Infants and children 6–59 months of age with moderate wasting: evidence gaps identified during WHO guideline development

SUMMARY BOX.

• The 2023 WHO guideline on wasting and nutritional oedema provides the first systematically developed evidence-informed set of recommendations and good practice statements for children 6–59 months of age with moderate wasting.

• Several of the prioritised guideline questions lacked a rigorous evidence base, providing impetus for future studies specifically in children with moderate wasting.

• We identified several evidence gaps for moderate wasting, including: (1) accurate assessment of dehydration, (2) appropriate choice of rehydration fluids, (3) nutritional supplementation approaches, (4) prioritisation for specially formulated foods, (5) quantity of specially formulated foods and (6) implications of task-shifting to community health workers identifying and managing wasting.

Introduction

More than two-thirds of wasted children worldwide have moderate wasting, accounting for no less than 30 million children at any given time in 2024, most of whom reside in South Asia, SouthEast Asia and sub-Saharan Africa.¹ This population of infants and children 6–59 months old is defined by having a mid-upper-arm circumference (a measure of lean body mass) between 115 and less than 125 mm and/or a weight-for-height between 2 and 3 SDs below the median defined by the 2006 WHO Child Growth Standards.² While those with moderate wasting have a significantly lower mortality rate than those with severe wasting or nutritional oedema, their much larger population means that they still account for approximately 30%–40% of the deaths due to wasting.³

The spectrum of care for moderately wasted children has varied widely across varying contexts, ranging from only counselling about healthy diets and medical care to dietary supplementation with specially formulated foods (SFFs) for all moderately wasted children. Guidelines for moderate wasting must balance financial and human resource costs, commodity costs, complete community coverage, competing health priorities including the management of severe wasting and the potential negative consequences of universal supplementation with SFF.

The 2023 WHO guideline on wasting and nutritional oedema

Although at least two prior WHO consultations have addressed the issue of moderate wasting among children 6–59 months of age,^{4 5} much of the practice regarding nutritional supplementation has developed relatively organically through innovations developed and tested by practitioners in the field.6,8 While prior WHO guidance recommended that not all children with moderate wasting needed supplementary foods,⁹ there were no specific recommendations on which specific children require supplementary foods, which foods to use or how much supplementation to provide. Wide variability exists in several additional aspects of the management of moderate wasting, including issues as fundamental as which children in which locations are prioritised for certain interventions.

The 2023 WHO guideline on the prevention and management of wasting and nutritional oedema (acute malnutrition) in infants and children under 5 years¹⁰ includes the first comprehensive recommendations and good practice statements (GPSs) for moderate wasting developed systematically using WHO standards and methods, based on the Grading of Recommendations, Assessment, Development and Evaluations approach.¹¹ The guideline as a whole takes a broad view of wasting as a continuum and many of the recommendations and GPSs reasonably apply to all children with wasting.¹²

The guideline questions that were prioritised by the Guideline Development Group (GDG) for moderate wasting primarily focused on dietary management, with four recommendations ultimately made by the GDG around the use of SFFs for some children with moderate wasting. The complete list of recommendations and GPSs for moderate wasting is found in table 1 and reflects many of the priority questions that have stemmed from various interest holders, including researchers, policy-makers and front-line clinicians.

Table 1. Overview of recommendations and good practice statements (GPS) for infants and children 6–59 months of age with moderate wasting.

Recommendation or GPS number	Subject	Strength	Certainty
B6	Classification of hydration status	N/A (GPS)
B8	Use of ORS for rehydration	Conditional	Very low
B11	Nutrient-dense diets for recovery and normal growth	N/A (GPS)
B12	Comprehensive assessment for predisposing medical and psychosocial problems	N/A (GPS)
B13	Individual child and social factors for prioritisation of SFFs	Strong	Moderate
B14	Contextual factors for prioritisation of SFFs	Strong	Moderate
B15	Preferred types of SFFs to be provided	Conditional	Low
B16	Quantity of SFFs to be provided	Conditional	Very low
B17	Identification and management by community health workers	Conditional	Very low
C1	Post-exit interventions for caregivers	N/A (GPS)
C2	Psychosocial stimulation for children after exit from care	Conditional	Low

GPS, good practice statement; N/A, not applicable; ORS, oral rehydration solution; SFFs, specially formulated foods.

