Topical antimicrobial agents (antibacterial products applied directly to wounds) for treating foot ulcers in people with diabetes

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We found 22 trials that met our inclusion criteria with a total of over 2310 participants (one study did not report number of participants). The included studies mostly had small numbers of participants (from 4 to 317) and relatively short follow-up periods (4 to 24 weeks). At baseline, six trials included only people with ulcers that were clinically infected; one trial included people with both infected and uninfected ulcers; two trials included people with non-infected ulcers; and the remaining 13 studies did not report infection status.

Included studies employed various topical antimicrobial treatments, including antimicrobial dressings (e.g. silver, iodides), super-oxidised aqueous solutions, zinc hyaluronate, silver sulphadiazine, tretinoin, pexiganan cream, and chloramine. We performed the following five comparisons based on the included studies:

Antimicrobial dressings compared with non-antimicrobial dressings: Pooled data from five trials with a total of 945 participants suggest (based on the average treatment effect from a random-effects model) that more wounds may heal when treated with an antimicrobial dressing than with a non-antimicrobial dressing: risk ratio (RR) 1.28, 95% confidence interval (CI) 1.12 to 1.45. These results correspond to an additional 119 healing events in the antimicrobial-dressing arm per 1000 participants (95% CI 51 to 191 more). We consider this low-certainty evidence (downgraded twice due to risk of bias). The evidence on adverse events or other outcomes was uncertain (very low-certainty evidence, frequently downgraded due to risk of bias and imprecision).

Antimicrobial topical treatments (non dressings) compared with non-antimicrobial topical treatments (non dressings): There were four trials with a total of 132 participants in this comparison that contributed variously to the estimates of outcome data. Evidence was generally of low or very low certainty, and the 95% CIs spanned benefit and harm: proportion of wounds healed RR 2.82 (95% CI 0.56 to 14.23; 112 participants; 3 trials; very low-certainty evidence); achieving resolution of infection RR 1.16 (95% CI 0.54 to 2.51; 40 participants; 1 trial; low-certainty evidence); undergoing surgical resection RR 1.67 (95% CI 0.47 to 5.90; 40 participants; 1 trial; low-certainty evidence); and sustaining an adverse event (no events in either arm; 81 participants; 2 trials; very low-certainty evidence).

Comparison of different topical antimicrobial treatments: We included eight studies with a total of 250 participants, but all of the comparisons were different and no data could be appropriately pooled. Reported outcome data were limited and we are uncertain about the relative effects of antimicrobial topical agents for each of our review outcomes for this comparison, that is wound healing, resolution of infection, surgical resection, and adverse events (all very low-certainty evidence).

Topical antimicrobials compared with systemic antibiotics : We included four studies with a total of 937 participants. These studies reported no wound-healing data, and the evidence was uncertain for the relative effects on resolution of infection in infected ulcers and surgical resection (very low certainty). On average, there is probably little difference in the risk of adverse events between the compared topical antimicrobial and systemic antibiotics treatments: RR 0.91 (95% CI 0.78 to 1.06; moderate-certainty evidence – downgraded once for inconsistency).

Topical antimicrobial agents compared with growth factor: We included one study with 40 participants. The only review-relevant outcome reported was number of ulcers healed, and these data were uncertain (very low-certainty evidence).