Intravenous magnesium load test in elderly patients with protein-energy malnutrition.

Forty-two elderly patients were subjected to a nutritional assessment and an intravenous magnesium load (0.5 mmol/kg). After 48 h, patients with protein-calorie malnutrition (PCM) showed magnesium retentions (MgR) above 20 per cent, thus indicating magnesium deficit, and greater (P < 0.001) than those from well-nourished patients. The discriminating cross-point for undernourished patients was at 28 per cent with 95 per cent sensibility and specificity. There were significant correlations between MgR and most nutritional parameters. An increase of the RMg constitutes a PCM indicator which may be useful to quantify it.