Critical appraisal of systematic reviews and meta-analyses: a step-by-step guide for nephrologists

Background Systematic reviews and meta-analyses play a pivotal role in evidence-based medicine, including nephrology, by consolidating findings from multiple studies. To maximize their utility, rigorous quality assessment during peer review is essential. Challenges such as heterogeneity, bias, and methodological flaws often undermine these studies, necessitating a structured appraisal process. Methods This guide outlines a framework for nephrologists on appraising systematic reviews and meta-analyses. Key areas include heterogeneity assessment using the I2 statistic, interpretation of forest plots for pooled effect estimates, and the use of funnel plots with Egger's test to identify potential publication bias. Risk of bias is evaluated using RoB 2 for randomized controlled trials and ROBINS-I for non-randomized studies. Subgroup and sensitivity analyses, along with meta-regression, address heterogeneity and examine the robustness of findings. Results The I2 statistic quantifies heterogeneity by estimating the proportion of variability in a meta-analysis. Funnel plots and Egger's test help detect publication bias. Major biases, such as selection, performance, detection, and publication bias, are identified using structured tools like AMSTAR 2, Cochrane RoB 2, and ROBINS-I. The GRADE framework further assesses the overall certainty of the evidence. Emphasis is placed on PRISMA compliance, protocol pre-registration, and transparent reporting of statistical analyses, subgroup, and sensitivity assessments. The inclusion of grey literature remains optional. Conclusion By focusing on key areas such as heterogeneity, risk of bias, and robust statistical methods, this guide enables nephrologists to critically appraise systematic reviews and meta-analyses, fostering better clinical decision-making and improved patient care in nephrology.