Burden of anthropometric failures and concordance of mid-upper arm circumference with weight for length z score in identifying malnutrition among under 2-year-old children in Southern India

Objective: To assess anthropometric failure prevalence using a composite index of anthropometric failure and evaluate the concordance of mid-upper arm circumference (MUAC) with weight for length z score (WLZ) in identifying acute malnutrition in children. Design: We used data from a pre-proof-of-concept (pre-POC) study conducted in 2022–2023. Setting: The study was conducted in the Vellore district in Tamil Nadu, South India. Participants: We included all children aged 5–19 months who were pre-screened for the pre-POC study and had available data on weight, length, MUAC, date of birth and child sex. Results: A total of 663 children were available for analysis, with a mean age of 11·4 months. The prevalence of underweight, stunting and wasting was 23·8 %, 24·3 % and 16·6 %, respectively. 36·7 % of the children had at least one form of anthropometric deficit, and 8·2 % showed severe deficits. We found a fair agreement between MUAC and WLZ values (kappa = 0·32) and a poor agreement of kappa = 0·19 and 0·10 with weight for age z score (WAZ) and length for age z score (LAZ), respectively. Conclusions: The prevalence of malnutrition remains a significant public health concern in South India, with rates consistent with previous literature. MUAC and WLZ cutoffs by the WHO identify different groups with acute malnutrition. Community-based studies using WLZ criteria can adopt screening with higher MUAC cutoffs, followed by WLZ or, alternatively, WAZ alone, as low WAZ covers most participants with low MUAC and WLZ, providing better feasibility. However, the optimal measurement for risk identification requires further exploration.