Table 1.

Level of evidence and grade of recommendation determined by the technical committee of Explicit Guarantees in Health (GES), Ministry of Health, Chile

Grade	Description
A	Highly recommended: Based on good quality studies Systematic reviews of randomized clinical trials, randomized clinical trials, other systematic reviews with or without meta-analysis, health technology assessment reports.
B	Recommended: Based on moderate quality studies Randomized studies with methodological limitations or other forms of non-randomized controlled studies.
C	Recommendation based exclusively on expert opinion or descriptive studies, case series, case reports or other uncontrolled studies with a high potential for bias.
I	Insufficient information The available studies do not allow to establish the effectiveness or benefit/harm balance of the intervention, there are no studies on the subject or there is not enough consensus to consider that the intervention is supported by practice.
BP	Recommendation based on the experience and practice of a group of experts.