Impact of acute kidney injury on metformin-associated lactic acidosis

Metformin has been shown to reduce diabetic complications in overweight patients, and is increasingly used to treat this condition. However, this agent is associated with a rare but serious risk of lactic acidosis. From January 2004 to November 2008, 11 cases of metformin-associated lactic acidosis were seen at a medical center in Taiwan. The patients' records were retrospectively reviewed with respect to clinical presentation, biochemical data, therapeutic strategies, and outcomes. Ten out of 11 patients with acute kidney injury were enrolled in this study. From their pre-existing states, these patients would have been considered at low risk of developing lactic acidosis. However, all of them had acute intercurrent conditions that might compromise renal function. Among them, six patients were ventilated and five patients had severe hypotension with vasoactive support. Nine patients received renal replacement therapy to clear the acidosis and treat the renal failure. All but one of our patients survived. Recovery of renal function was the general rule in survivors. Metformin-associated lactic acidosis is commonly accompanied with acute kidney injury. In spite of the severity of their illness, the outcome is favorable with intensive support of the cardiovascular, respiratory, and renal systems.