Can Umbrella Reviews Establish Consensus in Clinical Practice?

Abstract

Evidence-based clinical practice is grounded in research and interpretation of findings. Individual studies capture only part of the evidence relevant to a clinical question, making synthesis important for evaluating consistency and precision. Systematic reviews bring relevant studies together, and meta-analyses use statistical methods to integrate findings. Umbrella reviews emerged to organise and contextualise findings across multiple reviews on a given topic. Convergence across umbrella reviews can support decision-making, but apparent agreement does not necessarily represent independent confirmation when the same primary studies recur across reviews. Substantial overlap can also create apparent disagreement when similar evidence is analysed using different eligibility criteria, outcome selection, or statistical methods. Dependence among included syntheses can persist despite established methods for identifying and managing overlap. The number of concordant syntheses should not be mistaken for the number of independent lines of evidence.