Abstract: Background: Prospective follow-up studies on children with adenovirus pneumonia after discharge are few, and there is no effective predictor of the risk factors for adenovirus pneumonia developing into post-infectious bronchiolitis obliterans (PIBO). Objective: To investigate the predictive value of the indicators during hospitalization of adenovirus pneumonia for PIBO in the future. Design: Nested case-control study. Methods: Children discharged from hospital who were diagnosed as adenovirus pneumonia from 2018 to 2019 were selected as the cohort, and whether PIBO occurred within one year after discharge was the end point. We arrange them to come to our hospital for a follow-up 2 weeks after discharge. Within 3 months we will arrange them a chest imaging examination, and follow-up will be done by telephone or in the hospital at the 12th month after discharge. The time points mentioned above are essential and other follow-up arrangement will be based on the condition of children. The symptoms and physical signs at admission, results of laboratory examination and imaging examination and treatment during hospitalization will be extracted. Main outcome measures: Risk factors for PIBO. Results: A total of 102 patients were followed up for one year, of which 51 patients had respiratory infection, 13 patients had more than 5 outpatient visits and 6 patients needed hospitalization due to respiratory infection, 43 cases were treated with oral corticosteroids and 35 cases were treated with inhaled corticosteroids. Twenty-nine cases (28.4%) were diagnosed with PIBO. Univariate analysis of the clinical data of patients in PIBO group and non-PIBO group showed that there were significant differences (P<0.05) in average age, history of allergic rhinitis, wheezing, anhelation, retraction sign of three fossae, wheezing sound, respiratory failure, the average concentration of lactate dehydrogenase, virus infection, combining two or more kinds of pathogen infection, lung parenchyma infiltration ≥3 lung lobes, lung consolidation, atelectasis, average length of hospital stay between the two groups. Multiple Logistic regression analysis showed that wheezing in the acute stage (OR=3.110, P=0.045) and more than 3 involved lung lobes (OR=4.338, P=0.014) were independent risk factors for PIBO. Conclusion: The incidence of PIBO in children with adenovirus pneumonia within 1 year after discharge from hospital was 28.4%. Wheezing in the acute stage and more than 3 involved lung lobes were independent risk factors for PIBO in children with adenovirus pneumonia.

Key words: Adenovirus pneumonia, Prospective follow-up, Postinfectious bronchiolitis obliterans, Risk factors