Effectiveness comparisons of antiviral treatments for Bell palsy: a systematic review and network meta-analysis

Antiviral treatments for Bell palsy have been widely used, but there is no definite conclusion of which is the most effective antiviral drug. We conducted a systematic review of randomized controlled trials (RCTs) including network meta-analysis to investigate the comparative effectiveness of antiviral treatments for Bell palsy. RCTs comparing effectiveness between antiviral treatments and placebo were included. Risk of bias within and across studies was assessed with the Cochrane tool and the GRADE approach, respectively. Random-effects pairwise meta-analyses were conducted, followed by network meta-analysis. Three electronic databases were searched from inception to May 18, 2020. 11 trials and 3393 patients with four arms and eleven contrasts were included. Significant differences were observed between placebo and famciclovir with respect to overall recovery and no statistically significant differences were found from other comparisons. Treatment ranking based on the evidence network indicated that famciclovir shared the best results, followed by valacyclovir, acyclovir, and finally placebo. Adverse events of famciclovir were too rare and slight to be analyzed. Our confidence in pairwise comparisons was moderate to low, due to study limitations, inconsistency, and imprecision; our confidence in ranking was moderate, due to study limitations. Inconsistency is not deemed to exist by a loop-specific approach and node-splitting procedure. Results of exploring publication bias are satisfying. According to pairwise and network comparisons, famciclovir could be better than placebo and the effectiveness of other antiviral treatments are similar. For clinical efficacy, famciclovir obtains the best recovery rate of facial function for Bell palsy. Acyclovir has the lowest rate of synkinesis, though, it is not adequately recommended and more superior trails are needed in the future.