Effects of topical insulin on wound healing: a meta-analysis of animal and clinical studies

Various researches have reported that the application of topical insulin improves wound healing. Considering the lack of a quantitative comprehensive research on this matter, we conducted a meta-analysis of clinical research and experimental animal studies. Prospective and randomized controlled trials of PubMed, Embase, and Cochrane Library were conducted using appropriate search strategies to compare the effectiveness of topical application of saline and insulin on wounds. The standardized mean difference was calculated as follows: wound healing time, wound healing rate, wound area, and the percentage of wound contraction. Each study used the Cochrane risk-of-bias tool and RevMan 5.3 software to create aggregated assessments and forest plots. The quality of evidence was evaluated in accordance with the methods of the Grading of Recommendations, Assessment, Development and Evaluation working group. Four clinical and nine animal studies eligible for inclusion were included in the meta-analysis. The assessments for clinical studies were as follows: wound healing time, -2.48 [-3.44, -1.51] and wound healing rate, 22.23 [18.17, 26.28]. Meanwhile, for animal studies, the following assessments were noted: wound healing time, -1.27 [-1.75, -0.79]; wound contraction rate, 15.91 [13.88, 17.95]; and wound area, -19.3 [-21.16, -17.44]. For the measurement of the following results, only one animal study was performed, pericyte recruitment of microvessels. Based on the analysis, it can be preliminarily judged that application of topical insulin can aid wound healing.