Serum Magnesium and Short-Term Outcomes in Critically Ill Adults: Associations with Mechanical Ventilation, ICU Mortality, and Length of Stay

Abstract

Serum magnesium disturbances are common in critical illness, but their relationships with clinically important intensive care unit (ICU) outcomes remain inconsistent. This prospective observational cohort study evaluated associations of serum magnesium with mechanical ventilation, ICU mortality, ICU length of stay, and ventilation duration in critically ill adults. Ninety-nine patients admitted to the ICU of Dr. Wahidin Sudirohusodo General Hospital, Makassar, Indonesia, were enrolled and followed throughout their ICU stay. Serum magnesium obtained during the initial ICU assessment was analyzed primarily as a continuous variable. Multivariable logistic regression adjusted for age and APACHE II score was used for mechanical ventilation and ICU mortality, while ICU length of stay was analyzed using negative binomial regression. Median serum magnesium was 1.94 mg/dL (Q1–Q3, 1.65–2.11); 76.8% of patients required mechanical ventilation and 33.3% died in the ICU. Serum magnesium was not independently associated with mechanical ventilation (aOR 1.86, 95% CI 0.52–6.70; p=0.340) or ICU mortality (aOR 2.11, 95% CI 0.60–7.36; p=0.243). Higher magnesium was associated with longer ICU stay (IRR 1.60, 95% CI 1.06–2.41; p=0.025), although the overall model was not significant (p=0.123). Magnesium also correlated positively with ventilation duration among ventilated patients (ρ=0.361; p=0.001). Serum magnesium may therefore reflect aspects of critical illness course rather than independently predict mechanical ventilation or ICU death.