BACKGROUND Acute respiratory illnesses cause substantial morbidity worldwide. Cough is a common symptom in these childhood respiratory illnesses but there is currently no large cohort data on whether various cough… Click to show full abstract
BACKGROUND Acute respiratory illnesses cause substantial morbidity worldwide. Cough is a common symptom in these childhood respiratory illnesses but there is currently no large cohort data on whether various cough characteristics can differentiate between these aetiologies. RESEARCH QUESTION Can various clinically-based cough characteristics (frequency [day-time/ night-time], the sound itself, or type [wet/dry]) be used to differentiate common aetiologies (asthma, bronchiolitis, pneumonia, other acute respiratory infections) of acute cough in children? STUDY DESIGN AND METHODS Between 2017-2019, children aged 2-weeks to ≤16-years hospitalised with asthma, bronchiolitis, pneumonia, other acute respiratory infections, or controls were enrolled. Spontaneous coughs were digitally recorded over 24-hours except for the controls, who provided three voluntary coughs. Coughs were extracted and frequency defined (coughs/hour). Cough sounds and type were assessed independently by two observers blinded to the clinical data. Cough scored by a respiratory specialist was compared to discharge diagnosis using agreement (Cohen's kappa coefficient [қ]), sensitivity, and specificity. Caregiver reported cough scores were related with objective cough frequency using Spearman's coefficient (rs). RESULTS A cohort of 148 children (n=118 with respiratory illnesses, n=30 controls), median age=2.0 years (interquartile range 0.7, 3.9), 58% males, and 50% First Nations children were enrolled. In those with respiratory illnesses, caregiver reported cough scores and wet cough (range 42-63%) was similar. Overall agreement in diagnosis between the respiratory specialist and discharge diagnosis was slight (қ=0.13, 95%CI 0.03, 0.22). Among diagnoses, specificity (8-74%) and sensitivity (53-100%) varied. Inter-rater agreement in cough type (wet/dry) between blinded observers was almost perfect (қ=0.89, 95%CI 0.81, 0.97). Objective cough frequency was significantly correlated with reported cough scores using visual analogue scale (rs=0.43, bias-corrected 95%CI 0.25, 0.56) and verbal categorical description day-time score (rs=0.39, bias-corrected 95%CI 0.22, 0.54). INTERPRETATION Cough characteristics alone are not distinct enough to accurately differentiate between common acute respiratory illnesses in children.
               
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