The EVERT (effective verruca treatments) trial protocol: a randomised controlled trial to evaluate cryotherapy versus salicylic acid for the treatment of verrucae

BACKGROUND: Verrucae are a common, infectious and sometimes painful problem. The optimal treatment for verrucae is unclear due to a lack of high quality randomised controlled trials. The primary objective of this study is to compare the clinical effectiveness of two common treatments for verrucae: cryotherapy using liquid nitrogen versus salicylic acid. Secondary objectives include a comparison of the cost-effectiveness of the treatments, and an investigation of time to clearance of verrucae, recurrence/clearance of verrucae at six months, patient satisfaction with treatment, pain associated with treatment, and use of painkillers for the treatments. METHODS/DESIGN: This is an open, pragmatic, multicentre, randomised controlled trial with two parallel groups: cryotherapy using liquid nitrogen delivered by a healthcare professional for a maximum of 4 treatments (treatments 2-3 weeks apart) or daily self-treatment with 50% salicylic acid for a maximum of 8 weeks. Two hundred and sixty-six patients aged 12 years and over with a verruca are being enrolled into the study. The primary outcome is complete clearance of all verrucae as observed on digital photographs taken at 12 weeks compared with baseline and assessed by an independent healthcare professional. Secondary outcomes include self-reported time to clearance of verrucae, self-reported clearance of verrucae at 6 months, cost-effectiveness of the treatments compared to one another, and patient acceptability of both treatments including possible side effects such as pain. The primary analysis will be intention to treat. It is planned that recruitment will be completed by December 2009 and results will be available by June 2010. TRIAL REGISTRATION: Current Controlled Trials ISRCTN18994246.