Development and validation of a novel clinical risk score to predict hypoxemia in children with pneumonia using the WHO PREPARE dataset

BackgroundHypoxemia predicts mortality at all levels of care, and appropriate management can reduce preventable deaths. However, pulse oximetry and oxygen therapy remain inaccessible in many primary care health facilities. We aimed to develop and validate a simple risk score comprising commonly evaluated clinical features to predict hypoxemia in 2-59-month-old children with pneumonia. MethodsData from 7 studies conducted in 5 countries from the Pneumonia Research Partnership to Assess WHO Recommendations (PREPARE) dataset were included. Readily available clinical features and demographic variables were used to develop a multivariable logistic regression model to predict hypoxemia (SpO2<90%) at presentation to care. The adjusted log coefficients were transformed to derive the PREPARE hypoxemia risk score and its diagnostic value was assessed in a held-out, temporal validation dataset. ResultsWe included 14,509 children in the analysis; 9.8% (n=2,515) were hypoxemic at presentation. The multivariable regression model to predict hypoxemia included age, sex, respiratory distress (nasal flaring, grunting and/or head nodding), lower chest indrawing, respiratory rate, body temperature and weight-for-age z-score. The model showed fair discrimination (area under the curve 0.70, 95% CI 0.67 to 0.73) and calibration in the validation dataset. The simplified PREPARE hypoxemia risk score includes 5 variables: age, respiratory distress, lower chest indrawing, respiratory rate and weight-for-age z-score. ConclusionThe PREPARE hypoxemia risk score, comprising five easily available characteristics, can be used to identify hypoxemia in children with pneumonia with a fair degree of certainty for use in health facilities without pulse oximetry. Its implementation would require careful consideration to limit inappropriate referrals on patients and the health system. Further external validation in community settings in low-and middle-income countries is required. KEY MESSAGESO_ST_ABSWhat is already known on this topicC_ST_ABSO_LIPulse oximetry is unavailable or underutilized in many resource-limited settings in low- and middle-income countries. C_LIO_LIHypoxemia is a good predictor of mortality and its early identification and further management can reduce mortality. C_LI What this study addsO_LIThe PREPARE hypoxemia risk score was developed using one of the largest and most geographically diverse datasets on childhood pneumonia to date. C_LIO_LIUsing age, lower chest indrawing, respiratory rate, respiratory distress and weight-for-age z-score to calculate the PREPARE hypoxemia risk score could help identify children with hypoxemia in settings without pulse oximeters. C_LI How this study might affect research, practice or policyO_LIThis study contributes to the important discussion on how best to identify hypoxemic children in the absence of pulse oximetry. C_LIO_LIFurther research is warranted to validate the findings in community settings C_LIO_LIOperationalizing and integrating the score within existing clinical management pathways must be tailored to the setting of implementation. C_LI