The GRADE approach, Part 1: how to assess the certainty of the evidence

Abstract

The certainty of the evidence for interventions is the certainty or confidence that the true effect is within a particular range or relative to a threshold. In the new pyramid of evidence, systematic reviews represent the magnifying glass through which this certainty is evaluated. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach arises in response to the existence of multiple evidence classification systems, and it offers a transparent and structured process to develop and present summaries of evidence considering its certainty and, in a second step, the strength of the recommendations that they inform. The GRADE process begins with an explicit question that includes all important and critical outcomes explicitly. The main domains used to assess the certainty of the evidence are risk of bias, inconsistency, indirectness of evidence, imprecision, and publication bias. The factors that can increase the certainty of the evidence are dose-response gradient, large magnitude of an effect, and effect of plausible residual confounding. Finally, the Summary of Findings tables summarize the process in a simplified way and with controlled language. This narrative review’s purpose is to address the GRADE approach’s theoretical and practical underlying concepts in a simplified way and with practical examples.

High versus Standard Intensity of Thromboprophylaxis in Hospitalized Patients with COVID-19: A Systematic Review and Meta-Analysis

“…using the GRADE approach (grading of recommendations assessment, development and evaluation) described in Chapter 14 of The Cochrane Handbook for Systematic Reviews of Interventions [ 16 ]. The certainty of evidence was deemed as high, moderate, low, or very low, depending on factors that either decrease the confidence of the outcome—such as the risk of bias, the publication bias, the inconsistency, the indirectness, and the imprecision of results—or factors that increase the certainty—such as the large effect size, the dose response, and the effect of plausible residual confounding [ 17 ].…”

Metabolic risk factors for non-communicable diseases in Ethiopia: a systematic review and meta-analysis

“…Heterogeneity across studies was assessed using the I² index, values greater than 75% indicated substantial heterogeneity. 20 The Z-statistic was used for testing associations with α≤0.05 as cut-off to determine statistical significance level. Then we identified studies that reported statistically significant associations between sex or age of participants and metabolic risk factors to extract ORs, CIs and p values.…”

Hand hygiene and hand eczema: A systematic review and meta‐analysis

“…Evidence from observational studies started at the low quality level, and was subsequently assessed across various domains including risk of bias, imprecision, inconsistency, indirectness and publication bias for downgrading or upgrading. 16 , 17 Any discrepancy in rating was resolved by consensus.…”