A systematic review is a process to answer a research question by collecting and summarizing all pragmatic evidence that fits pre-specified eligibility criteria while a meta-analysis is the use of statistical methods to summarize the results of these studies (a large collection of results from individual studies). Systematic reviews are just like other research articles, can be of varying quality. It is not necessary that all systematic reviews would have a meta-analysis and not all review articles are systematic reviews.
Information about healthcare is everywhere. However, it is difficult to know if one healthcare intervention works better than another or if it will do more harm than good? That’s why it is important to keep track of evidence and information, using systematic reviews. It is necessary to plan a review carefully, document everything and approach rigorously with careful attention to detail. Figure 1 briefly describes the process of conducting a systematic review.
Cochrane Library is the main product of the Cochrane collaboration and, is the single best place to find independent, high quality evidence for health care decision making. However, there are few more sources available presented in Figure 2 where you may register and find studies according to your objective.
Cochrane Handbook for Systematic Reviews of Interventions is available at http://handbook-5-1.cochrane.org/. Equator network: a library for health research reporting provides reporting guidelines for systematic review i.e Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). It provides exactly what the author state in the paper. PRISMA provides guidance on what investigator should include when reporting a systematic review.
PRISMA checklist and PRISMA flow diagram is attached with this blog and also available in their website.
A meta-analysis is a quantitative approach used to systematically assess previous research studies to derive conclusions about the research and epidemiological studies. Outcomes of a meta-analysis include a more precise estimate of the effect of treatment or risk factor for disease, than any individual study causative to the pooled analysis. Assessment of heterogeneity in study results is also a critical outcome of meta-analysis. The benefit of meta-analysis is that you may pool results of large and complex studies. There are methods of examining data for studies to be missing as failure to identify the majority of existing studies can lead to erroneous results. Rigorously conducted meta-analyses are useful tools in evidence-based medicine. Software like Review Manager (Revman) and Comprehensive Meta-Analysis provide detailed meta-analysis including forest and funnel plots.
Meta-analysis addresses limitations of study size; can include diverse populations; give chance to evaluate new hypotheses, and are more precious than any single study contributing to the analysis.
Last modified: 21/11/2019