Magnesium Derangement among Critically Ill Patients with Acute Kidney Injury: An Association with Acute Kidney Disease

Introduction: The association between magnesium level and progression to acute kidney disease (AKD) in acute kidney injury (AKI) patients was not well studied. With AKI transition to AKD, the burden of the disease on mortality, morbidity, and healthcare costs increases. Serum magnesium disturbances are linked with a decline in renal function and increased risk of death in CKD and hemodialysis patients. This study aims to assess the significance of magnesium derangements as a risk factor for the progression of AKI to AKD in critically ill patients. Methods: This study was conducted among patients with AKI admitted to the intensive care units at Mayo Clinic from 2007 to 2017. Serum magnesium at AKI onset was categorized into five groups of <1.7, 1.7-1.9, 1.9-2.1, 2.1-2.3, and >= 2.3 mg/dL, with 1.9-2.1 mg/dL as the reference group. AKD was defined as AKI that persisted >7 days following the AKI onset. Logistic regression was used to evaluate the association between magnesium and AKD. Results: Among 20,198 critically ill patients with AKI, the mean age was 66 +/- 16 years, and 57% were male. The mean serum magnesium at AKI onset was 1.9 +/- 0.4 mg/dL. The overall incidence of AKD was 31.4%. The association between serum magnesium and AKD followed a U-shaped pattern. In multivariable analysis, serum magnesium levels were associated with increased risk of AKD with the odds ratio of 1.17 (95% CI: 1.07-1.29), 1.13 (95% CI: 1.01-1.26), and 1.65 (95% CI: 1.48-1.84) when magnesium levels were <1.7, 2.1-2.3, and >= 2.3 mg/dL, respectively. Conclusion: Among patients with AKI, magnesium level derangement was an independent risk for AKD in critically ill AKI patients. Monitoring serum magnesium and proper correction in critically ill patients with AKI should be considered an AKD preventive intervention in future trials.