Building a Prediction Model for Radiographically Confirmed Pneumonia in Peruvian Children

Abstract

BackgroundCommunity-acquired pneumonia remains the leading cause of death in children worldwide, and current diagnostic guidelines in resource-poor settings are neither sensitive nor specific. We sought to determine the ability to correctly diagnose radiographically confirmed clinical pneumonia when diagnostics tools were added to clinical signs and symptoms in a cohort of children with acute respiratory illnesses in Peru.MethodsChildren < 5 years of age with an acute respiratory illness presenting to a tertiary hospital in Lima, Peru, were enrolled. The ability to predict radiographically confirmed clinical pneumonia was assessed using logistic regression under four additive scenarios: clinical signs and symptoms only, addition of lung auscultation, addition of oxyhemoglobin saturation (Spo2), and addition of lung ultrasound.ResultsOf 832 children (mean age, 21.3 months; 59% boys), 453 (54.6%) had clinical pneumonia and 221 (26.6%) were radiographically confirmed. Children with radiographically confirmed clinical pneumonia had lower average Spo2 than those without (95.9% vs 96.6%, respectively; P < .01). The ability to correctly identify radiographically confirmed clinical pneumonia using clinical signs and symptoms was limited (area under the curve [AUC] = 0.62; 95% CI, 0.58-0.67) with a sensitivity of 66% (95% CI, 59%-73%) and specificity of 53% (95% CI, 49%-57%). The addition of lung auscultation improved classification (AUC = 0.73; 95% CI, 0.69-0.77) with a sensitivity of 75% (95% CI, 69%-81%) and specificity of 53% (95% CI, 49%-57%) for the presence of crackles. In contrast, the addition of Spo2 did not improve classification (AUC = 0.73; 95% CI, 0.69-0.77) with a sensitivity of 40% (95% CI, 33%-47%) and specificity of 72% (95% CI, 68%-75%) for an Spo2 ≤ 92%. Adding consolidation on lung ultrasound was associated with the largest improvement in classification (AUC = 0.85; 95% CI, 0.82-0.89) with a sensitivity of 55% (95% CI, 48%-63%) and specificity of 95% (95% CI, 93%-97%).ConclusionsThe addition of lung ultrasound and auscultation to clinical signs and symptoms improved the ability to correctly classify radiographically confirmed clinical pneumonia. Implementation of auscultation- and ultrasound-based diagnostic tools can be considered to improve diagnostic yield of pneumonia in resource-poor settings.

Challenges in the diagnosis of paediatric pneumonia in intervention field trials: recommendations from a pneumonia field trial working group

“…90 Some of the limitations met when using only one ancillary approach to identify pneumonia can be lessened with the combination of multiple diagnostic tests. For example, one study 59 found that the area under the receiver operating characteristic curve (a summary measure of the accuracy of a quantitative diagnostic test) increased from 0·62, when using the WHO pneumonia criterion, to 0·85 when using a combination of signs and symptoms, auscultation, pulse oximetry, and lung ultrasound. 59 Investigators should also carefully select thresholds for diagnostic procedures.…”

“…For example, one study 59 found that the area under the receiver operating characteristic curve (a summary measure of the accuracy of a quantitative diagnostic test) increased from 0·62, when using the WHO pneumonia criterion, to 0·85 when using a combination of signs and symptoms, auscultation, pulse oximetry, and lung ultrasound. 59 Investigators should also carefully select thresholds for diagnostic procedures. The cutoff points used by WHO for both respiratory rate and oxyhaemoglobin saturation have been criticised for not having an appropriate agespecificity or altitude-specificity.…”

“…Lung auscultation is a diagnostic procedure that could improve diagnostic specificity. 59 Inspiratory lung crackles are believed to represent the equalisation of distal airway pressures caused by the abrupt opening of collapsed alveoli and adjacent airways. 60 The likelihood of radiographic pneumonia increases in the presence of crackles on auscultation.…”

Training and standardization of general practitioners in the use of lung ultrasound for the diagnosis of pediatric pneumonia

“…Our research group found that it was feasible to introduce LUS for the identification of consolidation in pediatric pneumonia to physicians with limited ultrasound experience in the low‐resource settings of Nepal and Peru . Indeed, a recent analysis from our group found that among a cohort of Peruvian children seeking care for an acute respiratory illness, LUS had the greatest ability to predict radiographically‐confirmed pneumonia when compared with clinical signs and symptoms, pulse oximetry and chest auscultation …”

“…11 Indeed, a recent analysis from our group found that among a cohort of Peruvian children seeking care for an acute respiratory illness, LUS had the greatest ability to predict radiographically-confirmed pneumonia when compared with clinical signs and symptoms, pulse oximetry and chest auscultation. 12 A limitation to the use of LUS in epidemiological studies of pediatric pneumonia is a lack of consensus on what constitutes a primary endpoint pneumonia and an optimal scanning protocol 13-15 ; unlike CXR, which has well-established criteria for training and interpretation. 16 Studies have shown that LUS may be able to replace CXR as an imaging modality for pneumonia 17 with no change in clinical outcomes.…”