Hypomagnesemia and mortality in patients admitted to intensive care unit: a systematic review and meta-analysis

Background: Reports of mortality due to magnesium dysregulation in the critical care setting are controversial. We performed a systematic review and meta-analysis to evaluate the association between hypomagnesemia and mortality in patients admitted to the intensive care unit. Methods: Eligible studies assessing the association between hypomagnesemia or hypermagnesemia and mortality in the critical care setting were comprehensively searched in MEDLINE and EMBASE from their inception to September 2015. Inclusion criteria were published observational studies in adults who were admitted to the intensive or critical care setting with initial serum magnesium measurement. We used the definition of abnormal magnesium level defined by each study. Primary outcome was all-cause mortality. We performed meta-analysis using random-effects model and calculated pooled effect estimate of outcome comparing between hypomagnesemia and normal magnesium category. Results: From 30 full-text articles, 6 studies involving 1550 participants were included in the meta-analysis. There was a statistically significant higher risk of mortality in critically ill patients who had hypomagnesemia with RR of 1.90 (95% CI: 1.48-2.44, P < 0.001, I-2 = 63.5%). Risk for needing mechanical ventilation was also higher in the hypomagnesemia group with RR of 1.65 (95% CI: 1.12-2.43, P = 0.01, I-2 = 84%). Length of ICU stay was also higher in the hypomagnesemia group with mean difference of 4.1 days (95% CI: 1.16-7.04, P = 0.01). Conclusion: The findings of this meta-analysis indicate hypomagnesemia is associated with higher mortality, the need of mechanical ventilation and also the length of ICU stay in patients admitted to ICU.