TABLE 1.

QUALITY OF EVIDENCE DETERMINATION

Quality of Evidence	Study Design	Lower If:	Higher If:
High	Randomized controlled trial	Limitation in study quality Indirectness Important inconsistency Sparse or imprecise data High probability of publication bias	Strong association, no plausible confounders Evidence of a dose–response gradient Plausible confounders would have reduced the effect
Moderate	Downgraded randomized controlled trial or upgraded observational study
Low	Well done observational study with control groups
Very low	Any other evidence (e.g., case reports, case series)