Topical Insulin versus Topical Phenytoin in Healing of Diabetic Foot Ulcers: A Prospective Observational Study

Introduction: Insulin, when applied as a local dressing, stimulates the growth and development of keratinocytes, endothelial cells, and fibroblasts, which aid in proliferation and tissue healing. Phenytoin, when used as a local dressing, has been extensively studied due to its positive effects on ulcer healing. These effects include increased fibroblast proliferation, collagen deposition, neovascularisation, enhanced granulation tissue formation, decreased collagenase activity, and reduced bacterial contamination. Aim: To compare the efficacy of topical insulin with topical phenytoin in Diabetic Foot Ulcers (DFUs). Materials and Methods: This prospective observational study was conducted in the Department of Surgery, at Mamata Medical College, Khammam, Telangana, India from August 2022 to July 2024. It included 64 cases of DFU (32 in each group), randomised by the envelope method. Group A: Topical insulin dressing (0.5 mL insulin with 5 mL normal saline). Group B: Topical phenytoin dressing (100 mg in 5 mL normal saline). Outcomes were measured in terms of wound size and percentage of wound contraction on days 7, 14, and 21, compared to Day 1 of the study. An unpaired t-test was used for the analysis of continuous data, while Pearson’s Chi-square test was used for the analysis of categorical data. Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) version 24.0. Results: The mean age of subjects in Group A was 49.72±12.28 years, and in Group B, it was 52.28±12.79 years. The male-tofemale ratio was 2.5:1 in Group A and 1.285:1 in Group B. The mean ulcer size for Group A on Day 1 was 17.88±3.148 cm², and for Group B, it was 17.3±3.47 cm², with a p-value > 0.05. The mean reduction in ulcer size for the topical insulin group was 2.6 cm², while for the topical phenytoin group, it was 6.33 cm² (p-value <0.0001). The percentage of reduction in mean ulcer size was greater in the topical phenytoin group (36.41%) compared to the topical insulin group (14.5%), with a p-value < 0.0001. The mean duration for complete epithelialisation of the ulcer, or when the ulcer bed was ready for split skin grafting, was 26.75 days in the topical insulin group and 20.8 days in the topical phenytoin group (p-value<0.0001). A total of 27 (84.375%) and 30 (93.75%) cases in the topical insulin group and the topical phenytoin group, respectively, underwent split skin grafting. Five patients in the topical insulin group and two patients in the topical phenytoin group achieved complete healing of the ulcer by secondary intention. Conclusion: Topical phenytoin was found to be relatively more effective than topical insulin in enhancing wound healing in terms of percentage reduction in ulcer size and duration for complete epithelialisation.