Metformin-associated hyperlactacidaemia acidosis: Diagnosis rate in standard clinical practice and its relationship...

Observational study on the difference between the number of cases of acidosis with hyperlactacidaemia suspected of being caused by metformin diagnosed in standard clinical practice and the incidence of this condition according to the datasheet. The study also explored the relationship between renal function and metformin-associated hyperlactacidaemia acidosis.

We identified cases of acidosis between 2013 and 2014 by analysing the minimum basic data set and laboratory requests. We selected patients who presented venous lactate levels >2.7 mmol/L at the time they were treated and for whom the use of outpatient metformin was confirmed. The causal relationship with metformin was independently evaluated by several researchers. The incident cases were calculated based on the number of patients who had been dispensed a drug containing metformin during the same period in the study area.

We identified 476 cases of acidosis. Metformin was suspected of causing the condition of acidosis with hyperlactacidaemia in 20 of these cases, which represents an incidence rate of 6.57/10,000 patients. Eighty-five percent of the cases presented acute renal failure.

The apparent incidence of acidosis with hyperlactacidaemia in patients treated with metformin is greater than that established in the datasheet (<1/10,000). The onset of metformin-associated hyperlactacidaemia acidosis is related to acute renal impairment.