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Abstract
The world today is overflowing with results from trials to the point where anyone can be overwhelmed. Being able to sort out the good systematic reviews and meta-analyses from the bad ones and then be confident in the ability to judge the quality of the evidence is critical. Systematic reviews (i.e., the process of systematically locating and synthesizing data from completed studies) and meta-analyses (i.e., the statistical component of a systematic review) are the procedures that make it possible to synthesize data from a series of studies (i.e., evidence synthesis); these are essential to summarise evidence relating to efficacy and safety of health care interventions accurately and reliably.
The process begins with a pre-specified protocol [1] asking an explicit question, in terms of the populations, alternative management strategies (an intervention, sometimes experimental and a comparator, sometimes standard care), and all patient-important outcomes [2]. After the evidence is collected, summarised, and reported [3], a good systematic review will help determine the quality of evidence based on study design, risk of bias, imprecision, inconsistency, indirectness, and magnitude of effect [4]. Quality of the evidence (QoE) reflects our confidence that the estimates of the effect are correct. High QoE: “We are very confident that the true effect lies close to that of the estimate of the effect” (no more research needed); Very low QoE: “The true effect is likely to be substantially different from the estimate of effect” [5].
Following this, guideline panels might conclude with either a strong or conditional recommendation, either for or against an intervention - indicating whether patients should receive the specific course of action {6}.
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Disclosure of Interest None declared