Risk factors for recurrent wheezing after bronchiolitis in infants:2-year follow up in China
Abstract Background: Infants with bronchiolitis have an increased risk of developing recurrent wheezing and asthma. However, the risk factors for the development of recurrent wheezing after bronchiolitis remains controversial.Objective: To investigate the incidence of post-bronchiolitis recurrent wheezing and associated risk factors.Methods: Infants with bronchiolitis were enrolled from November 2016 through March 2017. Nasopharyngeal aspirates were obtained for detection of respiratory viruses which were analyzed by reverse transcriptase polymerase chain reaction (RT-PCR) and direct immunofluorescent assay. Serum cytokines including TSLP, IL2, IL13, TIMP-1, MMP-9, IL33, IL5, IL4, IL25, TNF- α and MIP-1α were measured by flow cytometry. Patients were followed every 3 months for a duration of 2 years by telephone or at outpatient appointments.Results: We enrolled 89 infants, of which 81 patients were successfully followed up. In total, 22.2% of patients experienced recurrent wheezing episodes. The proportion of patients with history of eczema, systemic glucocorticoid use and patients with moderate-to-severe disease were significantly higher in the recurrent wheezing group than the non-recurrent wheezing group (83.3% vs 52.4%; 66.7% vs 36.5%; 61.1% vs 33.3%, respectively, all P<0.05); There were no significant differences between patients with and without recurrent wheezing episodes in the levels of TSLP, IL2, IL13, TIMP-1, MMP-9, IL33, IL5, IL4, IL25, TNF- α and MIP-1α (P>0.05). Logistic regression analysis showed that history of eczema was an independent risk factor for post-bronchiolitis recurrent wheezing (odds ratio [OR]=5.622; 95% confidence interval [CI], 1.3–24.9; P=0.023).Conclusion: The incidence of recurrent wheezing among infants after contracting bronchiolitis was 22.2% during a 2-year follow-up. History of eczema was the only independent risk factor identified and no correlation was found between the specific virus and disease severity in children with post-bronchiolitis recurrent wheezing.