Introduction/Aim: Respiratory exacerbations in children with bronchiectasis are treated with antibiotics. While oral antibiotics are superior to placebo and recommended by guidelines to treat children with non-severe (non-hospitalized) exacerbations, not all will benefit. Therefore, we aimed to identify factors predicting those who will improve after a 14-day oral antibiotic course.

Methods: Demographic and clinical data from our two recently completed double-blind, double-dummy, randomized controlled trials were retrieved for the 202 children who received at least 14-days of oral antibiotics to treat their non-severe exacerbations. Univariable and multivariable logistic regression was used to identify factors associated with their response to antibiotics.

Results: Of the 202 children (51% males), 41% were Indigenous (Maori or Australian First Nations). Their median age was 4.2 (interquartile range 2.3–6.7) years at diagnosis of bronchiectasis. All received 14-days of amoxicillin-clavulanate or azithromycin. By Day-14, 130 (64%) children had improved according to validated cough score and clinical assessments, while 72 had not. Baseline characteristics were similar in both responder and non-responder groups. Univariable analysis found significant differences between groups for Indigenous ethnicity, number of non-hospitalized exacerbations needing antibiotics in the preceding 2-years, and number of lobes affected by bronchiectasis. Following multivariable analysis, Indigenous ethnicity (ORadjusted=4.70 95%CI 2.20–10.01), cough score at the exacerbation beginning (ORadjusted=0.58 95%CI 0.39–0.86) and number of lobes affected by bronchiectasis (ORadjusted=0.75 95%CI 0.57–0.99) were significant factors in identifying responders. Detecting a respiratory virus at the beginning of an exacerbation did not affect the response to antibiotics.

Conclusion: Among children with a non-severe bronchiectasis exacerbation, those more likely to respond to oral antibiotics were of Indigenous background, had less severe bronchiectasis as judged by a fewer number of affected lobes, and had less severe cough scores at the beginning of an exacerbation than those lacking these factors.