I commend Focht et al1 for their attempt to compare any therapy against cryotherapy in the treatment of warts. I debated replying, but decided to do so in view of the coverage the article received in the lay press and "throwaway" trade publications—which could damage the reputation of cryosurgery for thisindication.
Without diminishing the value of the author's observation that occlusive therapy worked in 85% of the patients, fancy data analysis cannot correct major study design flaws. Not to be confused with cryosurgery, cryotherapy in this article is represented as the application of liquid nitrogen for 10 seconds to each wart, given by "trained pediatric nursing personnel" (enough said?) who are also in charge of providing follow-up evaluations in a "blinded" manner. "Many" of the treated warts could not be followed up because some (of the not many) patients were reluctant to return; thus, their evaluation took place over the telephone.
Abramovits W. Cryotherapy vs Duct Tape. Arch Pediatr Adolesc Med. 2003;157(5):491. doi:10.1001/archpedi.157.5.491-a