Transplantation and Diabetes (Transdiab): A Pilot Randomised Controlled Trial of Metformin in pre-diabetes after kidney transplantation

Diabetes occurs in up to 50% of patients after kidney transplantation and is associated with increased mortality and transplant failure. We propose a pilot randomised controlled trial of Metformin compared with standard of care in patients who develop impaired glucose tolerance or elevated fasting plasma glucose early after kidney transplantation aiming to determine safety and tolerability of Metformin, the incidence of development of diabetes, and the effect of Metformin on body weight at 12 months after transplantation. All consenting patients transplanted at Auckland City Hospital who do not have pre-existing diabetes will be enrolled in the study. Patients will undergo an oral glucose tolerance test when clinically stable at 4 – 6 weeks after kidney transplantation. Patients who have an elevated fasting glucose, or impaired glucose tolerance will be randomised to Metformin in addition to standard of care advice regarding diet and exercise, or standard advice alone. Follow up will be for 12 months. Metformin has been shown to prevent development of diabetes in the general population. Additionally it does not cause hypoglycaemia and has beneficial effects on all cause and cardiac mortality. Demonstration that Metformin is well tolerated in the group at highest risk of developing diabetes and assessment of its effect on serum glucose will advise on numbers required to investigate the effect of this drug in preventing diabetes in a larger study. As outcomes of all consenting patients will be followed, information regarding the incidence of diabetes and glucose intolerance in our population over a year will also be generated.