Effects on patients of their healthcare practitioner's or institution's participation in clinical trials: A systematic review

Background: Systematic reviews have shown uncertainty about the size or direction of any 'trial effect' for patients in trials compared to those treated outside trials. We are not aware of any systematic review of whether there is a 'trial effect' related to being treated by healthcare practitioners or institutions that take part in research.  Methods: We searched the Cochrane Methodology Register and MEDLINE (most recently in January 2009) for studies in which patients were allocated to treatment in one or other setting, and cohort studies reporting the outcomes of patients from different settings. We independently assessed study quality, including the control of bias in the generation of the comparison groups, and extracted data.  Results: We retrieved and checked more than 15,000 records. Thirteen articles were eligible: five practitioner studies and eight institution studies. Meta-analyses were not possible because of heterogeneity. Two practitioner studies were judged to be 'controlled' or better. A Canadian study among nurses found that use of research evidence was higher for those who took part in research working groups and a Danish study on general practitioners found that trial doctors were more likely to prescribe in accordance with research evidence and guidelines. Five institution studies were 'controlled' but provided mixed results. A study of North American patients at hospitals that had taken part in trials for myocardial infarction found no statistically significant difference in treatment for patients in trial and non-trial hospitals. A Canadian study of myocardial infarction patients found that trial participants had better survival than patients in the same hospitals who were not in trials or those in non-trial hospitals. A study of general practices in Denmark did not detect differences in guideline adherence between trial and non-trial practices but found that trial practices were more likely to prescribe the trial sponsor's drugs. The other two 'controlled' studies of institutions found lower mortality in trial than non-trial hospitals.  Conclusions: The available findings from existing research suggest that there might be a 'trial effect' of better outcomes, greater adherence to guidelines and more use of evidence by practitioners and institutions that take part in trials. However, the consequences for patient health are uncertain and the most robust conclusion may be that there is no apparent evidence that patients treated by practitioners or in institutions that take part in trials do worse than those treated elsewhere

Evaluating interventions for informed consent for surgery (ICONS) :Protocol for the development of a core outcome set

Abstract Background The concept of informed consent is fundamental to medical practice. Shortcomings in the process can lead to patient complaints, litigation, unmet expectations and poor outcomes. Consent research has focused on developing tools to improve patient recall and understanding. However, the definitions, methods of measurement and timing of measurement vary widely across the studies that have been done. Although a Cochrane review has reported that many of these interventions appear to work, the high level of heterogeneity in outcome reporting prevents the identification of those interventions that work best and why they do so. It is also not clear which outcomes are most important to each party involved in the consent process and why. Methods/design This project will develop a core outcome set for assessing the effects of interventions aimed at improving informed consent for surgery and other invasive procedures for adult patients with the capacity to consent for themselves. We will conduct a systematic review of the qualitative and quantitative literature to identify outcomes used to date in consent research and map these into domains. A series of semi-structured key stakeholder interviews will also be used to identify relevant outcomes. These processes will produce a list of potential outcomes for assessing the effects of interventions to improve consent, which will be refined through an international Delphi survey and consensus webinars involving key stakeholders to produce the core outcome set. Discussion The ICONS study aims to develop a core outcome set for use in trials and reviews of interventions designed to improve the informed consent process for surgery and other invasive procedures. Our aim is that this core outcome set will reduce the level of selection and reporting bias in consent research and help clinicians to compare tools to improve consent

Human search for a target on a textured background is consistent with a stochastic model

Previous work has demonstrated that search for a target in noise is consistent with the predictions of the optimal search strategy, both in the spatial distribution of fixation locations and in the number of fixations observers require to find the target. In this study we describe a challenging visual-search task and compare the number of fixations required by human observers to find the target to predictions made by a stochastic search model. This model relies on a target-visibility map based on human performance in a separate detection task. If the model does not detect the target, then it selects the next saccade by randomly sampling from the distribution of saccades that human observers made. We find that a memoryless stochastic model matches human performance in this task. Furthermore, we find that the similarity in the distribution of fixation locations between human observers and the ideal observer does not replicate: Rather than making the signature doughnut-shaped distribution predicted by the ideal search strategy, the fixations made by observers are best described by a central bias. We conclude that, when searching for a target in noise, humans use an essentially random strategy, which achieves near optimal behavior due to biases in the distributions of saccades we have a tendency to make. The findings reconcile the existence of highly efficient human search performance with recent studies demonstrating clear failures of optimality in single and multiple saccade tasks

Compression stockings for preventing deep vein thrombosis (DVT) in airline passengers

