shown that Norwegian public health physicians do not systematically and explicitly use scientific evidence in their practice. They work in an environment that does not encourage the integration of this information in decision-making. In this study we investigate whether a theoretically grounded tailored intervention to diffuse evidence-based public health practice increases the physicians' use of research information.
                148 self-selected public health physicians were randomised to an intervention group (n = 73) and a control group (n = 75). The intervention group received a multifaceted intervention while the control group received a letter declaring that they had access to library services. Baseline assessments before the intervention and post-testing immediately at the end of a 1.5-year intervention period were conducted. The intervention was theoretically based and consisted of a workshop in evidence-based public health, a newsletter, access to a specially designed information service, to relevant databases, and to an electronic discussion list. The main outcome measure was behaviour as measured by the use of research in different documents.
                The intervention did not demonstrate any evidence of effects on the objective behaviour outcomes. We found, however, a statistical significant difference between the two groups for both knowledge scores: Mean difference of 0.4 (95% CI: 0.2-0.6) in the score for knowledge about EBM-resources and mean difference of 0.2 (95% CI: 0.0-0.3) in the score for conceptual knowledge of importance for critical appraisal. There were no statistical significant differences in attitude-, self-efficacy-, decision-to-adopt- or job-satisfaction scales. There were no significant differences in Cochrane library searching after controlling for baseline values and characteristics.
                Though demonstrating effect on knowledge the study failed to provide support for the hypothesis that a theory-based multifaceted intervention targeted at identified barriers will change professional behaviour. Evidence-based medicine requires general practitioners (GPs) to act upon the results of clinical trials. Clinical trial evidence may be difficult to understand and apply in practice.
                To investigate whether GPs were unduly influenced in managing hypertension in the elderly by the ways in which benefits of trial results were presented, and to establish whether their current treatment of an elderly hypertensive patient was broadly in line with recent clinical trial evidence.
                Seventy-three GPs attending a refresher course were given a written questionnaire containing data from one clinical trial of treatment of hypertension in the elderly presented in four different ways (absolute risk reduction, relative risk reduction, difference in event-free patients, and number of patients who had to be treated in order to prevent one clinical event), as if from four different trials. The effect of each presentation on treatment preferences was assessed using Likert scales. The results were analysed to determine whether the method of presentation of results influenced decision making. A clinical scenario was presented to investigate their current treatment preferences in an elderly hypertensive.
                All GPs returned completed questionnaires. Relative risk reduction was the only presentation which was significantly different from the others, and was the most likely to influence prescribing. In free-text comments, 75% of GPs admitted having problems understanding statistics commonly found in medical journals. More than 90% conformed with recent clinical trial evidence for the management of hypertension.
                GPs were most influenced by relative risk reduction, and were unaware of how the presentation of research results could affect treatment decisions. Most GPs freely admitted to difficulty in comprehending medical statistics. Almost all of the GPs expressed treatment decisions which were broadly in line with clinical evidence. Significant resources and time are invested in the production of research knowledge. The primary objective of this randomized controlled trial was to evaluate the effectiveness of three knowledge translation and exchange strategies in the incorporation of research evidence into public health policies and programs.
                This trial was conducted with a national sample of public health departments in Canada from 2004 to 2006. The three interventions, implemented over one year in 2005, included access to an online registry of research evidence; tailored messaging; and a knowledge broker. The primary outcome assessed the extent to which research evidence was used in a recent program decision, and the secondary outcome measured the change in the sum of evidence-informed healthy body weight promotion policies or programs being delivered at health departments. Mixed-effects models were used to test the hypotheses.
                One hundred and eight of 141 (77%) health departments participated in this study. No significant effect of the intervention was observed for primary outcome (p < 0.45). However, for public health policies and programs (HPPs), a significant effect of the intervention was observed only for tailored, targeted messages (p < 0.01). The treatment effect was moderated by organizational research culture (e.g., value placed on research evidence in decision making).
