Israel Medical Association Journal

Background: Concerns about metformin-associated lactic acidosis (MALA) prohibit the use of metformin in a large subset of diabetic patients, mostly in patients with chronic kidney disease. Increasing evidence suggests that the current safety regulations may be overly restrictive.

Objectives: To examine the association between chronic metformin treatment and lactate level in acute illness on the first day of admission to an internal medicine ward.

Methods: We compared diabetic and non-diabetic hospitalized patients treated or not treated with metformin in different sets of kidney function.

Results: A total of 140 patients participated in the study, 54 diabetic patients on chronic metformin treatment, 33 diabetic patients without metformin and 53 patients with no diabetes. Most participants were admitted for conditions that prohibit metformin use, such as heart failure, hypoxia and sepsis. Average lactate level was significantly higher in the diabetes + metformin group compared to the diabetes non-metformin group. Metformin treatment was not associated with higher than normal lactate level (hyperlactatemia) or low pH. No patient was hospitalized for lactic acidosis as the main diagnosis.

Conclusions: Chronic metformin treatment mildly increases lactate level, but does not induce hyperlactatemia or lactic acidosis in acute illness on the first day of admission to an internal medicine ward. These data support the expansion of metformin use.

Background: Serum lactate dehydrogenase (LDH) is elevated in various diseases. 

Objectives: To analyze serum LDH as a distinguishing clinical biomarker and as a predictor of in-hospital outcome in admitted medical patients.

Methods: We analyzed a cohort of all 158 patients with very high isolated LDH (LDH ≥ 800 IU/ml – without concomitant elevations of alanine aminotransferase and aspartate aminotransferase) – admitted to our internal medicine department during a 3 year period. Epidemiologic and clinical data, as well as the final diagnosis and outcome were recorded and compared with those of a cohort of all 188 consecutive control patients.

Results: Very high isolated LDH was a distinguishing biomarker for the presence of cancer (27% vs. 4% in the LDH group and controls respectively, P < 0.0001), liver metastases (14% vs. 3%, P < 0.0001), hematologic malignancies (5% vs. 0%, P = 0.00019), and infection (57% vs. 28%, P < 0.0001). Very high isolated LDH was a marker for a severe prognosis, associated with more admission days (9.3 vs. 4.1, P < 0.0001), significantly more in-hospital major complications, and a high mortality rate (26.6% vs. 4.3%, P < 0.0001). Finally, very high isolated LDH was found in a multivariate regression analysis to be an independent predictor of mortality.

Conclusions: The presence of very high isolated LDH warrants thorough investigation for the presence of severe underlying disease, mostly metastatic cancer, hematologic malignancies and infection. Moreover, it is a marker for major in-hospital complications and is an independent predictor of mortality in admitted medical patients.