New world health organization guideline on anemia cut-off points: implications for children aged 6-35 months in Peru.

Background: Motivation for the study. In 2024, the World Health Organization modified the cut-off points that define anemia. The magnitude of the change in the prevalence of anemia in children aged 6-35 months in Peru, compared to the 2001 guideline, is unknown. Main findings. Between 2009 and 2023, we found significant and heterogeneous differences (a) nationally, (b) between and within regions, and (c) depending on the calculation technique (table or equation). Implications. The rationale for the 2024 guideline, while much better than that for the 2001 guideline, is not sufficient. The new guideline should be adopted with caution, both in individual care and population-related decisions.

Objectives.: To compare annual national and regional prevalence rates of anemia, using the 2001 guideline versus the new 2024 guideline in children aged 6 to 35 months residing in Peru between 2009 and 2023. To assess whether differences exist between guidelines vary by region, setting, or year.

Materials and methods.: Secondary analysis of the Demographic and Family Health Survey (continuous national random sample, stratified and clustered). Hemoglobin was measured in capillary blood using Hemocue. We applied an equation (and/or table) for altitude adjustment and a cutoff point for each guideline. We calculated 95% confidence intervals [95% CI]. Differences were evaluated according to region, setting, and/or year using a generalized linear model, calculating extremes and quartiles. Estimates and models were weighted.

Results.: We analyzed 120,711 children. The difference in prevalence was -6.3 [-6.6 to -6.0], p<0.001, varying by region (p<0.001), region-year (p=0.004), and region-setting (p<0.001), between -40.6 and 11.0. The percentage of children whose diagnosis differed was 11.0 [10.7 to 11.2], (p<0.001), varying between 0.0 and 40.6. The difference between the table and the equation was -3.8 [-4.0 to -3.6].

Conclusions.: The prevalence differs with the new guideline (generally decreasing, but may increase), with variable differences according to region, setting, and year. The percentage with a different diagnosis also varies. These differences are of great importance for health, in some cases changing the problem from severe to moderate. The table calculation underestimates the equation calculation. Literature supports the direction of the correction, but not its magnitude.

Background: Motivation for the study. In 2024, the World Health Organization modified the cut-off points that define anemia. The magnitude of the change in the prevalence of anemia in children aged 6-35 months in Peru, compared to the 2001 guideline, is unknown. Main findings. Between 2009 and 2023, we found significant and heterogeneous differences (a) nationally, (b) between and within regions, and (c) depending on the calculation technique (table or equation). Implications. The rationale for the 2024 guideline, while much better than that for the 2001 guideline, is not sufficient. The new guideline should be adopted with caution, both in individual care and population-related decisions.