The GDG emphasised the importance of nutrient-dense home diets for nutritional recovery, sustained growth and optimal health as well as assessments to identify medical and psychosocial barriers to recovery through two GPSs (B11 and B12). What this assessment specifically involves, how it would be carried out and by whom, and what should be done to address any challenges identified will vary across different contexts, as little evidence exists to guide these issues. Similarly, another GPS recommends continued support for caregivers of wasted children after exit from their nutritional supplementation programme (C1). What this support should entail—for example, caregiver support and counselling or water, sanitation and hygiene interventions—will again vary across contexts and it is unknown which interventions will prove most effective in helping children achieve optimal growth and health.

In addition to these ‘implementation gaps’ that will need to be addressed by local programmers and policymakers, several additional evidence gaps related to the diagnosis and management of moderate wasting are highlighted in this commentary, some of which parallel the identified gaps among children with severe wasting.¹³ We believe that identifying and understanding these gaps will be useful to researchers and policy-makers interested in advancing care for children with moderate wasting, as well as being of interest to front-line clinicians seeking to better understand the rationale behind the care being provided.

Evidence gaps

Accurate assessment of dehydration

Perhaps the most commonly encountered medical comorbidity seen with wasting is dehydration, usually due to gastroenteritis or nutrient malabsorption, and is associated with increased morbidity and mortality.¹⁴ Given the overlap in clinical signs and symptoms (eg, sunken eyes) between moderate wasting and dehydration, it is often challenging for front-line clinicians to differentiate between the two.¹⁵ The evidence base for making an optimal diagnosis of dehydration in this population remains weak. Nevertheless, the GDG emphasised the need to still make every effort to accurately assess hydration status so that appropriate rehydration therapies are provided, as outlined in a GPS (B6).

Appropriate choice of rehydration fluids

The GDG made a conditional recommendation based on very low certainty evidence that WHO low-osmolarity oral rehydration solution should be the oral rehydration fluid of choice in this population (B8). This is in contrast to the conditional recommendation that outlines a preference for ReSoMal (where available) for children with dehydration and severe wasting or oedematous malnutrition (B7). To a large degree, this was a pragmatic recommendation considering the availability of different formulations in most settings. At the time of 2023 guideline development, rigorous intervention trials to inform the choice of rehydration formula did not exist, although preliminary results from the important new GastroSAM study¹⁶ have shown that the two oral rehydration fluids are indeed likely equivalent.

Nutritional supplementation approaches

The available evidence regarding the nutritional supplementation of moderate wasting was relatively weak, whose underlying pathophysiology¹⁷ and optimal nutritional management^{8 18} are still poorly defined. Important outstanding questions include:

• Defining the optimal composition for nutritional supplementation and quantity for children with moderate wasting.

• The optimal rate of weight gain during supplementation.

• Understanding the impact of improved breastfeeding, home foods and other non-SFF interventions.

The acceptability and feasibility of the various approaches recommended also remain to be investigated, especially as interventions are rolled out on a wider scale.

While evidence was specifically sought for non-dietary interventions and for dietary interventions other than SFFs, insufficient evidence was identified for the GDG to make recommendations beyond those involving SFF. Given the relatively high cost of SFFs for health systems that aim to manage large numbers of children with moderate wasting, the lack of evidence on nutritional approaches other than SFFs (eg, breastfeeding, home foods) represents one of the major gaps in our understanding of how to support these vulnerable children.

Prioritisation for SFFs

A strong recommendation based on moderate certainty evidence (B13) prioritises SFFs over counselling alone for moderately wasted children who are at risk of poor outcomes. Given the very large number of moderately wasted children in many settings with limited resources, the guideline specifies individual child and social factors that could be used to prioritise which children are selected for supplementation.^{10 19} Further research to help refine risk factors for poor health outcomes in these children was identified as a major priority, as it would have both biomedical and practical implications. It also remains unknown whether this list of individual child risk factors for poor outcomes corresponds with those children who would benefit most from SFF—or whether these children would remain at highest risk no matter the supplementation given. Research gaps thus include:

• Evaluating the response to nutritional supplementation.

