Systematic Review of Surgical Treatments for Fecal Incontinence :

Including only a portion of all available evidence may introduce systematic errors into the meta-analytic process and threaten its validity. We set out to examine whether language restricted meta-analyses, compared to language inclusive meta-analyses, provide different estimates of the effectiveness of interventions evaluated in randomized trials. We identified and retrieved all 79 meta-analyses from several disease areas in which explicit eligibility criteria regarding trial selection were reported. General characteristics and quality of reporting of the meta-analyses were assessed using a validated instrument. We explored the effects of language of publication of the randomized trials on the quantitative results using logistic regression analyses. Language restricted meta-analyses, compared to language inclusive meta-analyses, did not differ with respect to the estimate of benefit of the effectiveness of an intervention (ROR = 0.98; 95% CI: 0.81-1.17). These results were also robust after a series of sensitivity analyses. This study provides no evidence that language restricted meta-analyses lead to biased estimates of intervention effectiveness. We encourage others to replicate this study using different sampling frames, clinical topics and interventions.

To create a practical and validated item bank for evaluating the risk of bias and precision of observational studies of interventions or exposures included in systematic evidence reviews. The item bank, developed at RTI International, was created based on 1,492 questions included in earlier instruments, organized by the quality domains identified by Deeks et al. Items were eliminated and refined through face validity, cognitive, content validity, and interrater reliability testing. The resulting item bank consisting of 29 questions for evaluating the risk of bias and precision of observational studies of interventions or exposures (1) captures all of the domains critical for evaluating this type of research, (2) is comprehensive and can be easily lifted "off the shelf" by different researchers, (3) can be adapted to different topic areas and study types (e.g., cohort, case-control, cross-sectional, and case series studies), and (4) provides sufficient instruction to apply the tool to varied topics. One bank of items, with specific instructions for focusing abstractor evaluations, can be created to judge the risk of bias and precision of the variety of observational studies that may be used in systematic and comparative effectiveness reviews. Copyright © 2012 Elsevier Inc. All rights reserved.