Urgent-Start Peritoneal Dialysis in Metformin-Associated Lactic Acidosis: A Critical Alternative when Immediate Hemodialysis Is Unavailable

Introduction: Intermittent hemodialysis (IHD) is a preferable renal replacement therapy (RRT) option in metformin-associated lactic acidosis (MALA) due to rapid correct metabolic acidosis. However, IHD might not be started immediately. Immediate urgent-start peritoneal dialysis (iUSPD) is used as a life-saving dialysis option and then followed by IHD. The outcomes of iUSPD were compared with other extracorporeal dialysis in MALA. Methods: In two tertiary hospitals in Thailand, the outcomes of patients with MALA who had received three different RRT modalities (iUSPD followed by IHD, IHD, and continuous renal replacement therapy [CRRT]) from January 2015 to December 2019 were compared. The primary outcome was 30-day mortality. The secondary outcomes were door-to-dialysis time and 90-day RRT dependence. Results: A total of 180 MALA cases that required dialysis were included (20 iUSPD, 120 IHD, and 40 CRRT). Their mean age was 64 years. Most of the patients had severe metabolic acidosis (mean pH 6.91, HCO₃ 6 mmol/L, and anion gap 40 mmol/L) and were critically ill. The 30-day mortality was 30% in iUSPD, 9.2% in IHD, and 32.5% in CRRT (p = 0.001). The mortality risk in the iUSPD group was not significantly different from those of the IHD and CRRT groups (adjusted HR 2.5, 95% CI: 0.65–9.6, and adjusted HR 0.75, 95% CI: 0.2–2.78, respectively). All dialysis modalities had comparable 90-day dialysis dependence. iUSPD exhibited the shortest door-to-dialysis time. Conclusion: In MALA, iUSPD followed by IHD might be a viable RRT option to save patient lives if no other dialysis options are available.