Cluster randomised trial of the implementation of the Responses to Illness Severity Quantification (RISQ) system in children with acute malnutrition 6 to 59 months of age in Ngouri, Chad: the CRIMSON trial protocol

Background

The Responses to Illness Severity Quantification (RISQ) System is a clinical decision support tool designed for humanitarian contexts. It combines four elements: a validated seven-item illness severity score, age-specific forms, recommendations tailored to illness severity, and guidance for implementation. The recommendations, developed by experienced humanitarian clinicians, cover patient monitoring, secondary reviews, admission decisions, and transfers. The RISQ System is intended to support, not replace, existing clinical practice. The Crimson Study aims to measure the effect of introducing RISQ on child mortality and care processes in a nutrition programme.

Methods

The study is a cluster randomised trial comparing RISQ with standard care across 34 health centres in Ngouri district, Chad. Eligible participants are children aged 6–59 months with acute malnutrition (MUAC <125 mm and/or oedema) enrolled in the Ministry of Health/ALIMA OptiMA programme. Centres will be randomised 1:1 to standard care or RISQ. The primary outcome is mortality up to 60 days after enrolment or programme discharge. The trial includes a 14-month baseline phase followed by a 14-month intervention phase. With 20,000 children enrolled, the study is powered to detect a 0.5% absolute reduction in mortality, analysed using Bayesian logistic regression.

Discussion

This trial will assess whether the RISQ System reduces mortality and strengthens decision making in malnutrition care. By improving accuracy in hospitalisation decisions, the tool has the potential to lower child mortality by up to 30% in low-resource nutrition programmes.

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