Correlation of Serum Magnesium Levels with Clinical Outcome: A Prospective Observational Study in Critically Ill Patients Admitted to a Tertiary Care ICU in India

Background: We studied the incidence of magnesium (Mg) disturbances in patients admitted to a multidisciplinary intensive care unit (ICU) and correlated serum magnesium levels with clinical outcomes.Materials and methods:The study was conducted on 280 critically ill patients aged above 18 years and admitted to the ICU. Serum magnesium levels at admission were correlated with mortality, need for and duration of mechanical ventilation, duration of ICU stay, presence of comorbid conditions, and electrolyte disturbances. Result:There was a high incidence of Mg disturbances at admission among patients admitted to the ICU. The incidence of hypomagnesemia and hypermagnesemia was 40.9 and 13.9% respectively. The mean Mg level among patients who expired was 1.55 +/- 0.68 mg/dL, and the association with outcome was found to be statistically significant (p = 0.001). Hypomagnesemia (HypoMg) was associated with significantly higher mortality (51.3%) as compared to normomagnesemia (NormoMg) (29.3%) and hypermagnesemia (HyperMg) (23.1%) (HypoMg vs NormoMg, HypoMg vs HyperMg,p = 0.001, 0.002 respectively). The need for mechanical ventilation was significantly higher in hypomagnesemic as compared to hypermagnesemia patients (p = 0.012). The association of baseline APACHE II and SOFA scores with serum Mg levels was statistically significant (p = 0.001 and 0.002 respectively). The incidence of gastrointestinal disorders was significantly higher among hypomagnesemia patients (HypoMg vs NormoMg,p= 0.023), while chronic kidney disease was significantly higher in hypermagnesemic patients (HypoMg vs HyperMg,p = 0.0009, NormoMg vs HyperMg,p = 0.0004). On comparing the incidence of electrolyte disorders between HypoMg, NormoMg, and HyperMg groups, it was found that hypokalemia and hypocalcemia (p = 0.0003 and 0.039 respectively) were associated with hypomagnesemia and hyperkalemia and hypercalcemia (p = 0.001 and 0.005 respectively) were associated with hypermagnesemia.Conclusion: Our study highlights the role of Mg monitoring in critically ill patients admitted to the ICU and its value for a favorable outcome. We found that hypomagnesemia was significantly associated with adverse outcomes and higher mortality in critically ill patients. Intensivists should maintain a high index of suspicion for Mg disturbances and evaluate patients appropriately.