Propranolol in Use for Treatment of Complex Infant Hemangiomas: Literature Review Regarding Current Guidelines for Preassessment and Standards of Care before Initiation of Therapy

Table 1

Levels of evidence (reproduced and referenced according to [64, 67]).

Category of evidence	Study design
Level I	(i) High-quality randomized trial with statistically significant difference, or no statistically significant difference but narrow confidence intervals; (ii) Systematic review of Level I randomized control trials (and study results were homogenous)
Level II	(i) Lesser-quality randomized control trial (i.e., <80% followup, no blinding, or improper randomization); (ii) Prospective comparative study; (iii) Systematic review of Level II studies or Level I studies with inconsistent results
Level III	(i) Case control study; (ii) Retrospective comparative study; (iii) Systematic review of Level III studies
Level IV	Case series
Level V	Expert opinion
Strength of recommendation	Category of evidence
A	Directly based on category I evidence
B	Directly based on category II evidence or extrapolated recommendation from category I evidence
C	Directly based on category III evidence or extrapolated recommendation from category I or II evidence
D	Directly based on category IV evidence or extrapolated recommendation from categories I, II, or III evidence