The Phantom of Metformin-Induced Lactic Acidosis in End-Stage Renal Disease Patients: Time to Reconsider with Peritoneal Dialysis Treatment.

♦ OBJECTIVE: Metformin continues to be the safest and most widely used antidiabetic drug. In spite of its well-known benefits; metformin use in end-stage renal disease (ESRD) patients is still restricted. Little has been reported about the effect of peritoneal dialysis (PD) on metformin clearance and the phantom of lactic acidosis deprives ESRD patients from metformin therapeutic advantages. Peritoneal dialysis is probably a safeguard against lactic acidosis, and it is likely that using this drug would be feasible in this group of patients. ♦ MATERIAL AND METHODS: The study was conducted on 83 PD patients with type 2 diabetes mellitus. All patients were on automated PD (APD). Metformin was administered in a dose of 500 - 1,000 mg daily. Patients were monitored for glycemic control. Plasma lactic acid and plasma metformin levels were monitored on a scheduled basis. Peritoneal fluid metformin levels were measured. In addition, the relation between plasma metformin and plasma lactate was studied. ♦ RESULTS: Mean fasting blood sugar (FBS) was 10.9 ± 0.5 and 7.8 ± 0.7, and mean hemoglobin A1-C (HgA1C) was 8.2 ± 0.8 and 6.4 ± 1.1 at the beginning and end of the study, respectively (p < 0.001). The mean body mass index (BMI) was 29.1 ± 4.1 and 27.3 ± 4.5 at the beginning and at the end of the study, respectively (p < 0.001). The overall mean plasma lactate level across all blood samples was 1.44 ± 0.6. Plasma levels between 2 and 3 mmol/L were found in 11.8% and levels of 3 - 3.6 mmol/L in 2.4% plasma samples. Hyperlactemia (level > 2 and ≤ 5 mmol/L) was not associated with overt acidemia. None of our patients had lactic acidosis (levels > 5 mmol/L). Age ≥ 60 was a predictor for hyperlactemia. No relationship was found between plasma metformin and lactate levels. ♦ CONCLUSION: Metformin may be used with caution in a particular group of ESRD patients who are on APD. Metformin allows better diabetic control with significant reduction of BMI. Information on the relationship between metformin and plasma lactate levels is lacking. Peritoneal dialysis appears to be a safeguard against the development of lactic acidosis in this group of patients.