Arm circumference ν. Arm circumference/head circumference ratio in the assessment of malnutrition in rural Malawian children

Summary: The arm circumference/head circumference ratio (AC/HC) was compared with arm circumference (AC) alone in the diagnosis of protein-energy malnutrition (PEM) in 685 Malawian children between the ages of 3 and 48 months. The AC/HC ratio correlates well, r=0.6863 (P< 0.001), with weight-for-age (WA).The sensitivity and specificity were calculated for both indicators compared to the NCHS reference standard of WA. Compared to 80 per cent WA, the 0.310 AC/HC cut-off was 92 per cent sensitive and 41 per cent specific, while the 0.290 AC/HC cut-off was 75 per cent sensitive and 74 per cent specific. AC alone in the 6-12-month-old children was 75 per cent sensitive and 89 per cent specific at a cut-off of 12.5 cm. In the children from 12 to 48 months with a cut-off of 13.5 cm the AC was 82 per cent sensitive and 70 per cent specific. The AC alone was more sensitive than AC/HC at all levels of specificity.Adding the HC to AC offered no advantage in screening for PEM in these children. In fact, if one were to use the standard 0310 cut-off for AC/HC, the resulting low (41 per cent) specificity would identify such a large proportion of false positives as to make this ratio impractical for field use where it is most needed-in primary health care programmes with low resources which serve populations with high prevalences of PEM.