Localised insulin administration for wound healing in non-diabetic adults: A systematic review and meta-analysis of randomised controlled trials

Insulin has the potential to restore damaged skin and due to its affordability and global availability, it is an agent of interest when it comes to pioneering new remedies to accelerate wound healing. The aim of this study was to explore the efficacy and safety of localised insulin administration on wound healing in non-diabetic adults. Studies were systematically searched, using the electronic databases Embase, Ovid MEDLINE and PubMed, screened, and extracted by two independent reviewers. A total of seven randomised controlled trials that met the inclusion criteria were analysed. Risk of bias was assessed using the Revised Cochrane Risk-of-Bias Tool for Randomised Trials and a meta-analysis was performed. The primary outcome, which explored rate of wound healing (mm(2)/day), concluded that there was an overall significant mean improvement in the insulin treated group (IV = 11.84; 95% CI: 0.64-23.04; p = 0.04; I-2 = 97%) compared to the control group. Secondary outcomes concluded that there is no statistical difference between the healing time (days) of the wound (IV = -5.40; 95% CI: -11.28 to 0.48; p = 0.07; I-2 = 89%); there is a significant reduction in wound area in the insulin group; no adverse events were noted with the administration of localised insulin; quality of life improves drastically as the wound heals, irrespective of insulin. We conclude that although the study showed an improved wound healing rate, other parameters were not statistically significant. Therefore, larger prospective studies are warranted to fully explore the effects of insulin on different wounds, where an appropriate insulin regime can be developed for clinical practice.