Comparison of the prevalence of acute malnutrition in children aged 6-59 months by mid-upper arm circumference and weight-for-height index in Democratic Republic of the Congo from 2020 to 2022

Background Acute malnutrition in children under five remains a major public health crisis in the Democratic Republic of the Congo (DRC). This study aimed to compare the diagnostic performance and concordance of the Weight-for-Height (W/H) index and Mid-Upper Arm Circumference (MUAC) in children aged 6–59 months, utilizing comprehensive recent data. Methods This analysis used secondary data from 20 SMART surveys conducted by PRONANUT between 2020 and 2022, resulting in a final sample of 16.427 children. MUAC performance was assessed by calculating sensitivity, specificity, and the Cohen’s Kappa coefficient to measure agreement with W/H, which served as the reference standard. Results The overall prevalence of global acute malnutrition was 10.9% by W/H and 12.9% by MUAC. The analysis revealed a very poor concordance (Kappa = 0.030), with only 4.4% of cases identified by both methods. MUAC showed high specificity (90.4%), but critically low sensitivity (40.6%), indicating it misses a large majority of true wasting cases. Conclusions The findings highlight a poor diagnostic overlap, confirming that the two tools identify distinct populations. Relying solely on MUAC risks significant underestimation of malnutrition and failure to link vulnerable children to care. We recommend a differentiated strategy: using MUAC for community triage (screening) and maintaining W/H for clinical diagnosis and admission in therapeutic feeding centers to ensure comprehensive case management.