Nutritional treatment of children 6-59 months with severely low weight-for-age z-score: a study protocol for a 3-arm randomized controlled trial

BACKGROUND

Admission criteria that treat children with low mid-upper-arm circumference (MUAC), and low weight-for-height z-score (WHZ) are not aligned with the evidence on which children are at risk of mortality. An analysis of community-based cohort data from Senegal found that a combination of weight-for-age (WAZ) and MUAC criteria identified all children at risk of near-term death associated with severe anthropometric deficits. This study will address whether children with WAZ <-3 but MUAC ≥125 mm benefit from therapeutic feeding with ready-to-use therapeutic foods (RUTF) and whether a simplified protocol is non-inferior to the weight-based standard protocol.

METHODS

This is a prospective individually randomized controlled 3-arm trial conducted in the Nara health district in Mali. Children aged 6-59 months presenting with MUAC ≥125 mm and WAZ <-3 will be randomized to (1) control group receiving no treatment, (2) simplified treatment receiving 1 sachet of RUTF daily until WAZ ≥-3 for 2 visits, (3) standard treatment receiving RUTF according to WHZ category: (a) WHZ <-3 receive 200 kcal/kg/day until WHZ ≥-2 for 2 visits, (b) WHZ ≥-3 but <-2 receive 1 sachet daily until WHZ ≥-2 for 2 visits or (c) WHZ ≥-2 receive no treatment. All children will be followed up first fortnightly for 12 weeks and then monthly until 6 months post-enrolment. The primary endpoint will be measured at 2 months with the primary outcome being WAZ as a continuous measure. Other outcomes include other anthropometric measurements and a secondary endpoint will be observed at 6 months. A total of 1397 children will be recruited including 209 in the control and 594 in both the simplified and standard arms. The sample size should enable us to conclude on the superiority of the simplified treatment compared to no treatment and on the non-inferiority of the simplified treatment versus standard treatment with a margin of non-inferiority of 0.2 WAZ.

DISCUSSION

This trial aims to generate new evidence on the benefit of treating children with WAZ <-3 but MUAC ≥125 mm in order to guide the choice of admission criteria to malnutrition treatment and build evidence on the most efficient treatment protocol.

TRIAL REGISTRATION

This trial was registered at ClinicalTrials.gov: NCT05248516 on February 21, 2022.

Severely malnourished children with a low weight-for-height have similar mortality to those with a low mid-upper-arm-circumference: II. Systematic literature review and meta-analysis

BACKGROUND

The WHO recommended criteria for diagnosis of sever acute malnutrition (SAM) are weight-for-height/length Z-score (WHZ) of <- 3Z of the WHO₂₀₀₆ standards, a mid-upper-arm circumference (MUAC) of < 115 mm, nutritional oedema or any combination of these parameters. A move to eliminate WHZ as a diagnostic criterion has been made on the assertion that children with a low WHZ are healthy, that MUAC is a "superior" prognostic indicator of mortality and that adding WHZ to the assessment does not improve the prediction of death. Our objective was to examine the literature comparing the risk of death of SAM children admitted by WHZ or MUAC criteria.

METHODS

We conducted a systematic search for reports which examined the relationship of WHZ and MUAC to mortality for children less than 60 months. The WHZ, MUAC, outcome and programmatic variables were abstracted from the reports and examined. Individual study's case fatality rates were compared by chi-squared analysis and random effects meta-analyses for combined data.

RESULTS

Twenty-one datasets were reviewed. All the patient studies had an ascertainment bias. Most were inadequate because they had insufficient deaths, used obsolete standards, combined oedematous and non-oedematous subjects, did not report the proportion of children with both deficits or the deaths occurred remotely after anthropometry. The meta-analyses showed that the mortality risks for children who have SAM by MUAC < 115 mm only and those with SAM by WHZ < -3Z only are not different.

CONCLUSIONS

As the diagnostic criteria identify different children, this analysis does not support the abandonment of WHZ as an important independent diagnostic criterion for the diagnosis of SAM. Failure to identify such children will result in their being denied treatment and unnecessary deaths from SAM.

Severely malnourished children with a low weight-for-height have a higher mortality than those with a low mid-upper-arm-circumference: III. Effect of case-load on malnutrition related mortality- policy implications

BACKGROUND

Severe acute malnutrition (SAM) is diagnosed when the weight-for-height Z-score (WHZ) is <-3Z of the WHO2006 standards, or a mid-upper-arm circumference (MUAC) of < 115 mm or there is nutritional oedema. Although there has been a move to eliminate WHZ as a diagnostic criterion we have shown that children with a low WHZ have at least as high a mortality risk as those with a low MUAC. Here we take the estimated case fatality rates and published case-loads to estimate the proportion of total SAM related deaths occurring in children that would be excluded from treatment with a MUAC-only policy.

METHODS

The effect of varying case-load and mortality rates on the proportion of all deaths that would occur in admitted children was examined. We used the same calculations to estimate the proportion of all SAM-related deaths that would be excluded with a MUAC-only policy in 48 countries with very different relative case loads for SAM by only MUAC, only WHZ and children with both deficits. The case fatality rates (CFR) are taken from simulations, empirical data and the literature.

