Efficacy of topical insulin in wound healing: A preliminary systematic review and meta-analysis of randomized controlled trials.

Topical insulin has been shown to promote wound healing in various studies. Considering the absence of a systematic review and quantitative synthesis on the same, the present study was carried out. Using an appropriate search strategy, electronic databases were searched for randomized controlled trials that have compared topical application of insulin in wounds with normal saline. Standardize mean differences were calculated for the following outcome measures: healing rate of ulcers/wound, percent granulation tissue growth, microvessel density, time to heal, wound area and ulcer severity score. Cochrane's risk of bias tool was used for each of the studies and RevMan 5.3 software was used to generate the pooled estimates and Forest plots. The quality of evidence was assessed by the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) working group approach. A total of 8 studies were found eligible to be included in this review and 7 for the meta-analysis. The pooled estimates were as follows: healing rate-0.04 [-1.38, 1.46]; percent granulation tissue-10.99 [-10.07, 32.06], microvessel density-3.01 [-1.67, 7.69] and wound area--6.59 [-9.7, -3.48]. There was only one study for each of the following outcome measures: time to heal and ulcer severity score. Hence, pooling of the results was not attempted for these outcome measures. The studies conducted in this field were preliminary and it was difficult to draw any conclusion regarding the use of insulin topically for wound healing.