Mid-upper-arm-circumference and mid-upper-arm circumference z-score: the best predictor of mortality?

BACKGROUND/OBJECTIVE: Mid-upper-arm circumference (MUAC) is a simple method of assessing nutritional status in children above 6 months of age. In 2007 World Health Organization (WHO) introduced a MUAC z-score for children above 3 months of age. We evaluated whether MUAC or MUAC z-score had the best ability to identify children with high short-term mortality risk in Guinea-Bissau. SUBJECTS/METHODS: The Bandim Health Project visits children 3-monthly until 3 years of age. MUAC is measured and deaths are registered. We studied a high-mortality cohort of children born in 1995-96 and a lower mortality cohort of children born in 2005-06. The prognostic ability of MUAC and MUAC z-score to predict mortality within 1 and 3 months after the MUAC assessment were compared by area under the receiver operating characteristic curve, sensitivity and positive predictive value. RESULTS: Compared with MUAC z-score, MUAC identified as malnourished more girls than boys (prevalence ratio (PR) 1.74 (1.52; 2.01)) and more children aged 6-11 months than children aged 12-35 months (1.59 (1.38; 1.82)). There was no difference in the prognostic ability of MUAC and MUAC z-score to predict mortality for children aged 6-35 months. The prognostic ability was higher when mortality was lower. MUAC performed well in the youngest infants. CONCLUSION: In the age group 6-35 months, MUAC and MUAC z-score had the same prognostic ability to predict short-term mortality. As MUAC is easier to use in field settings, there is no need to use MUAC z-score to identify children with a high-mortality risk.