Abnormal magnesium levels and their impact on death and acute kidney injury in critically ill children

Background The prevalence of magnesium imbalance in critically ill children is very high. However, its significance in the development of acute kidney injury (AKI) and mortality remains unknown. Methods In this retrospective observational study from 2010 to 2018, the pediatric-specific intensive care database was analyzed. We included critically ill children aged > 3 months and those without chronic kidney disease. Patients were diagnosed with AKI, according to the Kidney Disease Improving Global Outcomes (KDIGO) study. We calculated the initial corrected magnesium levels (cMg) within 24 h and used a spline regression model to evaluate the cut-off values for cMg. We analyzed 28- day mortality and its association with AKI. The interaction between AKI and magnesium imbalance was evaluated. Results The study included 3,669 children, of whom 105 died within 28 days, while 1,823 were diagnosed with AKI. The cutoff values for cMg were 0.72 and 0.94 mmol/L. Both hypermagnesemia and hypomagnesemia were associated with 28-day mortality (odds ratio [OR] = 2.99, 95% confidence interval [CI] = 1.89-4.71, p < 0.001; OR = 2.80, 95% CI = 1.60-4.89, p < 0.001). Hypermagnesemia was associated with AKI (OR = 1.52, 95% CI = 1.27-1.82, p < 0.001), while neither hypermagnesemia nor hypomagnesemia interacted with the AKI stage on the 28-day mortality. Conclusions Abnormal magnesium levels were associated with 28-day mortality in critically ill children. AKI and hypermagnesemia had a strong association.