Hoffman 1999.

Methods	Prospective cohort study/case series Setting: community wound clinic Country: UK Duration of follow‐up: 36 weeks Treatments: various dressings (NA ultra (4), wool padding (5), Zipzoc (2), Coltapaste), and compression bandages (Litepress/Co‐plus/crepe (2), Tensopress (2), Tubigrip, Elastocrepe)
Participants	7 participants with VLUs (no further details) Age: not reported Sex: not reported Stage of ulcer: not reported Ulcer duration: median (range): 3 years (13 months‐8 years) (from IPD) Ulcer size at baseline: not reported Wound infection: not reported Number of wounds: 7 Inclusion criteria: VLUs Exclusion criteria: not reported
Prognostic factors	Human neutrophil elastase (continuous data); from graph IPD. All participants had data at 4 weeks, so this was selected as the baseline time; variability over time within participants. Measurement method activity assay using selective substrate and measuring change in optical density. Elastase activity determined using a standard curve generated with pure human neutrophil elastase (Sigma, UK). Total elastase activities determined by correcting for total volume of wound fluid and phosphate‐buffered saline recovered from the bandage. Time of measurement: baseline and weekly for 6 weeks Wound fluid sampling method: entrapment in dressings (fluid harvested weekly from compression bandages on dressing change)
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Selection bias	High risk	Too few participants to be representative (7 participants with VLUs at 1 centre were recruited into the study; study design changed so that measured healing after 9 months rather than 6 weeks)
Attrition bias	Low risk	No missing data
Prognostic factor measurement	High risk	Moderate: protease levels recorded from bandages when dressings changed. Protease levels will be influenced by how much remains on the dressings
Outcome measurement	Unclear risk	Moderate: unclear if blinded
Adjustment factors	High risk	None of the key adjustment factors taken into account in the design or analysis
Analysis and reporting	High risk	IPD given for outcome and individual protease levels given graphically. Not all participants had protease levels at baseline, but results for all for week 4; therefore, we selected this time of prognostic factor measurement
Overall risk of bias	High risk