IMG_9121.JPG

# Chapter 10: Systematic Revision ## Systematic Reviews A systematic review (SR) of the evidence is a structured, rigorous, comprehensive, and multidisciplinary methodology applied to the search, evaluation, and synthesis of the best available evidence to answer a specific clinical question. An...

# Chapter 10: Systematic Revision ## Systematic Reviews A systematic review (SR) of the evidence is a structured, rigorous, comprehensive, and multidisciplinary methodology applied to the search, evaluation, and synthesis of the best available evidence to answer a specific clinical question. An SR uses the same procedure as any other research study: an objective is formulated, evidence is sought, identified, and assessed following a protocol with explicit criteria, and conclusions are drawn from the analysis of the collected data and the interpretation of the results. Although the terms "systematic review" and "meta-analysis" are often used interchangeably, meta-analysis refers to the statistical procedure used to integrate the results of different studies and obtain a combined estimate, while the concept of SR applies to the entire research process described above. ## Phases of a Systematic Revision An SR is a research study that, unlike those presented in earlier chapters, is not conducted on primary data. That is, it does not collect information directly from subjects, but rather compiles data previously collected in other studies. SRs can be considered observational studies where the "study population" is made up of the best original articles on the subject of the revision. Like any other study, an SR requires the development of a protocol specifying the definitions and procedures that will be carried out in its various stages (Table 10.1). ## Definition of the Objective The purpose of an SR is to attempt to answer a specific clinical question by evaluating all available evidence from previous research. The first step, therefore, is to clearly and precisely define the research question, explicitly stating the study factor (intervention, exposure, or diagnostic procedure being evaluated), the comparison or reference, the outcome variable (specifying the measure of the effect being used, such as the reduction of incidence or mortality, improvement of symptoms, etc.), and the study population (specifying the type of patient and the clinical condition). It is also advisable to identify the type of study to be included. In general, the more precise the definition of the question to be answered, the better the SR.