Redefining childhood anemia in Peru: district-level variations after the adoption of the WHO 2024 guidelines

Objective: To determine and compare the prevalence of anemia in children under five years of age receiving care in public health centers in Peru, using the CDC 1989 and WHO 2024 criteria, and to analyze the relevance of these prevalences in the classification of public health significance. Materials and methods: This ecological study compared the prevalence of anemia in children under five in Peru according to the CDC 1989 and WHO 2024, using data from the Sistema de Información del Estado Nutricional (SIEN). Hemoglobin adjustment equations for altitude were applied, and anemia was defined according to both criteria. Data analysis was conducted in RStudio using descriptive statistics, alluvial diagrams, and choropleth maps to classify and compare anemia prevalence at the district level. Results: The prevalence of anemia in children aged 6 to 23 months was 24.8% (CDC) and 17.0% (WHO). In children aged 24 to 59 months, it was 14.3% (CDC) and 18.8% (WHO). In areas ≥3500 m a.s.l., prevalence decreased from 31.3% (CDC) to 15.8% (WHO), while in altitudes between 500 and 2500 m a.s.l., anemia prevalence increased with the WHO 2024 criteria. At the district level, a reclassification was observed, with Andean highland districts reducing their public health importance category, while some Amazonian regions showed increases. Conclusions: The adoption of the WHO 2024 criteria substantially modifies the estimated prevalence of anemia in children under five attending public health facilities in Peru.