Prevalence of Global Acute Malnutrition (GAM) Based on MUAC

Impact

% of children aged 6–59 months with MUAC <125 mm and/or bilateral pitting oedema

The indicator measures the prevalence of global acute malnutrition (GAM) based on MUAC among children aged 6–59 months: MUAC <125 mm and/or bilateral pitting oedema. Moderate wasting based on MUAC is defined as MUAC ≥115 mm and <125 mm without bilateral pitting oedema. Severe acute malnutrition based on MUAC and/or oedema is defined as MUAC <115 mm and/or bilateral pitting oedema.

Collect the data through a probability-based survey that is representative of the population and geographic area for which the prevalence estimate will be reported. Data can be collected as part of a SMART survey or through a survey designed specifically to estimate GAM based on MUAC. A MUAC-only survey is appropriate when the intended indicator is specifically GAM based on MUAC and adequate sampling and data-quality procedures can be maintained; its result should not be treated as interchangeable with GAM based on weight-for-height.

For each selected child aged 6–59 months, measure MUAC on the left arm at the midpoint between the shoulder and elbow using a standard MUAC tape, recording the measurement to the nearest millimetre. Assess the child for bilateral pitting oedema using the standard technique on both feet. Enumerators should receive practical training and undergo standardisation before data collection.

Calculate the indicator by dividing the number of surveyed children aged 6–59 months with MUAC <125 mm and/or bilateral pitting oedema by the total number of surveyed children aged 6–59 months with valid measurements. Multiply the result by 100 to express it as a percentage. Report the result with a 95% confidence interval and account for the survey design, including clustering and sampling weights where relevant. Check overall survey quality using SMART guidance and MUAC-specific data quality using IPC guidance.

This data can be disaggregated by sex, age group and geographic area.

1) This indicator requires reliable identification of whether a child is aged 6–59 months. Exact age in months is also important for age disaggregation and some MUAC data-quality checks, but the fixed MUAC cut-off itself is not age-adjusted. Whenever possible, verify the child’s age using a birth certificate, vaccination card or another reliable document. If such documents are unavailable or their accuracy is uncertain, use a locally adapted events calendar to help estimate the child’s age. See FAO’s guidance below for advice on preparing and using local events calendars.

    

2) Prevention-oriented projects should use this indicator only if their strategy is likely to have an impact on the nutritional status of the target population. If your project is too short or focuses, for example, primarily on improving agricultural production, use less ambitious indicators measuring, for example, nutritional intake (such as Minimum Dietary Diversity) or specific nutritional practices.

  

3) In many countries, acute malnutrition is prone to significant seasonal differences (e.g. ranging from 5% in the months following the harvest to 11% before the harvest). Therefore, if you need to compare your baseline and endline data to assess the result of your work, ensure that the data is collected at the same time of year; otherwise, you will receive two sets of data which say very little about the change your project has (not) achieved.

  

4) Determine the required sample size from the expected prevalence, desired absolute precision, survey design effect, anticipated non-response and intended use of the results. SMART considers approximately ±3 percentage points sufficient for many GAM surveys, while requiring substantially narrower confidence intervals can result in unnecessarily large samples. Training and fieldwork duration should likewise be determined by the survey design and the team’s demonstrated competence. Training must include practical measurement, oedema assessment, piloting and standardisation, with further practice or retraining where performance is inadequate.

5) Always report this result as GAM based on MUAC. Do not assume that it is interchangeable with GAM based on weight-for-height or apply weight-for-height prevalence thresholds to it. MUAC and weight-for-height identify overlapping but different groups of children.

6) Establish a referral procedure before starting data collection. Children identified with low MUAC or bilateral pitting oedema should be referred in accordance with national protocols. Children with MUAC <115 mm and/or bilateral pitting oedema require prompt full assessment for severe acute malnutrition.

Also consider using the following indicators:

• Prevalence of Global Acute Malnutrition (GAM) Based on WHZ (provides the complementary WHZ-based estimate and helps avoid treating MUAC and WHZ prevalence as interchangeable)

• Coverage of MUAC Screening (measures whether children are being reached for routine detection and referral)

• Coverage of Acute Malnutrition Treatment Services (links the measured burden of acute malnutrition to access to treatment)