Hydrogel dressings for venous leg ulcers.

BACKGROUND Venous leg ulcers are a chronic health problem that cause considerable economic impact and affect quality of life for those who have them. Primary wound contact dressings are usually applied to ulcers beneath compression therapy to aid healing, promote comfort and control exudate. There are numerous dressing products available for venous leg ulcers and hydrogel is often prescribed for this condition; however, the evidence base to guide dressing choice is sparse. OBJECTIVES To assess the effects of hydrogel wound dressings on the healing of venous leg ulcers in any care setting. SEARCH METHODS In May 2021, we searched the Cochrane Wounds Specialised Register, CENTRAL, Ovid MEDLINE, Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies, reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting. SELECTION CRITERIA We included randomised controlled trials (RCTs), either published or unpublished, that compared the effects of hydrogel dressing with other dressings on the healing of venous leg ulcers. We excluded trials evaluating hydrogel dressings impregnated with antimicrobial, antiseptic or analgesic agents as these interventions are evaluated in other Cochrane Reviews. DATA COLLECTION AND ANALYSIS We used standard methodological procedures expected by Cochrane. We assessed the certainty of the evidence using the GRADE approach. MAIN RESULTS We included four RCTs (10 articles) in a qualitative analysis. Overall, 272 participants were randomised, in sample sizes ranging from 20 to 156 participants. The mean age of the included population in the trials ranged from 55 to 68 years, 37% were women based on studies that reported the sex of participants. The studies compared hydrogel dressings with the following: gauze and saline, alginate dressing, manuka honey and hydrocolloid. Two studies were multicentre and the others were single-centre trials. Length of treatment using hydrogel dressing was four weeks in three studies and two weeks in one study. The follow-up period was the same as the duration of treatment in three studies and in one study the follow-up for wound healing was at 12 weeks after four weeks of treatment. Overall risk of bias was high for all trials because at least one of the three key criteria (selection bias, detection bias and attrition bias) was at high risk. Hydrogel compared with gauze and saline It is uncertain whether there is a difference in complete wound healing (risk ratio (RR) 5.33, 95% confidence interval (CI) 1.73 to 16.42; 1 trial, 60 participants) or change in ulcer size (mean difference (MD) -1.50, 95% CI -1.86 to -1.14; 1 trial, 60 participants) between interventions because the certainty of the evidence is very low. Data reported from one trial were incomplete for time-to-ulcer healing. Hydrogel compared with alginate dressing It is uncertain whether there is a difference in change in ulcer size between hydrogel and alginate gel because the certainty of the evidence is very low (MD -41.80, 95% CI -63.95 to -19.65; 1 trial, 20 participants). Hydrogel compared with manuka honey It is uncertain whether there is a difference in complete wound healing (RR 0.75, 95% CI 0.46 to 1.21; 1 trial, 108 participants) or incidence of wound infection (RR 2.00, 95% CI 0.81 to 4.94; 1 trial, 108 participants) between interventions because the certainty of the evidence is very low. Hydrogel compared with hydrocolloid One study (84 participants) reported on change in ulcer size between hydrogel and hydrocolloid; however, further analysis was not possible because authors did not report standard errors or any other measurement of variance of a set of data from the means. Therefore, it is also uncertain whether there is a difference in change in ulcer size between hydrogel and hydrocolloid because the certainty of the evidence is very low. No studies provided evidence for the outcomes: recurrence of ulcer, health-related quality of life, pain and costs. Overall, independent of the comparison, the certainty of evidence is very low and downgraded twice due to risk of bias and once or twice due to imprecision for all comparisons and outcomes. AUTHORS' CONCLUSIONS There is inconclusive evidence to determine the effectiveness of hydrogel dressings compared with gauze and saline, alginate dressing, manuka honey or hydrocolloid on venous leg ulcer healing. Practitioners may, therefore, consider other characteristics such as costs and symptom management when choosing between dressings. Any future studies assessing the effects of hydrogel on venous wound healing should consider using all the steps from CONSORT, and consider key points such as appropriate sample size with the power to detect expected differences, appropriate outcomes (such as time-to-event analysis) and adverse effects. If time-to-event analysis is not used, at least a longer follow-up (e.g. 12 weeks and above) should be adopted. Future studies should also address important outcomes that the studies we included did not investigate, such as health-related quality of life, pain and wound recurrence.