He 2008.

Study characteristics
Methods	Design: RCT Country: China Setting: not reported Sample size calculation: not reported Ethical approval: not reported Informed consent: not reported
Participants	Total sample: 60 participants with chronic venous ulcer of lower extremities Inclusion criteria: aged ≥ 18 years; required to have a venous insufficiency ulcer for > 1 month of duration, with area ≤ 4 cm²; woman not pregnant; not on immunosuppression; no history of allergy to polysaccharides (glycans) Exclusion criteria: none specified Numbers randomised Group 1 (hydrogel dressing): 30 participants Group 2 (gauze and saline): 30 participants Sex: Group 1 (hydrogel dressing): 24 men and 6 women Group 2 (gauze and saline): 20 men and 10 women Side of the ulcers: 32 ulcers from the left side and 28 ulcers from the right side Baseline ulcer size (mean) (before treatment): range 2.5–4.0 cm² Group 1 (hydrogel dressing): 3.4 (SD 0.6) cm² Group 2 (gauze and saline): 3.1 (SD 0.4) cm² Mean age: Group 1 (hydrogel dressing): 57.3 (SD 6.8) years Group 2 (gauze and saline): 60.1 (SD 7.4) years Ulcer duration: Group 1 (hydrogel dressing): 2.9 (SD 0.7) years Group 2 (gauze and saline): 3.3 (SD 0.9) years ABPI: not reported Unit of randomisation: participant Unit of analysis: participant Ulcer infection: not reported Data collected: diagnosis, sex, age, ulcer dimension and volume
Interventions	Group 1: hydrogel dressing (Chitosan, Xangai Qisheng) Group 2: gauze and saline Description of compression therapy: not reported Length of treatment: 14 days Follow‐up: not reported. Authors reported that participants who resulted were classified as "failure" continued the treatment until cured (results of treatment were classified as: "cured", "excellent", "regular", "failure").
Outcomes	Complete wound healing Group 1 (hydrogel dressing): 16/30 at 14 days Group 2 (gauze and saline): 3/30 at 14 days Incidence of wound infection: not reported Change in ulcer size: reported at 7 and 14 days. Group 1 (hydrogel dressing): reduction from 3.4 (SD 0.6) cm² to 1.1 (SD 0.2) cm² at day 14 Group 2 (gauze and saline): reduction from 3.1 (SD 0.4) cm² to 2.3 (SD 0.7) cm² at day 14 (reported P < 0.05) Time to ulcer healing: reported (reported P < 0.01). Unable to confirm the number of participants followed up to complete ulcer healing. Time for healing reported by authors Group 1 (hydrogel dressing): 12.0 (SD 1.7) days Group 2 (gauze and saline): 31.0 (SD 2.9) days Recurrence of ulcer: not reported Health‐related quality of life: not reported Pain: not reported Costs: not reported
Notes	Funding: not described
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: the authors mentioned that the participants were randomly divided into 2 groups, but they did not describe the method of randomisation.
Allocation concealment (selection bias)	Unclear risk	Comment: no mention of allocation concealment.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: no mention of blinding in study report.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: no mention of blinding in study report.
Incomplete outcome data (attrition bias) All outcomes	High risk	Comment: the study report contained no statement regarding withdrawals but all the participants were included in the final analysis at the 14‐day follow‐up; however, there is no description for the number of participants followed up to total ulcer healing.
Selective reporting (reporting bias)	High risk	Comment: the study report described 1 outcome (time to complete ulcer healing) in the results section that was not properly described in the methods section. Unable to obtain RCT protocol (no response from email sent to trial author).
Other bias	High risk	Comment: unit of randomisation and unit the analysis were the participant. There was a small imbalance in groups regarding sex (more men in hydrogel group). Even though the study mentioned the mean baseline ulcer surface area did not differ between groups, our independent analysis using a 2‐tailed independent t‐test resulted in difference between groups.

ABPI: ankle brachial pressure index; CI: confidence interval; ITT: intention to treat; RCT: randomised controlled trial; SD: standard deviation.