Agreement and clinical relevance of mid-upper arm circumference in acute, chronic, and concurrent pediatric malnutrition: A retrospective cross-sectional study.

Mid-upper arm circumference (MUAC) is widely used for screening pediatric malnutrition due to its simplicity and feasibility. Although its relationship with anthropometric indicators including weight-for-height (WFH), body mass index (BMI)-for-age, and height-for-age has been previously examined, the degree of agreement and its clinical implications remain variable. This study aimed to evaluate the agreement and clinical relevance of MUAC in assessing acute, chronic, and concurrent malnutrition. This retrospective cross-sectional study included 473 children (0-18 years) evaluated for malnutrition at a tertiary pediatric gastroenterology clinic. Nutritional status was classified using World Health Organization growth standards based on WFH, BMI-for-age, and height-for-age z-scores. MUAC was analyzed as absolute values and MUAC-for-age z-score categories. Acute malnutrition was identified in 72.9% of participants, chronic malnutrition in 18.2%, and concurrent malnutrition in 8.9%. MUAC classified 83.7% of children as malnourished and detected a higher proportion of mild malnutrition than BMI-for-age and WFH classifications. MUAC severity showed a moderate correlation with WFH classifications in children <5 years (ρ = 0.447, P <.001) and a strong correlation with BMI-for-age classifications in those ≥ 5 years (ρ = 0.649, P <.001). Agreement between MUAC-based severity categories and anthropometric classifications was fair for WFH (κ = 0.33) and moderate for BMI-for-age (κ = 0.55). Children with concurrent malnutrition were more frequently classified into moderate or severe MUAC categories (P <.01). MUAC showed fair-to-moderate agreement and moderate-to-strong correlations with BMI-for-age and WFH indicators of acute malnutrition, whereas its associations with chronic malnutrition were weaker. It identifies a higher proportion of children with mild malnutrition and reflects the severity of concurrent malnutrition. These findings support the potential complementary role of MUAC in routine anthropometric assessment and suggest that it may contribute to the early identification of pediatric malnutrition.