Comparison of Cold Copolymer Gel Pack before Botulinum Toxin Injection Versus Standard Cold Pack in Subjects with Crow’s Feet: Non-Inferiority Trial

Abstract

At present, cold compresses are quite expensive. Developing using cold copolymer gel pack can be
useful to reduce skin sensation. This was a split-face non-inferiority double-blind randomized controlled
trial, to compare the effectiveness of cold copolymer gel pack before botulinum toxin injection versus
standard cold pack in subjects with crow’s feet. Twenty-one patients given bilateral periocular injections
for wrinkle reduction were randomized into experimental side (cold copolymer gel pack) and control side
(standard cold pack) using block randomization. Relative pain scores were recorded to assess the effects
of treatment. Non-inferiority hypothesis was evaluated at -1.20 (non-inferiority margin). It was found
that the experimental side and the control side had the pain score 4.52±2.36 and 4.14±2.83 which was
no statistical differences (p>0.05) (absolute difference of 0.38, 95%CI=-0.97 - 1.73). The 95%
confidence interval was on the right side of non-inferiority margin, Thus, cold copolymer gel pack was
not inferior to standard cold pack. The authors recommended that cold copolymer gel pack could be an
effective and acceptable substitution of the standard cold pack.