Malnutrition Redefined

Defining malnutrition accurately is the focus of a new report (JPEN 2013; DOI: 10.1177/0148507113479972). Thanks to Kipp Ellsworth for this article.

The Pediatric Malnutrition Definitions Workgroup was formed in April 2010 and makes numerous relevant contributions to precisely defining malnutrition.  The reasons for this workgroup and report are to promote the following:

  • early identification of those at risk for malnutrition
  • allow better comparison of malnutrition prevalence & collect meaningful data
  • develop uniform screening tools
  • develop thresholds for intervention
  • improve assessment of outcomes

“Pediatric malnutrition (undernutrition) is defined as an imbalance between nutrient requirement and intake, resulting in cumulative deficits of energy, protein, or micronutrients that may negatively affect growth, development, or other relevant outcomes.”

First, malnutrition is subdivided into two categories: illness-related malnutrition and non-illness-related malnutrition.  Illness-related malnutrition refers to malnutrition caused by chronic conditions, burns, and surgery.  It is the predominant cause in developed countries.  Non-illness-related malnutrition refers to malnutrition caused by environmental or behavioral factors (including food aversions or anorexia).

Illness-related malnutrition occurs due to nutrient loss, increased energy expenditure, decreased nutrient intake, or altered nutrient utilization.

In brief, patients need to be assessed in five domains: anthropometrics, growth charts, chronicity, etiology/pathogenesis, and functional status.

Summary of recommendations:

  1. Record anthropometric variables on admission and serially.  These measurements include weight, height, BMI, mid-upper arm circumference (MUAC) and consider triceps skin fold (TSF) and mid-arm muscle circumference.  Obtain head circumference if younger than 2 years.
  2. In infants/children <2 years, measure length with recumbent board. In older patients unable to stand, consider alternative measurement like tibia length or knee height for a height proxy.
  3. Use the 2006 World Health Organization growth charts in patients younger than 2 years and the CBC 2000 growth charts for children 2-20 years. In addition, use corrected age (number of weeks/months premature + chronological age) for preterm infants until they are 3 years old.
  4. Use a decline in z score for individual anthropometric measurements as the indication of faltering growth.
  5. Use 3 months as a cutoff to classify as acute or chronic.
  6. Include description of predominant mechanism of malnutrition: decreased intake, increased requirements, excessive losses, or failure to assimilate/malabsorption.
  7. Recognize the role of inflammation on nutrition status.
  8. Assess impact of malnutrition: consider developmental assessment, lean body mass measurements, and measures of muscle strength.

By having a better established uniform definition of malnutrition, impact on outcomes will be easier to assess. In addition to the potential outcomes noted above (#8), others that will need to be examined in relation to malnutrition include length of hospital stay, wound healing, frequency of infections, behavioral problems, and disease-specific resource utilization.

This article also reviews previous definitions and potential problems with their usage.  For example, Waterlow criteria rely on percentiles and standard deviations and are used widely.  In hospitalized children, accurate serial weights and heights can be challenging due to fluid retention and poor mobility.

The authors note that malnutrition is likely underdiagnosed and inadequately treated.  Some recent estimates indicate that malnutrition is present “in 40% of patients with neurologic conditions, 34.5% in those with infectious diseases, 33.3% of those with cystic fibrosis, 28.6% in those with cardiovascular disease, 27.3% in oncology patients, and 23.6% in those with GI diseases. Patients with multiple diagnoses are most likely to be malnourished (43.8%).”

Bottomline: A lot of patients are malnourished.  Recognition of malnutrition (defining what is malnutrition) should improve outcomes.

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