Laudanska 1988.

Methods	Randomised controlled trial conducted in Poland
Participants	67 people with venous leg ulcers who failed to respond to outpatient treatment (dressings and compression bandages) were recruited; data from 60 people were analysed by the trial authors. Those with ulcers of diameter < 2 cm were excluded: 1. 33 people 2. 33 people 1 patient was excluded from the trial authors' analyses, for whom the treatment group was not specified Mean ± SE baseline ulcer area, cm2: Group 1: 35.2 ± 8.1; Group 2: 27.5 ± 7.0 Mean ± SE baseline ulcer duration, months: Group 1: 15.0 ± 3.1; Group 2: 19.1 ± 4.3 No information about ulcer infection status at baseline (but it appeared that those with infected ulcers might have been allowed into the trial).
Interventions	1. Ulcers cleansed with dilute hydrogen peroxide and covered with zinc paste dressing. The following were also used if deemed necessary by the clinician: saline dressing; dilute potassium permanganate solution; and gentian violet solution 2. Cadexomer iodine applied in a 3 to 4 mm layer All participants were treated in a hospital inpatient setting and received daily dressing changes; a light elastic bandage to keep the dressing in place; and bed rest for the 6 weeks' duration of the trial; allowed out of bed for meals and toileting
Outcomes	Primary outcomes: Complete healing or very superficial wound remaining at 6 weeks: 1. 7/33 2. 16/33 Mean ulcer area reduction at 6 weeks: 1. 54% 2. 71% P value < 0.01 (reported by trial authors) Secondary outcomes: Pain assessed using 100=cm visual analogue scale: Figure presented in paper indicates reduction in pain at 6 weeks in both groups relative to baseline, but figure not detailed enough for values to be read. The trial authors reported that pain reduction occurred more rapidly in Group 2, and that relative to Group 1, significantly less pain was reported within 1 week of commencement of treatment (P value < 0.01) Numbers (%) of participants reporting adverse events (description): 1. 1/30 (3%) (stinging sensation in the ulcer when dressing applied) 2. 6/30 (20%) (1 peri‐ulcer erythema; 5 stinging sensation in the ulcer when dressing applied) Elevation of serum concentrations of protein‐bound iodine occurred after treatment with cadexomer iodine in participants with large ulcers, but tests of thyroid function showed no changes associated with the use of cadexomer iodine
Notes	Overall, 7/67 (10%) participants withdrew. 4 participants (2 per group) withdrew before the first assessment (social reasons 3 and heart failure 1; reasons not presented per group) A further 3 participants completed the trial but were excluded from analysis, 2 because of difficulty in measuring the ulcer because of large size (1 per group) and 1 because of having an ulcer associated with severe rheumatoid arthritis, which interfered with assessment (group not stated)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Patients were randomly allocated to treatment with either cadexomer iodine or the standard local dressing regime" Comment: It was not stated how the sequence was generated
Allocation concealment (selection bias)	Unclear risk	Quote: "Treatment code not broken until study was completed" Comment: No measures were described to prevent foreseeing the intervention allocation
Blinding (performance bias and detection bias) Participant blinded to the intervention	Unclear risk	No information provided
Blinding (performance bias and detection bias) Outcome assessor blinded to the intervention	Unclear risk	Quote: "A single observer made all assessments in every patient throughout the trial and treatment code not broken until study completed" Comment: It was not stated whether this observer was blind to treatment allocation
Incomplete outcome data (attrition bias) Drop out rate described	Unclear risk	Quote: "Two patients in each treatment group dropped out of the trial before the first assessment. In three instances this was due to social reasons and in one case because of cardiac failure not due to treatment..." Quote: "The results obtained from three patients, all of whom responded to treatment, were excluded from the analysis" Comment: Some information on withdrawals (numbers/reasons) was given in relation to the whole sample, not per treatment group
Incomplete outcome data (attrition bias) Drop out rate acceptable	Low risk	Comment: Overall withdrawal rate was less than 20%
Incomplete outcome data (attrition bias) ITT analysis	Unclear risk	Quote: "The results obtained from three patients, all of whom responded to treatment, were excluded from the analysis" Comment: Analysis was based on 60/67 participants. It is unclear how these withdrawals might have impacted estimates of treatment effect (this is a small RCT)
Baseline factors comparable	Unclear risk	Difficult to judge baseline comparability, as mean values, rather than medians, were provided