Metformin ointment may relieve hypertrophic and keloid scars

Abstract

Various factors are involved in keloid and hypertrophic scar formation. Keloid and hypertrophic scars differ in incidence, location, histology and treatment. Previous research showed that metformin has antioxidant and anti-inflammatory properties, antiageing and antitumour, and cardioprotective and neuroprotective effects. 1 Here we conducted a clinical trial study to investigate the metformin topical ointment for treating hypertrophic scar and keloid and compared it with the placebo. MATERIALS AND METHODSA randomized, blinded, clinical trial study was conducted on hypertrophic scar and keloid patients between 2021 and 2022 in 15 Khordad Hospital (Tehran, Iran). Exclusion criteria were: diabetes, lactation and pregnancy, bleeding and discharge in the scar tissue site, chemotherapy, allergy history to metformin or placebo and history of scar treatment in the last 2 months. All patients were randomly assigned to receive metformin or placebo ointments. Metformin hydrochloride powder dissolved in water and dispersed in the base ointment (lanolin, fatty acids, cholesterol, wax) at a concentration of 0.5% (w/v). Placebo ointment was prepared similarly without metformin hydrochloride powder. The patients used the topical metformin ointment 0.5% (w/v) and placebo twice a day for 3 months and we used the Vancouver Scar Scale (VSS) (Table 1) before and during the study for assessment of the scars which have four variables: Vascularity (normal = 0, pink = 1, red = 2 and purple = 3), pigmentation (normal = 0, hypopigmentation = 1 and hyperpigmentation = 2), pliability (normal = 0, supple = 1, yielding = 2, firm = 3, ropes = 4 and contracture = 5) and height (flat = 0, <2 mm = 1, 2-5 mm = 2 and >5 mm = 3). Furthermore, all patients were followed for 6 months to evaluate the effects of treatment. Written consent was obtained from all patients in this clinical trial study, and a physician evaluated patients' scars.