Systematic reviews and meta-analysis in aging research

Abstract

Systematic reviews and meta-analyses are proven tools for decision-making in health care, both for patients and public policy. For example, nowadays they constitute a substantial part of evidence-based clinical practice guidelines. However, the number of systematic reviews developed so far, and their use to improve the health of older adults has been somehow slow. This chapter describes in detail each of the steps necessary to conceptualize and conduct systematic reviews and meta-analysis. It begins with a description of the different uses these types of tools have, followed by the differences they have with narrative reviews. Regarding the methodology to assemble them, it starts in the form of how the research question is formulated, which is the essence for the construction of each of systematic reviews. Then we continue with the selection of studies, first by searching in different electronic databases (e.g., Medline, Embase). Once studies are located, each of them should be reviewed thoroughly to determine if they comply strictly with the selection criteria. Finally, with the selected studies the next step is data extraction from each one, which eventually constitutes the results section of the systematic review. In addition, it is necessary to assess the methodological quality of each study to determine if they are free of bias. The last part of the chapter focuses on the different alternatives of meta-analyses, including network meta-analysis. The results are reported qualitatively when they are systematic reviews, while meta-analyses are reported quantitatively, as long as two or more studies can be combined.