Retrospective Analysis of Serum Magnesium and Its Association With Lactate in Septic ICU Patients

Introduction: Elevated lactate levels are associated with increased mortality. Magnesium serves as a cofactor in the conversion of pyruvate to acetyl coenzyme A in aerobic metabolism. In the absence of adequate magnesium, cellular metabolism shifts toward anaerobic pathways, leading lactate dehydrogenase to convert pyruvate into lactate. The goal of this study was to retrospectively evaluate the association between serum magnesium and lactate levels in patients with sepsis.


Methods: This IRB approved study included septic ICU patients from July 1, 2022, to June 30, 2024, who were 19 years and older with sepsis and had magnesium and lactate levels monitored on days 1-5.

Discrete categorical variables were analyzed with chi-square or Fisher’s exact test. Continuous variables were analyzed using student t-test. Multivariable regressions were used to determine risk factors for the primary endpoint of all-cause in-hospital mortality. A significant difference in any variable was determined based on p < 0.05. Results are presented as mean ± SD or percentages.


Results: 75 patients met inclusion criteria, with 52% male, 71% Caucasian, and 11% African American. Twenty-one (28%) of patients expired. Mean (± SD) age was 62.5 ± 15.9 years for patients who survived and 67.8 ± 12.0 years for non-survivors. Non-survivors had higher SOFA scores 11 ± 4 compared to survivors 8.5 ± 4, p=0.018. 56% of patients had concomitant diseases like CKD. No differences in Mg on day 1, 2, or 3 between those that survived and those that died. There was no correlation between Mg and lactic acid on day 1, 2, or 3. There was a significant correlation (p=0.002) between day 1 lactic acid and patients undergoing CRRT but not receiving mechanical ventilation. No significant differences in Mg supplementation for survivors compared to non-survivors.


Conclusions: In this retrospective study of patients admitted to the ICU with sepsis there was no significant association between serum magnesium levels and lactate during the first three days of admission. Additionally, magnesium supplementation did not impact mortality outcomes. Our findings continue to suggest that lactate remains a valuable prognostic marker in sepsis, and magnesium levels may not play a direct role in influencing lactate metabolism or patient outcomes in this population.