Acute malnutrition affects 51 million children under the age of 5 worldwide. Malnutrition contributes to nearly half of all child deaths each year, with the forms characterized by wasting or oedema (acute malnutrition) associated with the highest risk of death.

Although acute malnutrition is a continuum condition, it is arbitrarily divided into severe and moderate acute malnutrition (SAM, MAM) which are managed separately, with programs overseen by different UN agencies, and using different protocols and products. Such separation complicates delivery of care, contributes to high default and low coverage, and creates confusion among caregivers. Often treatment is only available for SAM children resulting in lives lost and costly hospitalisation that could be averted if nutritional support were available earlier in the wasting process. If we are to reduce the health and mortality burden from malnutrition, the effectiveness and cost-effectiveness of current protocols need dramatic improvements.

The dosage of Ready to Use Therapeutic Food (RUTF) for SAM (130-200 kcal/kg/d) has not changed since introduction of out-patient protocols in the mid-2000s. Children classified as SAM in these protocols are determined by three independent criteria: the presence of nutritional oedema or MUAC < 115 mm or weight-height Z score <-3. The RUTF dosage in these protocols is paradoxical in that the absolute amount of RUTF prescribed in the initial phases of treatment is often less than that given as the child nears recovery, because the number of packets in the weekly ration is determined by weight. However, rate of weight gain (g/kg/day) is highest in the first two weeks of treatment, and then plateaus - suggesting no benefit of increased RUTF amounts in the later phases of treatment. Progressive reduction seems to be a more rational use of RUTF.

The Optimizing treatment for acute MAlnutrition (OptiMA) strategy consists in simplifying management of acute malnutrition through the use of a single anthropometric admission criterion (mid upper arm circumference [MUAC] < 125 mm or nutritional oedema) - one that best captures children's anthropometry related mortality risk- and by optimizing the use of RUTF by adapting doses to the nutritional recovery of the child. RUTF doses begin at 170 kcal/kg/d for the most severely wasted (MUAC < 115 mm or oedema) and reduce to 75 kcal/kg/d as oedema resolves and MUAC increases > 120 mm.

The investigators hypothesize that this strategy could double the number of children in care compared to current SAM programs without substantially increasing the amount of RUTF or staffing required while maintaining a recovery rate in line with current programs. OptiMA may also improve coverage and reduce the need for hospitalization through early identification of malnourished children.

The investigators propose to conduct a community-based non-inferiority clinical trial with individual randomization comparing the OptiMA strategy to the Democratic Republic of Congo standard nutritional protocol for SAM. Study children will be randomly assigned to the intervention arm or control arm - with children at MUAC < 125 mm or oedema eligible for RUTF in the intervention arm and those meeting current WHO SAM definition eligible in the control group. All participants will be followed for 9 months post-randomization to assess non-inferiority as defined by a composite of three endpoints : alive, acceptable nutritional status (MUAC ≥ 125 mm and WHZ >-3, no oedema) and no relapse to acute malnutrition for those who were treated with RUTF. The main secondary outcome will assess the non-inferiority of OptiMA RUTF dosing (170 kcal/kg/d) in children meeting current WHO SAM criteria compared to children with the same criteria in the control arm who will receive 130-200 kcal/kg/d.

The OptiMA strategy proposes a new malnutrition management approach, grounded in 3 main principles.

Firstly, the diagnosis of acute malnutrition is refined to target those at highest mortality risk within the CMAM definition of acute malnutrition (WHZ < -2 or MUAC < 125 mm or oedema), by targeting treatment to children with a MUAC < 125 mm or oedema. The simplicity of MUAC measure allows families to screen children and check for oedema at home and identify malnourished children at an earlier stage. The diagnosis is quickly confirmed by clinicians at the health center. MUAC progression is also used to monitor recovery and determine discharge thus eliminating the discrepancies that occur when both MUAC and WHZ are used to diagnose acute malnutrition.

Secondly, RUTF dosage is rationalized, and calibrated to the child's degree of wasting. The WHZ tables and dosing tables are replaced by a single table that determines the child's RUTF ration based on MUAC category and weight. Larger rations, on a per kilo basis, are given to the most severely malnourished and the ration is reduced as the child progresses to recovery.

Thirdly, supply chain is simplified to a single RUTF and data management from 2 programs are merged into one. This streamlined programme should result in better coverage, a high proportion of children detected before MUAC<115 mm, lower RUTF consumption per child and fewer acute malnutrition related hospitalisations.

Inclusion Criteria:

• Be between 6 and 59 months old;
• Meet one of the acute malnutrition criteria defined as follows: PB < 125mm or ratio Weight/Size (Z-score) <-3 (WHO standard) or Oedema of grade +, ++;
• Be resident in the health area where the active screening session takes place;
• Have the free, informed and signed consent of the child's mother or guardian.

Exclusion Criteria:

• Children with medical complication or negative appetite test or oedema (grade +++)
• Children allergic to milk or peanuts;
• Children suffering from a known chronic pathology such as sickle cell anemia, trisomy 21, congenital heart disease, or neurological condition;
• Children currently in a malnutrition programme.

The research findings will be disseminated in peer-reviewed journals, meetings and international conferences.

Individual participant data will be accessible through controlled access repositories, after deidentification (text, tables, figures, and appendices).

SAP : before end of the study on ClinicalTrials.gov Individual participant data : Beginning 6 months and ending 36 months following article publication. After 36 months the data will be available in our University's data warehouse and in co-investigators (Programme National Nutrition of DRC) data warehouse.

Study Protocol and ICF(both in french) can be shared on request Individual participant data : researchers who provide a methodologically sound proposal and whose proposed use of the data has been approved by an independent review committee