Scope and purpose
The World Health Organization (WHO) has initiated a project to review global guidelines on haemoglobin cutoffs to define anaemia. The activities include retrieving, summarizing and assessing the currently available evidence to inform updated WHO recommendations on the use and interpretation of haemoglobin concentrations for assessing anaemia in individuals and in populations.
Based on priority questions and research needs posed by experts after a public call and in review of the priorities outlined in the 2030 Sustainable Development Goals, the WHO Department of Nutrition and Food Safety convened a Technical meeting on the use and interpretation of haemoglobin concentrations for assessing anaemia status in individuals and populations in December 2017. The outcomes of this meeting1 served as the foundation for developing a scoping document for producing the key questions to be addressed in the revised guidelines. The first guideline development group meeting was held in November 20192 where the final key questions were agreed. One of the key questions related to the review of evidence on the need for adjustments in haemoglobin concentrations to account for differences in settings and populations. A virtual technical meeting was held in October 2020, to evaluate the available evidence and consider adjustments of haemoglobin concentrations to define anaemia by elevation above sea level of the place of residency/work and cigarette smoking.
Other key question identified during the first guideline development group meeting was the establishment of haemoglobin cutoffs for defining anaemia during the lifespan, particularly in infants, children and pregnant women.
To address this issue, WHO is convening a technical meeting on considerations to determine haemoglobin concentrations to define anaemia during the lifecycle particularly in infants, children, adolescents and pregnant women by trimester of gestation and postpartum.
This will be a virtual meeting on 27-29 April 2021 (13:00 – 16:15 CET)
The objectives of the meeting are to:
- Present and discuss evidence on the basis for the revision of the cutoffs to define anaemia:
- Statistical approach (a 95% reference range in normal individuals). In this scenario: What is the reference range [distribution] of haemoglobin concentrations in apparently healthy population?
- Functional/clinical outcomes. In this scenario: What are the haemoglobin cut-offs below which clinical symptoms or functional impairments are noted to occur in apparently healthy individuals or populations of interest?
- Once the criteria for classification is stablished, present and discuss evidence to define the haemoglobin cutoffs to define anaemia in individuals and populations considering differences by age groups (0-5 months, 6-23 months, 24-59 months, 5-9 years, 10-19 years, 20-59 years, 60-74 years and 75+ years), sex and trimester of pregnancy.
- Present and discuss evidence to define the haemoglobin cutoffs defining mild, moderate and severe anaemia in individuals.
- Present and discuss evidence to define the haemoglobin cutoffs defining mild, moderate and severe public health burden of anaemia.
- Discuss implications for implementation and evaluation of potential changes.
- To define needs for further research.
The outcomes of this meeting will be presented at a second guideline development group meeting for further consideration.
1 Garcia-Casal MN, Pasricha SR, Sharma AJ, Peña-Rosas JP. Use and interpretation of hemoglobin concentration for assessing anaemia status in individuals and populations: results from a WHO technical meeting. Ann NY Acad Sci. 2019;1450:5-14. https://doi.org/10.1111/nyas.13900