                The results of this study suggest that under certain conditions tailored, targeted messages are more effective than knowledge brokering and access to an online registry of research evidence. Greater emphasis on the identification of organizational factors is needed in order to implement strategies that best meet the needs of individual organizations.
                The trial registration number and title are as follows: ISRCTN35240937 -- Is a knowledge broker more effective than other strategies in promoting evidence-based physical activity and healthy body weight programming? There is little guidance on how to identify useful evidence about the health effects of social interventions. The aim of this study was to assess the value of different ways of finding this type of information.
                Retrospective analysis of the sources of studies for one systematic review.
                Case study of a systematic review of the effectiveness of interventions in promoting a population shift from using cars towards walking and cycling.
                Only four of the 69 relevant studies were found in a "first-line" health database such as Medline. About half of all relevant studies were found through the specialist Transport database. Nine relevant studies were found through purposive internet searches and seven relevant studies were found by chance. The unique contribution of experts was not to identify additional studies, but to provide more information about those already found in the literature.
                Most of the evidence needed for this review was not found in studies indexed in familiar literature databases. Applying a sensitive search strategy across multiple databases and interfaces is very labour intensive. Retrospective analysis suggests that a more efficient method might have been to search a few key resources, then to ask authors and experts directly for the most robust reports of studies identified. However, internet publications and serendipitous discoveries did make a significant contribution to the total set of relevant evidence. Undertaking a comprehensive search may provide unique evidence and insights that would not be obtained using a more focused search. To determine if inadequate approaches to randomized controlled trial design and execution are associated with evidence of bias in estimating treatment effects.
                An observational study in which we assessed the methodological quality of 250 controlled trials from 33 meta-analyses and then analyzed, using multiple logistic regression models, the associations between those assessments and estimated treatment effects.
                Meta-analyses from the Cochrane Pregnancy and Childbirth Database.
                The associations between estimates of treatment effects and inadequate allocation concealment, exclusions after randomization, and lack of double-blinding.
                Compared with trials in which authors reported adequately concealed treatment allocation, trials in which concealment was either inadequate or unclear (did not report or incompletely reported a concealment approach) yielded larger estimates of treatment effects (P < .001). Odds ratios were exaggerated by 41% for inadequately concealed trials and by 30% for unclearly concealed trials (adjusted for other aspects of quality). Trials in which participants had been excluded after randomization did not yield larger estimates of effects, but that lack of association may be due to incomplete reporting. Trials that were not double-blind also yielded larger estimates of effects (P = .01), with odds ratios being exaggerated by 17%.
                This study provides empirical evidence that inadequate methodological approaches in controlled trials, particularly those representing poor allocation concealment, are associated with bias. Readers of trial reports should be wary of these pitfalls, and investigators must improve their design, execution, and reporting of trials. Selective reporting of outcomes within published studies based on the nature or direction of their results has been widely suspected, but direct evidence of such bias is currently limited to case reports.
                To study empirically the extent and nature of outcome reporting bias in a cohort of randomized trials.
                Cohort study using protocols and published reports of randomized trials approved by the Scientific-Ethical Committees for Copenhagen and Frederiksberg, Denmark, in 1994-1995. The number and characteristics of reported and unreported trial outcomes were recorded from protocols, journal articles, and a survey of trialists. An outcome was considered incompletely reported if insufficient data were presented in the published articles for meta-analysis. Odds ratios relating the completeness of outcome reporting to statistical significance were calculated for each trial and then pooled to provide an overall estimate of bias. Protocols and published articles were also compared to identify discrepancies in primary outcomes.
                Completeness of reporting of efficacy and harm outcomes and of statistically significant vs nonsignificant outcomes; consistency between primary outcomes defined in the most recent protocols and those defined in published articles.
