The term 'complex intervention' is commonly used by health researchers, but what makes an intervention complex remains contested. The intervention Complexity Assessment Tool for Systematic Reviewers (iCAT_SR) provides systematic review authors with a structure for locating interventions on a continuum according to a number of dimensions of complexity. The iCAT-SR tool may assist in anticipating and planning for implementation challenges, and designing evaluations that are proportionate to the uncertainties posed by an intervention and that focus upon core elements of complexity.
Cochrane Review authors should avoid overemphasis on whether or not a meta-analysis result is statistically significant. The clinical significance and positive or negative implication of an effect estimate should only be emphasised if the statistical assessment is conclusive beyond reasonable doubt.
The conclusions of the recent update of the Cochrane Review of pulmonary rehabilitation in chronic obstructive pulmonary disease (COPD) agree with prior versions, supporting the benefit of pulmonary rehabilitation for improving quality of life. Additional randomised controlled trials are no longer warranted. Cochrane Airways made the unusual decision that this review is now closed and won't be updated.
The value of systematic reviews of small trials has recently been questioned. This editorial illustrates why Cochrane Reviews of small trials are of value and how they can act as important grounds and platforms for trials that are large and robust enough to inform practice. We look at recently updated Cochrane Reviews on the treatment of a common fracture and a common impairment after stroke.
Cochrane Reviews can provide valuable evidence to support an accountable decision-making process to improve Indigenous people’s health. Such a process needs to consider community values, preferences, local needs, and resource use, as well as provide opportunities for feedback and debate.
If systematic reviews are to provide the information that people need when making decisions about health and social care, we need to be confident that the methods used to plan, conduct, and report these reviews result in valid, reliable evidence. The 2015 Cochrane Methods Symposium will focus on why the methods used to produce reviews for evidence-based care should themselves be evidence-based.
The perfect systematic review is an unachievable ideal. The biggest threat to a systematic review's validity is its foundation. If the included trials are not a fair representation of all trials that exist, the results will be biased. The problem of missing relevant data is far from solved. Unfortunately, publically available regulatory data are rarely used in Cochrane Reviews, even though this might be the least time-consuming source of unpublished data from drug trials.
Case management, also known as care management, has been proposed as an intervention to support people with dementia and their carers, but guidelines are cautious about the evidence, judged as at least partially inconclusive. Complex interventions such as case management pose particular challenges to systematic reviewers. A new Cochrane Review of case management offers a valuable information source for practitioners and researchers on rigorously studied case management interventions, although the findings remain mostly inconclusive. Before planning further studies, the next step should be a more thorough analysis of the available evidence to seek conclusions about components that seem to be most successful for relevant outcomes.
Healthy kidneys produce the hormone erythropoietin, which stimulates production of red blood cells in the bone marrow. Anaemia is a common problem for people with advanced chronic kidney disease, due to reduced endogenous erythropoietin production. A new Cochrane Review examines the evidence for erythropoiesis-stimulating agents for anaemia in adults with chronic kidney disease. This review employs the Bayesian statistical approach of network meta-analysis, which allows for both direct and indirect comparisons of different treatments for the same or similar conditions, even when most trials tested a treatment against placebo and did not compare treatment interventions directly.
Authors of Cochrane Reviews are also sometimes authors of trials eligible for inclusion in the Cochrane Review. This dual authorship is clearly a competing interest. This editorial unpacks the dilemma of dual authorship, examines the extent of the problem with existing reviews, and comments on the current Cochrane editorial policy on dual authorship and its implementation.
Preclinical evidence, like clinical evidence, is used to inform decisions about the safety and efficacy of treatments for participants in clinical trials. Unlike clinical studies, most preclinical animal studies are not systematically reviewed. Systematic reviews of preclinical animal studies can however contribute significantly to creating more transparency regarding the possible translation from preclinical animal studies to clinical trials. A small but growing international community of researchers is conducting systematic reviews of preclinical animal studies.
Many couples experiencing infertility will seek treatment in the form of in vitro fertilisation (IVF) or another type of assisted reproductive technology (ART). These treatments are complex and costly, and the stakes are high, so each step should be supported by good evidence from well-designed studies. A recent overview of Cochrane Reviews on ART summarises the evidence from 54 Cochrane Reviews on ART procedures and treatment options. As the number of published systematic reviews increases, overviews are increasingly important to facilitate decision-making for patients and doctors, as well as for guideline panels, policy-makers, and caregivers. The ART overview is by far the largest overview to date and can be used to guide clinical practice, helping to improve live birth rates and reduce adverse events such as multiple pregnancy, cycle cancellation, and ovarian hyperstimulation syndrome.
