Impact of Hypomagnesemia at the time of Hospital Admission on the Outcomes of Patients with Critical Care Illness

Abstract

Background: Magnesium, often referred to as the ‘forgotten electrolyte,’ is the fourth most abundant mineral in the body and plays a critical role in cardiovascular, neuromuscular, and renal functions, as well as in maintaining immune system integrity. Magnesium deficiency can complicate patient management in the intensive care unit (ICU).

Objectives: To investigate the impact of hypomagnesemia at the time of admission on patient outcomes in the intensive care units (ICUs); and to examine the correlation between hypomagnesemia and the APACHE II scoring system in predicting outcomes among critically ill patients admitted to the ICU.

Methods: This was a hospital based, prospective observational study (descriptive and non-interventional study) conducted among critically ill patients admitted to the ICU under the Department of General Medicine at the JSS Medical College, Mysuru, Karnataka, India between July 2023 and December 2024.

Results: Hypomagnesemia was observed in 31.3% of patients. It was significantly associated with vomiting (P < 0.001), diabetes mellitus (P = 0.002), chronic kidney disease (P < 0.001), chronic liver disease (P = 0.007), alcohol intake (P = 0.001), and pallor (P = 0.016). Laboratory findings revealed lower haemoglobin, elevated ESR, direct bilirubin, alkaline phosphatase (ALP), blood urea, and procalcitonin levels in the hypomagnesemia group (P < 0.05). Electrolyte imbalances (lower sodium, potassium, and chloride) and impaired oxygenation parameters were also noted. Hypomagnesemia correlated negatively with APACHE II scores (rp = -0.484), ICU stay (rp = -0.442), and ventilator days (rp = -0.416). APACHE II scores were superior in predicting mechanical ventilation (AUC = 0.839) and mortality (AUC = 0.843) compared to magnesium levels.

Conclusion: Hypomagnesemia is prevalent in critically ill patients and is associated with worse clinical and biochemical profiles, prolonged ICU stays, and greater ventilator dependency. Routine magnesium monitoring and targeted management strategies may improve patient outcomes.