Metformin in peritoneal dialysis: a pilot experience.

OBJECTIVE: In a number of patients, the antidiabetic drug metformin has been associated with lactic acidosis. Despite the fact that diabetes mellitus is the most common cause of end-stage renal disease (ESRD) and that peritoneal dialysis (PD) is an expanding modality of treatment, little is known about optimal treatment strategies in the large group of PD patients with diabetes. In patients with ESRD, the use of metformin has been limited because of the perceived risk of lactic acidosis or severe hypoglycemia. However, metformin use is likely to be beneficial, and PD might itself be a safeguard against the alleged complications. METHODS: Our study involved 35 patients with insulin-dependent type 2 diabetes [median age: 54 years; interquartile range (IQR): 47-59 years] on automated PD (APD) therapy. Patients with additional risk factors for lactic acidosis were excluded. Metformin was introduced at a daily dose in the range 0.5 - 1.0 g. All patients were monitored for glycemic control by blood sugar levels and HbA1c. Plasma lactic acid levels were measured weekly for 4 weeks and then monthly to the end of the study. Plasma and effluent metformin and plasma lactate levels were measured simultaneously. RESULTS: In this cohort, the median duration of diabetes was 18 years (IQR: 14 - 21 years), median time on PD was 31 months (IQR: 27 - 36 months), and median HbA1c was 6.8% (IQR: 5.9% - 6.9%). At metformin introduction and at the end of the study, the median anion gap was 11 mmol/L (IQR: 9 - 16 mmol/L) and 12 mmol/L (IQR: 9 - 16 mmol/L; p > 0.05) respectively, median pH was 7.33 (IQR: 7.32 - 7.36) and 7.34 (IQR: 7.32 - 7.36, p > 0.05) respectively, and mean metformin concentration in plasma and peritoneal fluid was 2.57 ± 1.49 mg/L and 2.83 ± 1.7 mg/L respectively. In the group overall, mean lactate was 1.39 ± 0.61 mmol/L, and hyperlactemia (>2 mmol/L to 5 mmol/L) was found in 4 of 525 plasma samples (0.76%), but the patients presented no symptoms. None of the patients registered a plasma lactate level above 5 mmol/L. We observed no correlation between plasma metformin and plasma lactate (r = 0.27). CONCLUSIONS: Metformin may be used with caution in APD patients with insulin-dependent type 2 diabetes. Although our study demonstrated the feasibility of metformin use in APD, it was not large enough to demonstrate safety; a large-scale study is needed.

Tunneled catheter-antibiotic lock therapy for prevention of dialysis catheter-related infections: a single center experience.

Tunneled cuffed central vein catheters (TCC) are widely used for delivering hemodialysis (HD). Infection is the principal cause of morbidity and mortality associated with central vein catheters in patients on HD. The optimal strategy to combat TCC infection is controversial. This prospective study assesses the efficacy of antibiotic-lock therapy using vancomycin and gentamycin in preventing catheter-related blood stream bacterial infection in patients on HD. A total of 86 TCC in 69 HD patients were enrolled at the time of catheter insertion for delivering HD. Patients were randomized into two groups: Group I (36 patients-39 insertions) included TCC with antibiotic-lock therapy and Group II (33 patients-47 insertions) with routine TCC management. Infection-free catheter survival of both groups was evaluated and compared at the end of the 18-month study period. A total of 72 TCC infections were detected with an incidence rate of 6.78 infections/1000 dialysis sessions. The rate of infection was significantly lower in Group I (4.39/1000 dialysis sessions) compared to Group II (11.69/1000 dialysis sessions), p<0.001. The bacteremia rate, as well as rate of clinical sepsis were also significantly lower in Group I than in Group II (p<0.001). There was no statistically significant difference in the rate of access site infection in the two groups (p>0.05). Our study suggests that antibiotic-lock therapy using a combination of vancomycin and gentamycin is useful in preventing catheter-related blood stream infection in patients on HD.