Table 6.

Evaluation of certainty of evidence using Grading of Recommendations, Assessment, Development, and Evaluations (GRADE).

Certainty assessment							No. of patients		Effect		Certainty
No. of studies	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	PG	Placebo	Relative (95% CI)	Absolute (95% CI)
RP Severity
8	Randomized trials	Very seriousa	Not seriousb	Not serious	Not serious	None	491	435	—	MD 0.18 lower (0.37 lower to 0.01 higher)	⨁⨁◯◯ Lowa,b
RP Frequency
6	Randomized trials	Seriousc	Not serious	Not serious	Not serious	None	329	302	—	MD 0.32 lower (0.76 lower to 0.13 higher)	⨁⨁⨁◯ Moderatec
RP Duration
5	Randomized trials	Seriousc	Not serious	Not serious	Seriousd	None	275	243	—	MD 4.79 lower (14.69 lower to 5.12 higher)	⨁⨁◯◯ Lowc,d

Abbreviations: CI, confidence interval; MD, mean difference.

^aTwo studies with high risk of bias.

^bModerate heterogeneity.

^cOverall allocation concerns and high risk of selective reporting.

^dWide confidence interval.