Background Air travel might increase the risk of deep vein thrombosis (DVT). It has been suggested that wearing compression stockings might reduce this risk. This is an update of the review first published in 2006. Objectives To assess the effects of wearing compression stockings versus not wearing them for preventing DVT in people travelling on flights lasting at least four hours. Search methods The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 1 April 2020. We also checked the bibliographies of relevant studies and reviews identified by the search to check for any additional trials. Selection criteria Randomised trials of compression stockings versus no stockings in passengers on flights lasting at least four hours. Trials in which passengers wore a stocking on one leg but not the other, or those comparing stockings and another intervention were also eligible. Data collection and analysis Two review authors independently selected trials for inclusion and extracted data. We sought additional information from trialists where necessary. Main results One new study that fulfilled the inclusion criteria was identified for this update. Twelve randomised trials (n = 2918) were included in this review: ten (n = 2833) compared wearing graduated compression stockings on both legs versus not wearing them; one trial (n = 50) compared wearing graduated compression tights versus not wearing them; and one trial (n = 35) compared wearing a graduated compression stocking on one leg for the outbound flight and on the other leg on the return flight. Eight trials included people judged to be at low or medium risk of developing DVT (n = 1598) and two included high‐risk participants (n = 1273). All flights had a duration of more than five hours. Fifty of 2637 participants with follow‐up data available in the trials of wearing compression stockings on both legs had a symptomless DVT; three wore stockings, 47 did not (odds ratio (OR) 0.10, 95% confidence interval (CI) 0.04 to 0.25, P Authors' conclusions There is high‐certainty evidence that airline passengers similar to those in this review can expect a substantial reduction in the incidence of symptomless DVT and low‐certainty evidence that leg oedema is reduced if they wear compression stockings. The certainty of the evidence was limited by the way that oedema was measured. There is moderate‐certainty evidence that superficial vein thrombosis may be reduced if passengers wear compression stockings. We cannot assess the effect of wearing stockings on death, pulmonary embolism or symptomatic DVT because no such events occurred in these trials. Randomised trials to assess these outcomes would need to include a very large number of people

Outcome measures in rheumatoid arthritis randomised trials over the last 50 years

BACKGROUND: The development and application of standardised sets of outcomes to be measured and reported in clinical trials have the potential to increase the efficiency and value of research. One of the most notable of the current outcome sets began nearly 20 years ago: the World Health Organization and International League of Associations for Rheumatology core set of outcomes for rheumatoid arthritis clinical trials, originating from the OMERACT (Outcome Measures in Rheumatology) Initiative. This study assesses the use of this core outcome set by randomised trials in rheumatology. METHODS: An observational review was carried out of 350 randomised trials for the treatment of rheumatoid arthritis identified through The Cochrane Library (up to and including September 2012 issue). Reports of these trials were evaluated to determine whether or not there were trends in the proportion of trials reporting on the full set of core outcomes over time. Researchers who conducted trials after the publication of the core set were contacted to assess their awareness of it and to collect reasons for non-inclusion of the full core set of outcomes in the study. RESULTS: Since the introduction of the core set of outcomes for rheumatoid arthritis, the consistency of measurement of the core set of outcomes has improved, although variation in the choice of measurement instrument remains. The majority of trialists who responded said that they would consider using the core outcome set in the design of a new trial. CONCLUSIONS: This observational review suggests that a higher percentage of trialists conducting trials in rheumatoid arthritis are now measuring the rheumatoid arthritis core outcome set. Core outcome sets have the potential to improve the evidence base for health care, but consideration must be given to the methods for disseminating their availability amongst the relevant communities

A research methodology study to map the process of initiating and operating a randomised controlled trial of podoconiosis treatment in Northern Ethiopia

No description supplie

Publication bias in clinical trials

This is the protocol for a review and there is no abstract. The objectives are as follows: To summarise evidence of publication bias for trials of health care interventions.Output Type: Protoco

A homogeneous aa index: 1. secular variation

Originally complied for 1868-1967 and subsequently continued so that it now covers 150 years, the aa index has become a vital resource for studying space climate change. However, there have been debates about the inter-calibration of data from the different stations. In addition, the effects of secular change in the geomagnetic field have not previously been allowed for. As a result, the components of the “classical” aa index for the southern and northern hemispheres (aaS and aaN) have drifted apart. We here separately correct both aaS and aaN for both these effects using the same method as used to generate the classic aa values but allowing {\delta}, the minimum angular separation of each station from a nominal auroral oval, to vary as calculated using the IGRF-12 and gufm1 models of the intrinsic geomagnetic field. Our approach is to correct the quantized aK-values for each station, originally scaled on the assumption that {\delta} values are constant, with time-dependent scale factors that allow for the drift in {\delta}. This requires revisiting the intercalibration of successive stations used in making the aaS and aaN composites. These intercalibrations are defined using independent data and daily averages from 11 years before and after each station change and it is shown that they depend on the time of year. This procedure produces new homogenized hemispheric aa indices, aaHS and aaHN, which show centennial-scale changes that are in very close agreement. Calibration problems with the classic aa index are shown to have arisen from drifts in {\delta} combined with simpler corrections which gave an incorrect temporal variation and underestimate the rise in aa during the 20th century by about 15%