Abstract
Aims The aim of this case report is to specify the frequency and mortality of Metformin-Associated
Lactic Acidosis (MALA) in emergency medicine, as the diagnosis seems to occur more
often than estimated.
Methods To identify the subjects, we developed screening criteria for MALA. We measured the
serum metformin concentration to confirm the diagnosis in all patients fulfilling
these criteria. Retrospectively the patients were grouped according to individual
risk (according to a defined risk score) and the application of renal replacement
therapy.
Results From 2013 until 2018 we were able to identify 11 MALA patients revealing a frequency
of 1:4,000 emergency patients. Six patients survived and five died in the follow-up.
All three patients in the high-risk group died although all of them received renal
replacement therapy. In the low-risk group (three patients, one with renal replacement
therapy), all patients survived, while in the intermediate-risk group (five patients,
one with renal replacement therapy) three patients survived and two died. Additional
severe comorbidities also contributed to mortality.
Conclusions Every patient matching the screening criteria of acute renal failure, lactic acidosis
and continued intake of metformin can be considered a potential MALA case. A risk
score assessment which includes severe comorbidities may help to identify high-risk
individuals and should be evaluated in larger studies.To prevent MALA, patients should
be trained to immediately interrupt their own metformin use when showing signs of
volume depletion. Physicians should be aware of the additional risk factors such as
co-medication with diuretics, ACE (angiotensin converting enzyme) ACE inhibitors and
NSAIDs (non steroidal anti inflammatory drugs).
Key words
metformin - lactic acidosis - renal insufficiency - type 2 diabetes mellitus
