Management of nonalcoholic fatty liver disease: An evidence-based clinical practice review

Table 1 Levels of evidence according to the study design

Level of evidence	Description
Type I	Evidence obtained from at least one well-designed, randomized, controlled1 trial or from a systematic review of randomized clinical studies
Type II	II-1 Evidence obtained from nonrandomized, prospective, controlled1 studies
	II-2 Evidence obtained from cohort observational studies2 or case-control studies, preferably multicenter
	II-3 Evidence obtained from case series
Type III	Opinions of authorities on the subject matter based on expertise, expert committees, case reports, pathophysiological studies or basic science studies

¹A controlled study is a study in which the intervention is managed by the researcher;

²An observational study is a study in which the intervention is not controlled by the researcher.