Adalatkhah 2007.

Study characteristics
Methods	This study was carried out in a secondary care setting. This was a left‐right study. The blinding within this study was unclear. Intention‐to‐treat analysis was not carried out. This study was conducted in the USA.
Participants	52 participants were recruited: 8 dropped out. Inclusion criteria of the trial Participants aged > 12 Ordinary warts Warts on the hands or feet
Interventions	Cryotherapy versus Cryotherapy plus bleomycin Treatment was allocated up to 3 times if necessary.
Outcomes	Outcomes of the trial Cure at 6 weeks
Notes	The adequacy of cryotherapy was uncertain as 'the wart was sprayed until the ice ball formation had spread from the centre to include the edge of the wart and a 1 mm margin.'
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote (page 2): "Two treatment types were randomly allocated to either right sided or left sided warts", but the method of randomisation was unclear. Comment: There was insufficient information to permit judgement.
Allocation concealment (selection bias)	Unclear risk	It was unclear if allocation was concealed. Comment: This was unclear; no details were given.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	No details were given, but as the treatments were very different, it would have been difficult to fully blind. Comment: This was unclear; no details were given.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No details were given; the treatment and assessment was done by different dermatologists. Comment: This was unclear; no details were given.
Incomplete outcome data (attrition bias) All outcomes	High risk	Quote (page 2): "Most patients (44 of 52) continued participation." It was unclear if the dropouts were balanced across the groups, and no reasons were given for the dropouts.
Selective reporting (reporting bias)	High risk	Quote (page 4): "Only five cases of significant adverse complications were encountered, three of which belonged to bleomycin. Minor complications were not recorded." There was risk of bias from incomplete adverse event reporting.