module 4 finding the evidence: individual trials

Module 4Module 4Finding the Evidence:Finding the Evidence:Individual TrialsIndividual Trials

Meta analysesSystematic reviews

Randomized control trials (RCTs)Controlled trials w/o randomization

Cohort studiesCase control studies/retrospective cohortCase studies/qualitative studies

EBM Literature: Reviews

Individual Studies:Experimental

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Individual Studies:Observational

Evidence hierarchy

Resources for Trials

Resources for Trials

CENTRAL

Resources for Trials

TRIP Database

TRIP Database

Resources for Trials

1. RecruitmentWho did the subjects represent?

2. Allocation Was the assignment to treatments randomized? Were the groups similar at the trial’s start?

3. MaintenanceWere the groups treated equally?Were outcomes ascertained & analyzed for most patients?

4. MeasurementsWere patients and clinicians “blinded” to treatment? ORWere measurements objective & standardized?

Appraisal - RAMMbo

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

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

Be careful

Module 4Module 4Finding the Evidence:Finding the Evidence:Individual TrialsIndividual Trials