Newborn mid–upper arm circumference identifies low–birth weight and vulnerable infants: A secondary analysis

Authors: HENDRIXSON, D - University Of Washington; LASOWSKI, PATRICK - The Icahn School Of Medicine At Mount Sinai; KOROMA, AMINATA - Ministry Of Health & Sanitation; MANARY, MARK - Washington University

Submitted to: Current Developments in Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2022
Publication Date: 10/12/2022
Citation: Hendrixson, D.T., Lasowski, P.N., Koroma, A.S., Manary, M.J. 2022. Newborn mid–upper arm circumference identifies low–birth weight and vulnerable infants: A secondary analysis. Current Developments in Nutrition. 6(10). Article nzac138. https://doi.org/10.1093/cdn/nzac138.
DOI: https://doi.org/10.1093/cdn/nzac138

Interpretive Summary: Low birth weight (LBW) infants are at an increased risk of medical problems and death, however identification of LBW is often limited by access to reliable scales. We tested the strength of measuring the mid-upper arm circumference (MUAC) of newborns in identifying LBW in sub-Saharan Africa. MUAC can be used to identify infants with LBW and infants at risk for newborn death, with a MUAC < or =9.0 cm showing the highest risk. Future research should investigate the feasibility and effectiveness of using MUAC to identify LBW in other high risk populations in resource constrained environments.

Technical Abstract: Low birth weight (LBW) infants are at an increased risk of morbidity and mortality. Identification of LBW may not occur in settings where access to reliable scales is limited. Mid–upper arm circumference (MUAC) may be an accessible, low-cost measure to identify LBW and vulnerable infants. We explored the validity of newborn MUAC in identifying LBW and vulnerable newborns in rural Sierra Leone. This study was a secondary analysis of infant data from a randomized controlled clinical trial of supplementary food and anti-infective therapies compared with standard care for undernourished pregnant women. Data for singleton liveborn infants with birth measurement and 6-mo survival data were included in this analysis. The primary outcome was validity of MUAC in identifying low–birth weight (LBW) neonates. Secondary outcomes included validity of MUAC and head circumference (HC) in identifying weight-for-length z-score (WLZ) <-2, length-for-age z-score (LAZ) <-2, neonatal mortality, and mortality within the first 6 mo of life. The study population included 1167 infants, 229 (19.6%) with LBW. Birth MUAC (r = 0.817) and HC (r = 0.752) were highly correlated with birth weight. MUAC (AUC: 0.905; 95% CI: 0.884, 0.925) performed superiorly to HC (AUC: 0.88; 95% CI: 0.856, 0.904) in identifying LBW. The MUAC for identifying LBW was 9.6 cm (sensitivity: 0.86; specificity: 0.78). Neither MUAC nor HC reliably identified newborns with WLZ <-2 or LAZ <-2. MUAC < or =9.0 cm was the ideal cutoff for neonatal mortality (sensitivity: 53.3%; specificity: 89.7%; HR: 9.57; 95% CI: 1.86, 49.30). Birth anthropometrics did not reliably identify infants at risk of death in the first 6 mo of life. MUAC was used successfully to identify LBW infants and infants at risk of neonatal mortality in Sierra Leone. Further evidence is needed to support increased use of newborn MUAC measurement to identify LBW infants and infants at risk of neonatal mortality in community settings where scales are not available. Primary trial was registered at clinicaltrials.gov as NCT03079388.