Hypomagnesemia as a risk factor for the non-recovery of the renal function in critically ill patients with acute kidney injury.

BACKGROUND The aim of this study was to evaluate the role of hypomagnesemia as a risk factor for the development of acute kidney injury (AKI) and non-recovery of renal function in critically ill patients. METHODS A cohort study was conducted by collecting data from March to June 2011 in 232 patients who were admitted into an intensive care unit (ICU). Magnesium serum levels were measured daily during ICU stay. Hypomagnesemia was defined as an episode of serum magnesium concentration of <0.70 mmol/L during ICU stay. The Risk, Injury, Failure, Loss and End-stage kidney disease (RIFLE) criteria were used to define AKI. Renal function recovery was defined as an absence of AKI by the RIFLE criteria over a 48-h period, or at ICU discharge, in the patients who developed AKI during ICU stay. RESULTS The presence of hypomagnesemia was similar in patients with or without AKI (47 and 62%, respectively, P = 0.36). The presence of hypomagnesemia was higher in patients who did not recover renal function when compared with patients who recovered renal function (70 versus 31%, P = 0.003). A multivariate analysis identified hypomagnesemia as an independent risk factor for non-recovery of renal function (P = 0.005). Patients with and without hypomagnesemia had similar mortality rates (P = 0.63). CONCLUSIONS Hypomagnesemia was an independent risk factor for non-recovery of renal function in a cohort of critically ill AKI patients.