Table 1 Categories used to document the level of uncertainty at source

A

Uncertainty extracted from consensus guideline(s)

B

No Cochrane systematic review performed

(this includes uncertainties derived from Protocols)

C

Cochrane systematic review performed, but authors did not find any RCTs in the literature to include

D

Cochrane systematic review done, some RCTs found, but no formal meta-analysis performed

(this is usually due to poor quality of RCTs or disparities of design/outcome measures)

E

Cochrane systematic review with meta-analysis performed, results inconclusive