Low body weight: a simple indicator of the risk of dehydration among children with diarrhoea.

The early identification of children at high risk of dehydration as a consequence of diarrhoea would be of great value for health care workers in developing countries. By comparing children aged less than two years with diarrhoea and moderate to severe dehydration with matched controls who had uncomplicated diarrhoea, a number of prognostic factors were assessed. Low body weight, regardless of age, was strongly associated with the risk of dehydration; using 7.0 kg as a cut-off, it had a sensitivity of 75% and a specificity of 68%. Low body weight was superior to more complex anthropometric indices, including weight for age, weight for length or length for age, and also to early signs and symptoms during the episode. By reflecting the effects of both young age and those of malnutrition, low body weight may prove to be a simple indicator for predicting dehydration among children with diarrhoea presenting at a health service.