When seeking answers to clinical questions about efficacy or other aspects of a proposed intervention, health professionals often look for reliable evidence. Systematic literature reviews (SLRs) serve this purpose, by virtue of their ability to generate high-quality, verifiable, and trustworthy evidence in a systematic, transparent, and impartial manner.(1) In the new evidence pyramid, systematic reviews are visualized as the lens through which certainty can be measured in all other primary research reported in multiple study designs.(1,2) The SLR process is most often used by reputed professional organizations worldwide for generating practice guidelines for diagnosis and management of different disorders.(1) However, since the primary research used for generating such guidelines are often of variable quality, the resulting guidelines may also be of a non-uniform quality. Therefore, it becomes essential to quantify and grade the quality of evidence and strength of the recommendations.(1,2)
Out of the different available frameworks for doing this, perhaps the most frequently used system is the GRADE (Grading quality of evidence and strength of recommendations) framework. The GRADE approach starts with formulating the research question into appropriate PICOS headings, and selecting the most relevant outcomes for research. After performing an SLR gathering evidence about each of the selected outcomes, the certainty (alternatively called level or quality) of the evidence so gathered is graded based on various factors under four headings:(1–5)
To begin with, certainty of evidence is considered to be higher from RCTs than observational studies. Other factors which impact evidence certainty include:
Evidence that is initially rated as ‘high’ may be downgraded after consideration of the aforementioned criteria; the opposite is also possible.(3)
At the end of the grading process, all outcomes of interest will be associated with a certain level of certainty. Based on the evidence so collected, recommendations are often drawn by a guideline panel. Various considerations that go into this process include balancing of benefits and risks, certainty of evidence, values and preferences, costs, feasibility, acceptability, and equity.(1) The resulting practice recommendations are assigned a ‘strength ranking’ under the GRADE approach: the recommendation can be ‘strong’ or ‘conditional’, and ‘for’ or ‘against’ a specific action in a specific situation. Strong recommendations suggest that most, if not all, people would choose this intervention. Weak recommendations imply that there is significant variation likely to be made by investigators in the decision.(2,4)
It is important to acknowledge that using GRADE will commonly involve some subjective judgments, and assessments may vary between individuals. Despite this, the GRADE approach has proven to be an essential component of all clinical practice guidelines resulting from high-quality SLRs, since it provides a systematic, explicit, and transparent approach for grading the certainty of evidence and quality of practice recommendations.
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