MUAC as discharge criterion and weight gain in malnourished children

Summary of published research¹

A child on admission to the Gedaref nutrition programme

In addition to guidance on admission criteria for nutrition programmes, the WHO and UNICEF 2009 Joint Statement also gave some guidance regarding discharge criteria in nutrition programmes using mid upper arm circumference (MUAC) on admission, recommending discharging children after reaching a 15-20% weight gain². This was done with the intention of removing the need for height measurement and avoiding the problem of children meeting a MUAC admission criterion but having a weight for height z score (WHZ) above the discharge criterion. Using percent weight gain as the discharge criterion has the disadvantage of requiring a smaller absolute weight gain to meet discharge criteria for children with the lowest initial weight (i.e. the most severely malnourished children). This leads to shorter duration of treatment for the most malnourished children, as weight gain is higher in the most wasted children receiving appropriate treatment. Shorter treatment of the most severely malnourished is of concern and needs to be addressed. Prolonged length of stay for some children also has considerable consequences for on-going government programmes in resource scarce settings. Based on the difficulties with the current recommendation of percent weight gain for discharge and on evidence that MUAC and weight respond to treatment in similar ways, a decision was made by MSF Switzerland to use MUAC as both admission and discharge criteria in an emergency nutrition programme in Gedaref, North Sudan.

The objective of a recent paper was to evaluate the policy of using MUAC as the discharge criterion in outpatient therapeutic programmes (OTP) and more specifically to see whether it eliminates the effect of shorter treatment duration in most severely malnourished children as observed with percent weight gain.

In July 2010, MSF Switzerland, in collaboration with the Ministry of Health, launched an emergency nutrition programme in the localities Gala Alnahal and Al Guiresha in Gedaref, North Sudan. The programme treated malnourished children in a community based therapeutic feeding programme in four Stabilisation Centres (SCs) and 77 OTPs. Children aged 6 to 59 months with MUAC <115 mm and/or mild oedema had an initial assessment by a physician or medical assistant for the presence of diarrhoea, vomiting, anorexia, anaemia (based on conjunctiva pallor), and fever. The children were also checked for malaria parasitaemia using a rapid diagnostic test, and whether they had previously been immunized against measles. Children with good appetite and no severe medical complications (i.e. severe anaemia shock, sepsis, severe dehydration, anorexia, severe oedema) were classified as having uncomplicated severe acute malnutrition (SAM) and admitted to the OTP. Children in the OTP received Ready to Use Therapeutic Food (RUTF) as per WHO guidelines. All children with MUAC<115 mm with severe medical complications and those requiring 24-hour close observation were hospitalised in a SC until they were stable enough to be transferred to an OTP, following the CMAM approach. Children requiring stabilization were referred to the nearest MSF SC with transportation provided by MSF.

All children in the programme had their height, weight, MUAC and oedema checked at admission. Weight, MUAC and oedema were checked at each visit, and weight and MUAC were checked at discharge. UNICEF MUAC bracelets were used to measure MUAC to the nearest millimetre. Most children were checked every two weeks except for some children who attended the four OTP sites located beside four inpatient facilities who were seen every week.

The following criteria for discharge were required: MUAC >125 mm for two consecutive measurements plus stable weight or continuing weight gain, absence of bilateral oedema for four weeks, and clinically well and with good appetite. MUAC cut off for discharge was set at 125 mm based on evidence that there is very low mortality in children with MUAC above 125 mm.

All children aged 6-59 months with a MUAC <115 mm on admission who were discharged as cured from the OTP were included in the study. The study was limited to children admitted directly to the OTP as duration of treatment and weight gain during the stabilisation phase is mainly influenced by associated medical complications and largely unrelated to response to therapeutic feeding. This also excluded from the analysis children with severe oedema who were treated initially in a SC. These children receive a low-protein, low-energy diet at the beginning of treatment which does not allow for new tissue synthesis and weight change during these initial days and is more related to body water elimination than to synthesis of new tissues. The decision to use MUAC as discharge criteria was made by MSF for programmatic reasons.

