PLoS medicine
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Mike English and colleagues argue that as efforts are made towards achieving universal health coverage it is also important to build capacity to develop regionally relevant evidence to improve healthcare.
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Systematic reviews of the effects of healthcare interventions frequently include non-randomized studies. These are subject to confounding and a range of other biases that are seldom considered in detail when synthesizing and interpreting the results. Our aims were to assess the reliability and usability of a new Cochrane risk of bias (RoB) tool for non-randomized studies of interventions and to determine whether restricting analysis to studies with low or moderate RoB made a material difference to the results of the reviews. ⋯ The Cochrane RoB tool highlighted a wide range of risks of bias in studies included in two widely cited reviews and had the potential to change the conclusions of the reviews. Systematic reviews that incorporate non-randomized studies of medical interventions should include a detailed assessment of RoB for each included study.