Metformin with insulin does not improve the glycaemic control of overweight/obese adolescents with type 1 diabetes

Design: Placebo-controlled randomised controlled trial. Allocation: Via computer generated sequence. Blinding: Double-blind. Setting: 26 paediatric endocrinology clinics in the Type 1 Diabetes Exchange Clinic Network between 2013 and 2014. Patients: 140 adolescents aged between 12.1 and 19.6 years (mean (SD) 15.3 (1.7)) with type 1 diabetes for >1 year and a body mass index >85th centile for age, total daily insulin dose >0.8 units/kg and three times daily self-monitoring of blood glucose. Intervention : 2000 mg daily dose metformin compared with placebo. Outcomes : Primary outcome: change in haemoglobin A1c (HbA1c) from baseline to 26 weeks. Prespecified secondary outcomes: total daily dose (TDD) insulin per kg body weight, total basal insulin per kg body weight, anthropometry, blood pressure, metabolic profile. Follow-up period …