title: Outcome of severe lactic acidosis associated with metformin accumulation.
abstract: BACKGROUND
  Metformin associated lactic acidosis (MALA) may complicate metformin therapy, particularly if metformin accumulates due to renal dysfunction. Profound lactic acidosis (LA) generally predicts poor outcome. We aimed to determine if MALA differs in outcome from LA of other origin (LAOO).
  
  
  METHODS
  We conducted a retrospective analysis of all patients admitted with LA to our medical ICU of a tertiary referral center during a 5-year period. MALA patients and LAOO patients were compared with respect to parameters of acid-base balance, serum creatinine, hospital outcome, Simplified Acute Physiology Score II (SAPS II) and Sequential Organ Failure Assessment (SOFA) score, using Pearson's Chi-square or the Mann-Whitney U-test.
  
  
  RESULTS
  Of 197 patients admitted with LA, 10 had been diagnosed with MALA. With MALA, median arterial blood pH was significantly lower (6.78 [range 6.5 to 6.94]) and serum lactate significantly higher (18.7 ± 5.3 mmol/L) than with LAOO (pH 7.20 [range 6.46 to 7.35], mean serum lactate 11.2 ± 6.1 mmol/L). Overall mortality, however, was comparable (MALA 50%, LAOO 74%). Furthermore, survival of patients with arterial blood pH < 7.00 (N = 41) was significantly better (50% vs. 0%) if MALA (N = 10) was the underlying condition compared to LAOO (N = 31).
  
  
  CONCLUSIONS
  Compared to similarly severe lactic acidosis of other origin, the prognosis of MALA is significantly better. MALA should be considered in metformin-treated patients presenting with lactic acidosis.
authors.affiliation: Department of Cardiology, Pneumology and Intensive Care Medicine, Ernst Moritz Arndt University, 17475 Greifswald, Germany. sigrun.friesecke@uni-greifswald.de
authors.forename: Sigrun
authors.initials: S
authors.lastname: Friesecke
authors.forename: Peter
authors.initials: P
authors.lastname: Abel
authors.forename: Markus
authors.initials: M
authors.lastname: Roser
authors.forename: Stephan B
authors.initials: SB
authors.lastname: Felix
authors.forename: Soeren
authors.initials: S
authors.lastname: Runge
mesh_terms: D000140:Acidosis, Lactic / Q000097:blood / Q000139:chemically induced / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008687:Metformin / Q000009:adverse effects* / Q000097:blood; D008875:Middle Aged; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D008687:Metformin