• Outcomes among children who are not supplemented.

• The cost and cost-effectiveness of SFFs and other interventions.

• An evaluation of potential equity and acceptability concerns with this prioritisation approach.

• An assessment of the feasibility of providing SFF to all infants and children with moderate wasting.

Health workers and programmers would likely also benefit from evidence regarding how to judge the success of non-SFF interventions, for example, how much weight gain might be expected or how long a health worker should follow a child with counselling alone before supplementing with SFFs.

Similar to the child and social factors identified in B13, strong recommendation B14 provides contextual characteristics/circumstances that could be used to prioritise supplementation with SFFs to children with moderate wasting. In high-risk contexts (where there is a recent or ongoing humanitarian crisis), defined by characteristics/circumstances such as high rates of food insecurity, all moderately wasted children should be considered for SFFs. Evidence gaps with this context-level prioritisation recommendation parallel those of the individual-level prioritisation, in addition to the need to clarify and quantify what threshold(s) of community-wide food insecurity should trigger universal supplementation for moderate wasting.

Quantity of SFFs

Recommendations on the types (B15) and quantity of SFFs (B16) for moderate wasting were also developed by the GDG. These recommendations were both formulated as conditional, mainly due to these being highly context-specific in terms of resources and impacts on equity, acceptability and low or very low certainty evidence around outcomes. Sufficient evidence on longer-term outcomes such as sustained recovery was also lacking. Recommendation B16 regarding the quantity of supplementation to provide was largely based on empirical evidence of resting energy expenditure as well as the energy believed to be needed for catch-up growth. Indirect evidence and numerous empirical assumptions were used to estimate likely energy requirements for children with moderate wasting and related comorbidities. This issue remains a major research need, highlighting our relative lack of knowledge about energy and nutrient needs for anthropometric recovery (not to mention physiological recovery and sustenance of recovery in the long term) and the optimal rate of weight gain. As another example, the use of ready-to-use therapeutic food (RUTF) has not been extensively studied head-to-head against RUSF or other SFF products for moderate wasting, except in one completed²⁰ and one ongoing trial,¹⁹ and thus deserves evaluation in operational settings.

Implications of task-shifting to community health workers identifying and managing wasting

Community health workers (CHWs) in many settings identify and manage children with a number of medical conditions²¹ including wasting, potentially improving coverage and early diagnosis. In recognition of this, the GDG made a conditional recommendation for CHWs to be empowered and supported to carry out this important work (B17). The clinical outcomes and cost-effectiveness of CHWs carrying out this work at various points in the care pathway (diagnosis, management, follow-up, etc) should be studied. An important aspect would be to study the unintended consequences that may occur as these extra tasks are added to their already heavy workload. It is anticipated that CHW-led care could lead to earlier diagnosis of wasting, greater coverage and a higher likelihood of completing therapy since care is brought closer to the child’s home. This would have to be balanced with other factors, including their ability to recognise children that need a higher level of clinical care. The importance of sufficient training, supervision, monitoring and resources required for CHW-led care was included in this recommendation by the GDG. However, specifics were not detailed and would depend on local context. Since the publication of the guideline, some work has indeed already been published demonstrating the cost-effectiveness of CHW-led care.²²

Conclusions

The 2023 WHO guideline¹⁰ provides several evidence-informed recommendations and GPSs relating to the diagnosis, management and postdischarge care of children with moderate wasting. Overall, relatively little rigorous data were available to answer the prioritised guideline questions, other than for the issues related to provision of SFFs. The evidence base should be improved and refined by well-designed randomised controlled trials, especially those that take into consideration cost, feasibility and local contextual variation. As research in severe wasting has a longer and more mature history, some of the recommendations that were originally intended to apply only to severely wasted children are likely amenable to extrapolation to moderately wasted children, especially as management programmes move towards streamlining and integrating care for all wasted children. However, moderately wasted children deserve rigorous inquiry into the effectiveness of any such extrapolations once implemented in both research and operational contexts.

The authors alone are responsible for the views expressed in this article and they do not necessarily represent the views, decisions, or policies of the institutions with which they are affiliated.

Data availability statement

No data are available.