Botulinum Toxin A for Hyperkinetic Facial Lines: Results of a Double-Blind, Placebo-Controlled Study.

Facial aesthetics: is botulinum toxin treatment effective and safe? A systematic review of randomised controlled trials

“…The hand search resulted in a further four double-blind RCTs to be included in our study. [18][19][20][21] Description of studies The 11 RCTs included in our review paper and their backgrounds are summarised in Table 3.…”

“…In two papers, the BTA manufacturer used was not specifi ed. 20,21 The studies were conducted in countries including the USA, Canada, France, UK, Germany and Belgium.…”

“…Further information on the quality of the studies was requested from four studies; response to our email requests was obtained from authors of only one of these. 20 Two studies had only enrolled female patients in their study. 18,21 In one study on forehead and crow's feet, the authors revealed that the sides of the forehead to be injected with the BTA or placebo were randomised; however at one week there was very little blinding since the results of treatment became obvious, with one side of the forehead having little motion while the other had normal motion.…”

“…The data on the scores as recorded by the blinded assessors was requested from the authors; however they did not have access to the data as the study was over 15 years old. 20 The maximum improvement in chin wrinkles also occurred four weeks postinjection of BTA. The effect of BTA over placebo was prominent when assessment was carried out at maximum contraction, but this effect diminished slowly over the 12-week recall period.…”

“…18,21 Three studies may also be criticised for using the same patients to receive active BTA on one side of the midline and the placebo on the other side; this reduces blinding and increases the bias during assessment of facial wrinkles when one side responds more than the other. 16,20,21 Four of the included studies can be criticised for providing inadequate data on sequence generation, allocation concealment, blinding process or variable reporting of data on a per-protocol or intention-to-treat basis. 14,17,20,21 The mean age of patients included in this review ranged between 31 and 50.9 years.…”