[From Opinion to Structure: The Role of Different Types of Systematic Reviews Within the Evidence Synthesis...

In the current context of increasing production of biomedical studies, health professionals face significant challenges in remaining updated with the latest knowledge. Given this reality, literature reviews have emerged as vital tools to synthesize and organize existing knowledge in a coherent and accessible manner. Traditionally, narrative reviews have provided an initial approach to specific topics; however, these studies exhibit significant methodological limitations as they do not systematically describe the processes of identification, selection, and analysis of information. In contrast, systematic reviews adhere to explicit and rigorous methods that enable specific clinical questions to be answered with greater validity and reproducibility, thereby establishing a higher standard of evidence synthesis. The evidence synthesis ecosystem has experienced remarkable expansion in recent years, diversifying into multiple types of systematic reviews, each designed to address various research questions. The key to selecting the most suitable review lies in clearly defining the research question and the specific objective being pursued. The current trend indicates a shift from opinion studies -such as narrative reviews, which are primarily helpful for teaching clinicians and early career researchers- to systematically structured designs that address specific clinical questions and serve primarily for informed decision-making and the identification of research gaps. This article aims to provide key guidelines for selecting the most appropriate type of review according to the research question posed, as well as to describe the essential methodological aspects that should be considered during its development and reporting.