To evaluate the validity of the Responses to Illness Severity Quantification (RISQ) score to discriminate illness severity and transitions between levels of care during hospitalization.

A prospective observational study conducted in Maiduguri, Nigeria, enrolled inpatients aged 1-59 months with severe acute malnutrition. The primary outcome was the RISQ score associated with the patient state. Heart and respiratory rate, oxygen saturation, respiratory effort, oxygen use, temperature, and level of consciousness are summed to calculate the RISQ score. Five states were defined by levels of care and hospital discharge outcome. The states were classified hierarchically, reflecting illness severity: hospital mortality was the most severe state, then intensive care unit (ICU), care in the stabilization phase (SP), care in the rehabilitation phase (RP), and lowest severity, survival at hospital discharge. A multistate statistical model examined performance of the RISQ score in predicting clinical states and transitions.

Of 903 children enrolled (mean age, 14.6 months), 63 (7%) died. Mean RISQ scores during care in each phase were 3.5 (n = 2265) in the ICU, 1.7 (n = 6301) in the SP, and 1.5 (n = 2377) in the RP. Mean scores and HRs for a 3-point change in score at transitions: ICU to death, 6.9 (HR, 1.80); SP to ICU, 2.8 (HR, 2.00); ICU to SP, 2.0 (HR, 0.5); and RP to discharge, 1.4 (HR, 0.91).

The RISQ score can discriminate between points of escalation or de-escalation of care and reflects illness severity in hospitalized children with severe acute malnutrition. Evaluation of clinical implementation and demonstration of benefit will be important before widespread adoption.