Cochrane Db Syst Rev
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Cochrane Db Syst Rev · Apr 2007
ReviewGrey literature in meta-analyses of randomized trials of health care interventions.
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. ⋯ 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.
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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. ⋯ Health researchers using postal questionnaires can increase response rates using the strategies shown to be effective in this systematic review.
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Many treatments are available for whiplash patients but there is little scientific evidence for their accepted use. Patients with whiplash-associated disorders (WAD) can be classified by the severity of signs and symptoms from Grade 0 (no complaints or physical signs) to Grade 4 (fracture or dislocation). ⋯ The current literature is of poor methodological quality and is insufficiently homogeneous to allow the pooling of results. Therefore, clearly effective treatments are not supported at this time for the treatment of acute, subacute or chronic symptoms of whiplash-associated disorders.
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The severe and long-lasting symptoms of schizophrenia are often the cause of severe disability. Environmental stress such as life events and the practical problems people face in their daily can worsen the symptoms of schizophrenia. Deficits in problem solving skills in people with schizophrenia affect their independent and interpersonal functioning and impair their quality of life. As a result, therapies such as problem solving therapy have been developed to improve problem solving skills for people with schizophrenia. ⋯ We found insufficient evidence to confirm or refute the benefits of problem solving therapy as an additional treatment for those with schizophrenia. The small number of participants, the quality of reporting of methods and results were of concern. More trials with adequate reporting of methods to minimize bias, adequately powered, with validated, reliable and clinically meaningful outcomes are needed to provide robust evidence to guide policy and practice.
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Cochrane Db Syst Rev · Apr 2007
ReviewIncentives and disincentives to participation by clinicians in randomised controlled trials.
Patients and clinicians need reliable, up-to-date information from randomised controlled trials (RCTs) on the costs and benefits of treatments. Recruitment difficulties arise when clinicians do not invite patients to participate in trials. ⋯ The impact of factors varied across studies. Researchers need to be aware that aspects of the design and conduct of trials can affect clinicians' willingness to invite patients to participate. Further research is needed.