What is Wrong With Systematic Reviews and Meta-Analyses: If You Want the Right Answer, Ask the Right Question!

Abstract

We see more and more systematic reviews (qualitative pooling) and their variant meta-analyses (quantitative pooling) being published in the Aesthetic Surgery Journal . Systematic reviews and meta-analyses are on the top of the hierarchy of evidence; hence their impact in practice can be quite large if done correctly.1 Unfortunately the current quality of published systematic reviews in plastic surgery is poor.2 The statistical jargon that is presented in most systematic reviews and meta-analyses seems impressive for the naive reader who may unwittingly accept their conclusions. In this edition of the Hub we will use the published meta-analysis by Carloni et al, “Are There Factors Predictive of Postoperative Complications in Circumferential Contouring of the Lower Trunk? A Meta-Analysis”3 as a springboard to highlight some basic concepts of systematic review and meta-analysis. We also explain some of the common pitfalls and offer guidance how to improve your next systematic review or meta-analysis (or critical appraisal thereof!). ### What is the Difference Between a Regular Review and a Systematic Review? The main difference in a systematic review from a regular review is the great effort that investigators make and steps they take to avoid the introduction of bias in answering their clinical question when performing a systematic review. The same applies on the reporting of their findings. There are various steps in which bias can be introduced in the review. Table 1 below shows the key differences between a regular review and a systematic review.4 When a systematic review provides a quantitative summary and a statistical synthesis, we label this as a meta-analysis.4 View this table: Table 1. Differences Between Narrative Reviews and Systematic Reviews ### Why Perform a Systematic Review or its Variant Meta-Analysis? While a systematic review is a structured approach to collect and synthesize data qualitatively to answer an important clinical question, a meta-analysis takes this pooling of information one step further; it pools and analyzes the data quantitatively. Like a systematic review, …