title: Development of ionized hypomagnesemia is associated with higher mortality rates.
abstract: OBJECTIVE
  Previous studies have shown a wide variation in the prevalence of total serum hypomagnesemia in intensive are unit (ICU) patients and in associated mortality rates. As the ionized part of magnesium is the active portion, we sought to define the prevalence of ionized hypomagnesemia in critically ill patients and to evaluate its relationship with organ dysfunction, length of stay, and mortality.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  A 31-bed, medical-surgical, university hospital ICU.
  
  
  METHODS
  A total of 446 consecutive patients admitted to the ICU over a 3-month period.
  
  
  METHODS
  None.
  
  
  RESULTS
  The ionized magnesium level (normal value, 0.42-0.59 mmol/L) was measured at admission and then every day until discharge from the ICU. At admission, 18% of patients had ionized hypomagnesemia, 68% had normal ionized magnesium levels, and 14% had ionized hypermagnesemia. There was no significant difference in the length of stay or in the mortality rate between these three groups of patients. Hypomagnesemic patients more frequently had total and ionized hypocalcemia, hypokalemia, and hypoproteinemia. A total of 23 patients developed ionized hypomagnesemia during their ICU stay; these patients had higher Acute Physiology And Chronic Health Evaluation II (14.9 +/- 5.4 vs. 11.0 +/- 6.2) and Sequential Organ Failure Assessment (SOFA; 7.1 +/- 5.4 vs. 3.9 +/- 2.8) scores at admission (p <.01 for both), a higher maximum SOFA score during their ICU stay (10.0 +/- 5.6 vs. 4.4 +/- 3.2, p <.01), a higher prevalence of severe sepsis and septic shock (57 vs. 11%, p <.01), a longer ICU stay (15.4 +/- 15.5 vs. 2.8 +/- 4.7 days, p <.01), and a higher mortality rate (35% vs. 12%, p <.01) than the other patients. The major risk factors for developing hypomagnesemia during the ICU stay were a prolonged ICU stay, treatment with diuretics, and sepsis.
  
  
  CONCLUSIONS
  Development of ionized hypomagnesemia during an ICU stay is associated with a worse prognosis. It is often associated with the use of diuretics and the development of sepsis. Monitoring of ionized magnesium levels may have prognostic, and perhaps therapeutic, implications.
authors.affiliation: Department of Intensive Care, Erasme University Hospital, Free University of Brussels, Belgium.
authors.forename: Hosam M
authors.initials: HM
authors.lastname: Soliman
authors.forename: Dany
authors.initials: D
authors.lastname: Mercan
authors.forename: Suzana S M
authors.initials: SS
authors.lastname: Lobo
authors.forename: Christian
authors.initials: C
authors.lastname: Mélot
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Vincent
mesh_terms: D018806:APACHE; D016638:Critical Illness / Q000401:mortality*; D004232:Diuretics / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007902:Length of Stay; D016015:Logistic Models; D008274:Magnesium / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009102:Multiple Organ Failure / Q000175:diagnosis; D011379:Prognosis; D012307:Risk Factors
chemical_list: D004232:Diuretics; D008274:Magnesium