Hypomagnesaemia in patients hospitalised in internal medicine is associated with increased mortality

Magnesium is the major intracellular divalent cation. Hypomagnesaemia is common among critically ill patients; it's prevalence is not known in patients admitted to general internal medicine. We sought to quantify hypomagnesaemia, and attempted to correlate it with clinical outcomes in internal medicine patients.

Retrospective chart review. Hypomagnesaemic patients admitted from 1 October 2010 through 18 November 2010 compared with normomagnesaemic patients. Laboratory tests, medical and demographic data were analysed.

In 627 consecutive admissions, overall frequency of hypomagnesaemia was 20.1% (87 patients). Hypomagnesaemic patients were a little older (mean age of 75) and more likely to be women (62%). There was a significant difference in mortality between the normomagnesaemic group (7.2%) and the hypomagnesaemic group (17.2%) (p = 0.0067). There was also a significant difference for length of stay (5.00 ± 5.3 vs. 7.0 ± 8.2, p = 0.0001).

The prevalence of hypomagnesaemia in internal medicine is very high. It is associated with higher mortality and longer hospital stay in our population. It can be a useful tool in predicting morbidity and mortality. Although no causal role can be defined for it at present, the low cost and minimal discomfort of measuring magnesium justifies its routine measurement and replacement in patients hospitalised in internal medicine.