Kidney replacement therapy and mortality in metformin-associated lactic acidosis with acute kidney injury (2015–2021): a multi-year cohort study

Metformin-associated lactic acidosis (MALA) is a life-threatening complication. Treatment of MALA includes supportive care and dialysis. However, the role of kidney replacement therapy (KRT) in MALA is controversial, this study aimed to compare patient and kidney outcomes between MALA-acute kidney injury (AKI) patients receiving KRT (KRT group) vs. supportive care (supportive care group). A cohort study was conducted on 143 adult patients with MALA-AKI from 1 January 2015 to 31 December 2021. The primary outcome was the patient mortality rate and predictive factors of mortality, while the secondary outcomes were kidney survival. The overall mortality rate in our MALA-AKI cohort was 20.3% (29 of 143 patients). The KRT group had a lower mortality rate compared with the supportive care group (16% vs. 28.6%, <i>P</i> = 0.006). Among patients who received dialysis, hemodialysis (HD) was associated with a lower mortality rate compared with acute peritoneal dialysis (APD) (8.9% vs. 30.8%, <i>P</i> = 0.044). Patients who received late KRT (≥6 h) had a trend toward higher mortality compared with those who received early KRT (<6 h). Independent predictors of mortality were oliguria (HR 8.59, <i>P</i> = 0.002), prolonged prothrombin time (HR 1.20, <i>P</i> = 0.001) and higher Sequential Organ Failure Assessment (SOFA) scores (HR 1.26, <i>P</i> = 0.006). MALA-AKI was associated with high mortality, and KRT reduced mortality rate when compared with supportive care. HD was the most effective treatment in MALA-AKI, early KRT initiation (<6 h) showed a trend toward lower mortality and oliguria, prolonged prothrombin time, and higher SOFA scores were identified as prognostic markers.