Hypomagnesaemia in elderly hospital admissions: a study of clinical significance.

Serum magnesium estimations carried out on 1576 consecutive elderly patients at the time of hospital admission revealed that 10.7 per cent had a serum magnesium level below 0.7 mmol/l, with 4.4 per cent of the total having a serum level less than 0.65 mmol/l. Hypokalaemia was frequently associated with hypomagnesaemia, for which diuretic therapy was the most commonly found predisposing factor. Outcome of illness, measured at six months in terms of mortality, duration of hospital stay and percentage of patients discharged from hospital, was no worse in patients admitted with hypomagnesaemia than in normomagnesaemic controls.