RESULTS

The relative number of cases of SAM by MUAC alone, WHZ alone and those with both criteria have a dominant effect on the proportion of all SAM-related deaths that would occur in children excluded from treatment by a MUAC-only program. Many countries, particularly in the Sahel, West Africa and South East Asia would fail to identify the majority of SAM-related deaths if a MUAC only program were to be implemented. Globally, the estimated minimum number of deaths that would occur among children excluded from treatment in our analyses is 300,000 annually.

CONCLUSIONS

The number, proportion or attributable fraction of children excluded from treatment with any change of current policy are the correct indicators to guide policy change. CRFs alone should not be used to guide policy in choosing whether or not to drop WHZ as a diagnostic for SAM. All the criteria for diagnosis of malnutrition need to be retained. It is critical that methods are found to identify those children with a low WHZ, but not a low MUAC, in the community so that they will not remain undetected.

Severely malnourished children with a low weight-for-height have a higher mortality than those with a low mid-upper-arm-circumference: I. Empirical data demonstrates Simpson's paradox

BACKGROUND

According to WHO childhood severe acute malnutrition (SAM) is diagnosed when the weight-for-height Z-score (WHZ) is <-3Z of the WHO2006 standards, the mid-upper-arm circumference (MUAC) is < 115 mm, there is nutritional oedema or any combination of these parameters. Recently there has been a move to eliminate WHZ as a diagnostic criterion on the assertion that children meeting the WHZ criterion are healthy, that MUAC is universally a superior prognostic indicator of mortality and that adding WHZ to the assessment does not improve the prediction; these assertions have lead to a controversy concerning the role of WHZ in the diagnosis of SAM.

METHODS

We examined the mortality experience of 76,887 6-60 month old severely malnourished children admitted for treatment to in-patient, out-patient or supplementary feeding facilities in 18 African countries, of whom 3588 died. They were divided into 7 different diagnostic categories for analysis of mortality rates by comparison of case fatality rates, relative risk of death and meta-analysis of the difference between children admitted using MUAC and WHZ criteria.

RESULTS

The mortality rate was higher in those children fulfilling the WHO2006 WHZ criterion than the MUAC criterion. This was the case for younger as well as older children and in all regions except for marasmic children in East Africa. Those fulfilling both criteria had a higher mortality. Nutritional oedema increased the risk of death. Having oedema and a low WHZ dramatically increased the mortality rate whereas addition of the MUAC criterion to either oedema-alone or oedema plus a low WHZ did not further increase the mortality rate. The data were subject to extreme confounding giving Simpson's paradox, which reversed the apparent mortality rates when children fulfilling both WHZ and MUAC criteria were included in the estimation of the risk of death of those fulfilling either the WHZ or MUAC criteria alone.

CONCLUSIONS

Children with a low WHZ, but a MUAC above the SAM cut-off point are at high risk of death. Simpson's paradox due to confounding from oedema and mathematical coupling may make previous statistical analyses which failed to distinguish the diagnostic groups an unreliable guide to policy. WHZ needs to be retained as an independent criterion for diagnosis of SAM and methods found to identify those children with a low WHZ, but not a low MUAC, in the community.

Mid-Upper-Arm Circumference and Arm-to-Height Ratio to Identify Obesity in School-Age Children

BACKGROUND

In resource-poor settings, anthropometric parameters are evaluated as potential alternatives to the body mass index (BMI) for detecting overweight and obesity in children. To this end, the mid-upper-arm circumference (MUAC) and the mid-upper-arm circumference-to-height ratio (AHtR) were evaluated as proxies to BMI in Thai school-age children.

STUDY DESIGN

An observational, cross-sectional study was performed on school-aged children.

PARTICIPANTS

Children in grades 1 through 6 at all public elementary schools in the Ongkharak district, Nakhon Nayok, Thailand during May and June 2013 were included. This is a rural district with low per capita income.

METHODS

Weight, height, and MUAC were measured in school-age children and analyzed to identify optimal cut-off values for MUAC and AHtR for detection of overweight and obesity in comparison to BMI. Receiver operating characteristic (ROC) curve analysis determined the validity of MUAC and AHtR use.

RESULTS

Data from 3,618 children, aged 6.0-12.99 years, were analyzed. MUAC correlated with age and height (P < 0.001), but especially with body weight (r = 0.888 to 0.914) and BMI (r = 0.859 to 0.908) in both genders, while AHtR correlated with body weight and BMI (P < 0.001), but not with age. Cut-off values of MUAC for obesity diagnosis ranged from 18.9 to 25.5 cm for boys and from 19.8 to 25.4 cm for girls. Accuracy was excellent for both boys (AUC = 0.952-0.991) and girls (AUC = 0.917-0.990). Cut-off of MUAC for overweight diagnosis ranged from 17.2 to 22.4 cm for boys (AUC = 0.883-0.965) and from 18.0 to 23.2 cm for girls (AUC = 0.905-0.931). AHtR cut-off values for obesity and overweight diagnosis at 0.16 and 0.145, respectively, were determined with excellent diagnostic accuracy (AUC ranged from 0.920 to 0.975).

CONCLUSION

MUAC and AHtR were reliable tools to detect overweight and obesity in Thai school-age children. Cut-off points for MUAC were age and gender specific, while AHtR at 0.16 and 0.145 were the optimal values for both genders, independent of age. These anthropometric measurements showed excellent accuracy in predicting overweight and obesity with high specificity and sensitivity.