New WHO guideline on the definition of anemia: implications for 6-35 months old children in Peru 2009-2023

IntroductionThe World Health Organization recently published a guideline updating the cut-off points defining anemia, modifying the age and altitude adjustments and recommending auto-analyzers. We compute in a national sample the magnitude of anemia prevalence with the previous and current guidelines between 6 and 35 months old and discuss the implications. MethodsSecondary analysis of the Peruvian Demographic and Health Survey 2009-2023, a repeated cross-sectional design upon a national stratified and cluster random sample. Results117995 children were included. With the new guideline, the national prevalence is reduced and the regional prevalences are generally reduced (some increased) in variable amounts. Conclusions and RecommendationsThe comparison confirms that the new guideline modifies, mostly reducing, the prevalence in an important and heterogeneous magnitude. Literature supports the direction, but not the magnitude of the correction. We recommend the quick, but cautious and gradual adoption of the new guideline. For analytic calculations, age and altitude formulas (not categories) should be used. Surveillance must be reinforced and control strategies must be reviewed. Case management guidelines must be updated.