The importance of early haemodiafiltration in the treatment of lactic acidosis associated with the administration of metformin

Metformin is a drug widely used in type 2 diabetic patients. Metformin-associated lactic acidosis (MALA) in diabetic patients is rare but can be serious. However, the relationship between metformin and lactic acidosis is under debate. We present seven cases of patients with MALA who came to our centre over a period of one year and who were treated early with haemodiafiltration. There are some risk factors that appear to predispose patients to this pathology, such as: acute renal failure, situations of hypoxemia and sepsis, cardiac or respiratory failure, previous history of lactic acidosis, liver disease and dehydration. As such, the use of metformin is discouraged in patients with GFR below 30 ml/min/1.73 m(2). All patients in our study were treated early with haemodiafiltration. The mortality in our study was 16.6%. We believe that MALA is a serious condition that requires prompt diagnosis and early treatment. Renal replacement therapy is not the solution for all patients, but can improve prognosis in more severe cases if started early. We should limit the use of metformin in diabetic patients with impaired renal function, although there is still controversy in the medical literature.