Diagnostic performance of MUAC and MUACZ in screening acute malnutrition among children aged 6–23 months in Amhara Region, Ethiopia

Mid-Upper Arm Circumference (MUAC), Mid-Upper Arm Circumference-for-Age Z-Score (MUACZ),or Weight-for-Length Z-Score (WHZ) are used to screen for acute malnutrition in children. Studiesconducted in various countries, including Ethiopia, have indicated variability in the agreementbetween these assessments at the World Health Organization recommended cutoffs acrossdifferent ethnic groups with varying body frames. The low sensitivity of MUAC at standard cutoffshas important implications for program effectiveness. Therefore, this study aimed to validate thediagnostic performance of MUAC and MUACZ in screening for acute malnutrition among children aged6–23 months in Ethiopia. A community-based cross-sectional study was conducted on 457 randomlyselected children aged 6–23 months in the Amhara Region, Ethiopia, from February 2–18, 2023. TheSpearman’s rank correlation test, Cohen’s kappa statistics, and Receiver Operating Curve analysiswere conducted. The optimal cutoff points for MUAC and MUACZ were determined by selecting thepoints that maximized the Youden index. Statistical significance was determined with a p-value < 0.05,using a 95% confidence interval. MUAC, MUACZ, and WHZ results revealed that 11.0%, 8.6%, and13.2% of children were wasted, respectively, and the percentage of misclassification in screeningacute malnutrition was approximately 16%. MUAC and MUACZ had low sensitivity but high specificityin screening for acute malnutrition. MUAC and MUACZ showed poor correlation with WHZ whenscreening subjects for acute malnutrition using the World Health Organization standard cutoffs. Inthe Receiver Operating Characteristics curve analysis, significant predictive ability was only observedwith MUAC when screening global acute malnutrition cases, and it showed a poor predictive ability(AUC = 0.61, 95% CI: 0.53, 0.70) (p < 0.001). The Youden index statistics revealed that the optimal cutofffor MUAC and MUACZ to define global acute malnutrition at WHZ < -2 SD was 13.6 cm and -0.43 SD,respectively. In addition, the optimal cutoffs for diagnosing severe acute malnutrition in children withWHZ of < -3 SD were found to be 13.1 cm and -1.91 SD for MUAC and MUACZ, respectively. The optimalcutoff values also vary in sex and age categories. Both MUAC and MUACZ had poor performance inscreening acute malnutrition, and a significant proportion of children were missed despite they werewasted as compared to WHZ at the standard cutoffs. The optimal cutoff levels differ for differentage and sex categories. This may affect admission and discharge rates and have a significant impacton children’s health. Modifications in the standard cutoffs are needed to ensure the quality of acutemalnutrition screening and treatment services.