                One hundred two trials with 122 published journal articles and 3736 outcomes were identified. Overall, 50% of efficacy and 65% of harm outcomes per trial were incompletely reported. Statistically significant outcomes had a higher odds of being fully reported compared with nonsignificant outcomes for both efficacy (pooled odds ratio, 2.4; 95% confidence interval [CI], 1.4-4.0) and harm (pooled odds ratio, 4.7; 95% CI, 1.8-12.0) data. In comparing published articles with protocols, 62% of trials had at least 1 primary outcome that was changed, introduced, or omitted. Eighty-six percent of survey responders (42/49) denied the existence of unreported outcomes despite clear evidence to the contrary.
                The reporting of trial outcomes is not only frequently incomplete but also biased and inconsistent with protocols. Published articles, as well as reviews that incorporate them, may therefore be unreliable and overestimate the benefits of an intervention. To ensure transparency, planned trials should be registered and protocols should be made publicly available prior to trial completion. The aim of this project was to assess whether outreach visits would improve the implementation of evidence based clinical practice in the area of falls reduction and stroke prevention in a residential care setting.
                Twenty facilities took part in a randomized controlled trial with a seven month follow-up period. Two outreach visits were delivered by a pharmacist. At the first a summary of the relevant evidence was provided and at the second detailed audit information was provided about fall rates, psychotropic drug prescribing and stroke risk reduction practices (BP monitoring, aspirin and warfarin use) for the facility relevant to the physician. The effect of the interventions was determined via pre- and post-intervention case note audit. Outcomes included change in percentage patients at risk of falling who fell in a three month period prior to follow-up and changes in use of psychotropic medications. Chi-square tests, independent samples t-test, and logistic regression were used in the analysis.
                Data were available from case notes at baseline (n = 897) and seven months follow-up (n = 902), 452 residential care staff were surveyed and 121 physicians were involved with 61 receiving outreach visits. Pre-and post-intervention data were available for 715 participants. There were no differences between the intervention and control groups for the three month fall rate. We were unable to detect statistically significant differences between groups for the psychotropic drug use of the patients before or after the intervention. The exception was significantly greater use of "as required" antipsychotics in the intervention group compared with the control group after the pharmacy intervention (RR = 4.95; 95%CI 1.69-14.50). There was no statistically significant difference between groups for the numbers of patients "at risk of stroke" on aspirin at follow-up.
                While the strategy was well received by the physicians involved, there was no change in prescribing patterns. Patient care in residential settings is complex and involves contributions from the patient's physician, family and residential care staff. The project highlights challenges of delivering evidence based care in a setting in which there is a paucity of well controlled trial evidence but where significant health outcomes can be attained. To determine the relative impact of incorporating narrative evidence, statistical evidence or both into patient education about warfarin, a widely used oral anticoagulant medication.
                600 patients receiving anticoagulant therapy were randomly assigned to view one of three versions of a video depicting a physician-patient encounter where anticoagulation treatment was discussed, or usual care (no video). The videos differed in whether the physician used narrative evidence (patient anecdotes), statistical evidence, or both to highlight key information. 317 patients completed both the baseline and post-test questionnaires. Questions assessed knowledge, beliefs and adherence to medication and laboratory monitoring regimens.
                All three approaches positively effected patients' warfarin-related knowledge, and beliefs in the importance of lab testing; there was also some indication that viewing a video strengthened belief in the benefits of warfarin. There was some indication that narrative evidence had a greater impact than statistical evidence on beliefs about the importance of lab testing and on knowledge. No other evidence of the differential effectiveness of either approach was found. No statistically significant effect was found on intent to adhere, or documented adherence to lab monitoring.
                Videos depicting a physician-patient dialogue about warfarin were effective in educating patients about anticoagulant medication, and had a positive impact on their beliefs. The use of narrative evidence in the form of patient anecdotes may be more effective than statistical evidence for some patient outcomes.
                Patients on oral anticoagulant therapy may benefit from periodic educational efforts reinforcing key medication safety information, even after initial education and ongoing monitoring. Incorporating patient anecdotes into physician-patient dialogues or educational materials may increase the effectiveness of the message.
There is limited applicable evidence. Therefore, no implications for practice can be drawn. Further research is required and several trials are underway, the findings of which are anticipated to contribute to the body of evidence.