Admission Serum Magnesium Levels Predict the Risk of Acute Respiratory Failure Requiring Mechanical Ventilation in Hospitalized Patients

PURPOSE: The association between admission serum magnesium (Mg) levels and risk of acute respiratory failure (ARF) requiring mechanical ventilation in hospitalized patients is limited. The aim of this study was to assess the risk of developing ARF in all hospitalized patients with various admission Mg levels. METHODS: This is a single-center retrospective study conducted at a tertiary referral hospital. All hospitalized adult patients who had admission Mg available from January to December 2013 were analyzed in this study. Admission Mg was categorized based on its distribution into six groups (less than 1.5, 1.5 to 1.7, 1.7 to 1.9, 1.9 to 2.1, 2.1 to 2.3, and greater than 2.3 mg/dL). The primary outcome was in-hospital ARF requiring mechanical ventilation occurring after hospital admission. Logistic regression analysis was performed to obtain the odds ratio of ARF of various admission Mg levels using Mg of 1.7 to 1.9 mg/dL as the reference group. RESULTS: Of 9,780 patients enrolled, ARF occurred in 619 patients (6.3%). The lowest incidence of ARF was when serum Mg within 1.7-1.9 mg/dL. A U-shaped curve emerged demonstrating higher incidences of ARF associated with both hypoMg (<1.7) and hyperMg (>1.9). After adjusting for potential confounders, both hypoMg (<1.5 mg/dL) and hyperMg (>2.3 mg/dL) were associated with an increased risk of developing ARF requiring mechanical ventilation with odds ratios of 1.69 (95% CI 1.19-2.36) and 1.40 (95% CI 1.02-1.91), respectively. CONCLUSIONS: Both admission hypoMg and hyperMg were associated with an increased risk for in-hospital ARF requiring mechanical ventilation. CLINICAL IMPLICATIONS: Our study demonstrated that admission Mg level was correlated with the incidence of ARF requiring mechanical ventilation during hospitalization so physician should be awared and correct Mg level accordingly.