Measures of nutritional status [letter]

The authors defend the use of mid-upper arm circumference (MuU) as a measure of nutritional status. Rees et al have maintained that their comparison of MUAC with conventional measures of wasting (weight-for-height) and stunting (height-for-age) casts doubt on the usefulness of arm circumference in the detection of malnutrition. It is argued however that this type of comparison is meaningless unless related in some way to functional outcomes such as mortality. To determine which indices best measure risk of death sensitivity/specificity curves must be compared. 2 studies from Bangladesh found MUAC to be at least as good as other indices and a study from Zaire showed that arm circumference-for-age gave a better assessment of risk of death than indices related to weight and height. Furthermore one of the Bangladesh studies found that use of various combinations of anthropometric indices including measures of stunting and wasting did not improve the accuracy of MUAC alone for predicting mortality. The value of MUAC as a measure of nutritional status lies both in its ease of use and in its sensitivity and specificity in identifying malnourished children at risk of imminent death. A cut-off point of 110 mm rather than the frequently cited figure of 125 mm is recommended for identifying children in special need of care.