Comparison 2. OnabotulinumtoxinA 20 units versus placebo one cycle of treatment in glabellar lines.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
2.1 Participant assessment of success by analysing scores and scales	4		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
2.1.1 4 weeks	4	575	Risk Ratio (M‐H, Random, 95% CI)	19.45 [8.60, 43.99]
2.1.2 8 weeks	2	204	Risk Ratio (M‐H, Random, 95% CI)	28.45 [5.92, 136.74]
2.1.3 12 weeks	2	203	Risk Ratio (M‐H, Random, 95% CI)	12.77 [2.78, 58.72]
2.1.4 16 weeks	2	167	Risk Ratio (M‐H, Random, 95% CI)	20.71 [2.82, 151.91]
2.1.5 24 weeks	1	77	Risk Ratio (M‐H, Random, 95% CI)	4.19 [0.21, 84.41]
2.2 Major adverse events (eyelid ptosis, eyelid sensory disorder, strabismus)	8	1390	Peto Odds Ratio (Peto, Fixed, 95% CI)	3.62 [1.50, 8.74]
2.3 Physician assessment of success by analysing scores and scales	7		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
2.3.1 4 weeks	7	1339	Risk Ratio (M‐H, Random, 95% CI)	17.10 [10.07, 29.05]
2.3.2 8 weeks	6	1046	Risk Ratio (M‐H, Random, 95% CI)	21.50 [9.68, 47.75]
2.3.3 12 weeks	6	1046	Risk Ratio (M‐H, Random, 95% CI)	10.81 [5.79, 20.16]
2.3.4 16 weeks	5	933	Risk Ratio (M‐H, Random, 95% CI)	15.13 [5.98, 38.27]
2.3.5 20 weeks	1	77	Risk Ratio (M‐H, Random, 95% CI)	5.86 [0.31, 109.74]
2.3.6 24 weeks	1	77	Risk Ratio (M‐H, Random, 95% CI)	4.19 [0.21, 84.41]
2.4 Total adverse events	8	1388	Risk Ratio (M‐H, Random, 95% CI)	1.14 [0.89, 1.45]
2.5 Duration of treatment (weeks)	1	77	Mean Difference (IV, Random, 95% CI)	18.40 [16.17, 20.63]