Performance of five risk stratification tools for paediatric pneumonia against WHO scores using data from the PediCAP trial in sub-Saharan Africa

Abstract

Background Risk stratification tools for childhood pneumonia have been proposed to improve identification of children at highest risk of death, particularly in low-resource settings. However, their added value over the WHO Integrated Management of Childhood Illness (IMCI) criteria and danger signs remains uncertain. Methods We conducted a secondary analysis of a multi-country randomised controlled trial of children without HIV hospitalised with pneumonia in Mozambique, South Africa, Uganda, Zambia, and Zimbabwe. We evaluated the performance of five published risk scores alongside WHO IMCI severity classification and danger signs. Discrimination for (1) in-hospital mortality, (2) 28-day mortality, and (3) 28-day readmission or death was assessed using area under the receiver operating characteristic curve (AUC). Comparative performance and clinical utility were examined. Results Of the 1010 participants, 18 (1.8%) died in hospital, 22 (2.2%) died in hospital or in the 7 days post-discharge, and 63 (6.2%) died or were readmitted by day 28. Univariate case-fatality rates were highest for variables associated with malnutrition, convulsions, and hypoxaemia. All risk scores demonstrated moderate discrimination for in-hospital and in-hospital+7-day mortality (AUC range approximately 0.75–0.84), with no meaningful differences between models, and performed similarly to the WHO danger signs and IMCI severity classification. In contrast, all approaches performed poorly in predicting 28-day readmission or death (AUC approximately 0.54–0.58). No risk score consistently outperformed simple clinical criteria. Conclusions In this multi-country dataset, we found no evidence that published paediatric pneumonia risk scores meaningfully outperform WHO IMCI-based clinical assessment for predicting mortality. The relatively small number of mortality events limits precision, and modest differences cannot be excluded. These findings suggest that, in low-resource settings, strengthening implementation of existing WHO clinical criteria may be more effective than adopting more complex prediction tools. What is already known on this topic Several clinical risk scores have been developed to predict mortality in childhood pneumonia, with some validation studies in low-resource settings, although head-to-head comparisons across multiple risk stratification tools and settings are limited. WHO IMCI criteria are widely known and commonly used in many low-resource settings, but their comparative performance against newer risk stratification tools and for post-discharge outcomes is uncertain. What this study adds In a multicountry African cohort, published paediatric pneumonia risk scores showed similar performance to the WHO IMCI criteria for predicting mortality. No consistent advantage of more complex tools over the WHO IMCI criteria was observed. All approaches showed limited ability to predict 28-day readmission or death. How this study might affect research, practice, or policy These findings suggest that improving implementation of the WHO IMCI may be more important than introducing more complex risk scores in low-resource settings. The limited performance of all approaches for post-discharge outcomes highlights the need to consider additional factors beyond admission clinical severity.