The quality of evidence is downgraded by study limitations (unclear allocation concealment and blinding, and selective outcome reporting), by indirectness (differences between the interventions and population of interest and those studied), and by imprecise results (few patients and outcome events).

A Cochrane review ¹ included 5 studies with a total of 295 subjects. One study compared different proprietary alginate dressings (n=20), 3 studies compared alginate and hydrocolloid dressings (n=215), and one study compared alginate and plain non-adherent dressings (n=60). Follow-up periods were 6 weeks in 3 studies and 12 weeks in 2 studies. No statistically significant between-group differences were detected for any comparison, for any healing outcome. Meta-analysis was feasible for one comparison, alginate compared with hydrocolloid dressings (RR for complete healing at 6 weeks 0.42, 95% CI 0.14 to 1.21; 2 studies, n=84). Adverse event profiles were generally similar between groups (not assessed for alginate versus plain non-adherent dressings).