Botulinum Toxin Versus Placebo: A Meta-Analysis of Treatment and Quality-of-life Outcomes for Hyperhidrosis.

[AIMS] This study aims at assessing the treatment effect, disease severity and quality-of-life outcomes of botulinum toxin (BTX) injections for focal hyperhidrosis.

[METHODS] We included randomized controlled trials of BTX injections compared with placebo for patients with primary or secondary focal hyperhidrosis. PubMed, Embase and the Cochrane Library were searched to August 2020. Gravimetric sweat rate reduction, disease severity measured by Hyperhidrosis Disease Severity Scale and quality-of-life assessment measured by Dermatology Life Quality Index were the outcomes of interest. Cochrane risk-of-bias tools were employed for quality assessment of given randomized controlled trials.

[RESULTS] Eight studies met our inclusion criteria (n=937). Overall, risk bias was mixed and mostly moderate. BTX injections showed reduced risk in comparison with placebo for the gravimetric quantitative sweat reduction of > 50 % from baseline (risk difference: 0.63, 95% CI 0.51 to 0.74). Additionally, improvements were seen for disease severity and quality-of-life assessments evaluated by Hyperhidrosis Disease Severity Score reduction of ≥ 2 points (risk difference: 0.56, 95% CI 0.42 to 0.69) and mean change in Dermatology Life Quality Index (mean difference: - 5.55, 95% CI - 7.11 to - 3.98). The acquired data were insufficient to assess for long-term outcomes and limited to an eight-week follow-up period.

[CONCLUSIONS] In focal axillary hyperhidrosis, BTX significantly reduces sweat production and yields superior outcomes in assessments of disease severity and quality-of-life. However, the quality-of-evidence is overall moderate and included studies account for short-term trial periods only. Further studies assessing BTX in comparison with first-line treatments for hyperhidrosis are warranted.

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