Operational implications of using 2006 World Health Organization growth standards in nutrition programmes: secondary data analysis.

OBJECTIVE: To assess the implications of adopting the World Health Organization 2006 growth standards in combination with current diagnostic criteria in emergency and non-emergency child feeding programmes.
DESIGN: Secondary analysis of data from three standardised nutrition surveys (n=2555) for prevalence of acute malnutrition, using weight for height z score (<-2 and <-3) and percentage of the median (<80% and <70%) cut-offs for moderate and severe acute malnutrition from the National Center for Health Statistics/WHO growth reference (NCHS reference) and the new WHO 2006 growth standards (WHO standards).
SETTING: Refugee camps in Algeria, Kenya, and Bangladesh. Population Children aged 6-59 months.
RESULTS: Important differences exist in the weight for height cut-offs used for defining acute malnutrition obtained from the WHO standards and NCHS reference data. These vary according to a child's height and according to whether z score or percentage of the median cut-offs are used. If applied and used according to current practice in nutrition programmes, the WHO standards will result in a higher measured prevalence of severe acute malnutrition during surveys but, paradoxically, a decrease in the admission of children to emergency feeding programmes and earlier discharge of recovering patients. The expected impact on case fatality rates of applying the new standards in conjunction with current diagnostic criteria is unknown.
CONCLUSIONS: A full assessment of the appropriate use of the new WHO standards in the diagnosis of acute malnutrition is urgently needed. This should be completed before the standards are adopted by organisations that run nutrition programmes targeting acute malnutrition.