Discrepancies among megatrials

Systematic reviews on selected nutrition interventions: descriptive assessment of conduct and methodological challenges

“…In addition, conflict and fragility also occur at the sub-national level within some strongly performing countries. Systematic reviews and meta-analysis have become increasingly popular in evidence-based healthcare over the past two decades [16], although these have been evaluated for reliability since quite a long time [17][18][19][20]. Rigorous and transparent systematic reviews are recognized internationally as a credible source for evidence of effects and as the basis for evidence-informed policy and decisions [16,21,22].…”

Procedures and methods of benefit assessments for medicines in Germany

“…A systematic comparison of these three empirical assessments concluded that the disagreements may be less prominent for primary outcomes and that overall the frequency of significant disagreements beyond chance is 10-25% [41,42]. Disagreement may also exist among trials [43] and among meta-analyses [44]. These discrepancies suggest that a dogmatic approach with respect to a minimum number of studies needed is difficult to support.…”

Synthesizing medical evidence: systematic reviews and metaanalyses

“…The lack of a true gold standard makes this type of inquiry difficult: agreement between large RCTs is no better than agreement between metaanalyses. 124 Finally, it is important to remember that although a metaanalysis may be the most rigorous method available to measure treatment effect, other factors should also enter into making a treatment recommendation. Because many effective treatments can cause harm to some individuals, it is important to consider patient values and preferences in weighing risks against benefits.…”