Children were admitted into the programme from July 12, 2010 to December 11, 2010, the last patient was discharged from the programme on December 22, 2010. Anthropometric data of all children in the programme were recorded in the study database. The initial number of children meeting the inclusion criterion (MUAC <115 mm) who were cured in the OTP was 1022. Children were classified into different categories based on admission MUAC and WHZ. Duration of treatment and percent weight gain were compared across these categories. Percent weight gain was also compared for different height categories, height being used as a proxy for age in this population where accurate ascertainment of age is difficult.

Results

Seven hundred and fifty three children were included in the analysis. Just over half (52%) of the children were female and the median age was 16 months. Eighty-eight percent of the children in the programme were aged between 6 months and 29 months. Outcomes of the children in the OTP were within SPHERE standards with proportions of cured, defaulter and deaths being 82%, 15% and 1% respectively. The remaining 2% were referred to the main district general hospital for care beyond what was available from the MSF programme.

The overall median length of stay of all children in the study was 60 days (inter-quartile range (IQR) = 43; 81). Children with lower MUAC at admission had longer durations of treatment (p,0.001 Kruskal-Wallis test), with median durations of treatment in the lowest MUAC group of 75 days (IQR = 56; 97) and highest MUAC group of 56 days (IQR = 41; 75). The overall percent weight gain of all children in the study was 21% (IQR= 14; 29). Children with low MUAC also had higher percent weight gain (p,0.001 Kruskal-Wallis test), with median percent weight gain of 37% in the lowest MUAC group (IQR =28; 47) and 17% in the highest MUAC group (IQR 12; 23).

Response to treatment was independent of height at admission (p.0.05 Kruskal-Wallis test). The majority of children in all MUAC categories gained more than 15% of their weight at admission, with the highest proportion among those with the lowest MUAC (Cochran’s test for linear trend = 64.120, p,0.001) Similar results for WHZ to those for MUAC categories on admission were found, with both duration of treatment (p,0.001 Kruskal- Wallis test) and percent weight gain (p,0.001 Kruskal- Wallis test) decreasing as WHZ categories increased.

Conclusions

This study shows that using MUAC as discharge criterion eliminates the effect of shorter treatment in most severely malnourished children and longer treatment for least severely malnourished, as observed with percent weight gain. The findings directly address the main concern that has been identified with using the current WHO recommendation of percent weight gain. The study also shows that as a result of the longer treatment, the most severely malnourished children, such as those with the lowest MUAC on admission, achieve a higher percent weight gain than the recommended 15%. Consistent results were obtained when children were classified according to their WHZ. Again the length of stay is longer and percent weight gain is higher for the most severely malnourished.

The authors suggest using MUAC as discharge criterion, instead of a uniform percent weight gain, as having a longer duration of treatment and a higher percent weight gain for the most malnourished is highly desirable.

Note that the pending WHO Nutrition Expert Advisory Group (NUGAG) guideline update on the management of SAM in infants and children (2013) recommends that percent weight gain should no longer be used as a discharge criterion from SAM treatment programmes. It also recommends that children admitted under one criterion are discharged under that same criterion, i.e. a child admitted under MUAC, is discharged under MUAC, a child admitted under WHZ is discharged under WHZ. (Eds)

¹Dale N et al (2013). Using Mid-Upper Arm Circumference to End Treatment of Severe Acute Malnutrition Leads to Higher Weight Gains in the Most Malnourished Children. PLOS ONE. Feb 2013, volume 8, Issue 2, e55404, pp 1-7

²WHO, UNICEF (2009). WHO child growth standards and the identification of severe acute malnutrition in infants and children. Joint statement by UNICEF and WHO. http://www.who.int/nutrition/publications/severemalnutrition/9789241598163_eng.pdf