The Cochrane Collaboration's risk of bias tool has been used in hundreds of systematic reviews over the last five years. There is debate about whether to include funding source as a standard item in the tool. In this editorial, Jonathan Sterne presents the arguments against including funding source in the Cochrane risk of bias tool.
The Cochrane Collaboration's risk of bias tool has been used in hundreds of systematic reviews over the last five years. There is debate about whether to include funding source as a standard item in the tool. In this editorial, Lisa Bero puts the case for including funding source in the Cochrane risk of bias tool.
Systematic reviews addressing a wide range of healthcare questions, and drawing on a range of different study designs, are increasingly available in the literature. The Cochrane Database of Systematic Reviews currently considers Cochrane Reviews on the effectiveness of health interventions and the accuracy of screening and diagnostic tests, as well as overviews of reviews and methodology reviews. November 2013 marks an important milestone for The Cochrane Collaboration with the publication of a review of qualitative studies. This synthesis of qualitative evidence addresses barriers and facilitators to the implementation of lay health worker (LHW) programmes.
Archie Cochrane's seminal work was titled "Effectiveness and efficiency: random reflections on health services", reflecting his belief that healthcare interventions should not only do more good than harm, but should also represent a good use of resources. Since its inception, The Cochrane Collaboration has produced over 5000 systematic reviews of the effectiveness of interventions, but these have largely ignored the challenge to provide information on efficiency. Is this a problem and, if so, what can be done about it?
A Cochrane Review was recently stated to have "uncritically included" data under suspicion. We write to correct some misunderstandings about the writing and editing of this review, and we also challenge The Cochrane Collaboration to authorise a working group to develop and implement a methodology that estimates data integrity and standards for the inclusion or non-inclusion of studies under suspicion but not yet retracted.
Randomised clinical trials are often inadequately reported and may be inadequately conducted. Any associated biases could impact seriously on the findings and conclusion of a systematic review. Authors of systematic reviews thus need to assess the risk of bias in included randomised clinical trials. In this 20th Anniversary editorial, we look at the evolution of guidance on appraising studies included in Cochrane Reviews.
Lipitor (atorvastatin) is one of the best-selling pharmaceutical drugs of all time. This month's issue of the Cochrane Database of Systematic Reviews includes a new review by Wright, Adams, and Tsang concerning the effects of this statin. The review is big, and it is not like most of the others in the database.
When people making decisions about health care look for guidance from research, the outcomes reported by that research are key; however, there is a general lack of consensus regarding the choice of outcomes in particular clinical settings, which affects trial design, conduct, analysis, and reporting.
Systematic reviews seek to identify and summarise all the relevant research evidence relating to the clinical or health policy decision under consideration. This rationale can be fatally undermined if the review only includes a proportion of the research conducted, due to the restricted availability of some studies or their data. The recognition of reporting bias and its potential to confound the results of evidence synthesis is not new, and there is now ample methodological research demonstrating that studies with 'positive' results are more likely to be published and published sooner, than those with 'negative' results. If systematic reviews fail to address reporting biases they are at risk of generating misleading results. We should, therefore, pay particular attention to reviews that either identify strong evidence of a risk of reporting bias or adopt innovative methods to overcome it.
Cochrane Reviews are essential tools for accurately summarising the evidence of the effects of healthcare interventions in a way that minimises bias. In addition to occasionally providing clear clinical answers, when several smaller apparently conflicting studies are brought together, such reviews are a rich resource for people planning to fund or undertake future healthcare research.
A variety of international organisations, funders, and others have made calls for sharing research data. These calls have mostly been restricted to publicly funded research, but if the over-riding objective of healthcare research is to improve patient care and health policy, the distinction between publicly funded research and industry-funded research is artificial and irrelevant. It is pretty clear that if commercial concerns lead to the withholding of data that are important for rational decision-making by doctors and patients, there is something fundamentally wrong.
To listen to a podcast of this editorial, please click here.
We find it fascinating that both Cyna et al. and ourselves begin at the exact same point – that is, patient protection is paramount – yet we end up at diametrically opposing views regarding the use of invasive ‘placebos’ in randomised controlled trials (RCTs).
Placebo controls are frequently used to ‘blind’ participants, trial personnel and outcome assessors to intervention and control in clinical trials. Effective blinding of treatment reduces the risk of performance bias (differences between groups in the care provided apart from the intervention being evaluated) and detection bias (differences between groups in how outcomes are ascertained, diagnosed or verified). A placebo has traditionally been defined as an “inert or innocuous substance”, such as a ‘sugar pill’.