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Module 4 Finding the Evidence: Individual Trials. EBM Literature: Reviews. Individual Studies: Experimental. Individual Studies: Observational. Evidence hierarchy. Search ordr. Level of evidence. Meta analyses Systematic reviews Randomized control trials (RCTs)
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EBM Literature: Reviews Individual Studies:Experimental Individual Studies:Observational Evidence hierarchy Search ordr Level of evidence Meta analyses Systematic reviews Randomized control trials (RCTs) Controlled trials w/o randomization Cohort studies Case control studies/retrospective cohort Case studies/qualitative studies
RecruitmentWho did the subjects represent? Allocation Was the assignment to treatments randomized? Were the groups similar at the trial’s start? MaintenanceWere the groups treated equally?Were outcomes ascertained & analyzed for most patients? MeasurementsWere patients and clinicians “blinded” to treatment? ORWere measurements objective & standardized? Appraisal - RAMMbo
Be careful • 102 trial protocols (3736 outcomes) 122 published journal articles • 62% of trials discrepancy in outcomes • 92% of trials incomplete reporting of efficacy outcomes • 86% of authors denied existence of unreported outcomes despite evidence • Statistically significant outcomes had a higher odds of being fully reported Chan JW, et al. 2004. Empirical evidence for selective reporting of outcomes in randomized trials: comparison of protocols to published articles. JAMA 291(20):2457