Abstract:

Objective To investigate the risk factors of recurrent respiratory infections in children with refractory asthma，and to establish and verity a nomogram model. Methods A total of 415 children with refractory asthma in acute exacerbation admitted to Nanjing University of Traditional Chinese Medicine Affiliated Hospital，Jiangsu Provincial Hospital of Traditional Chinese Medicine from January 2021 to December 2023 were enrolled and classified into recurrent respiratory infection group（76 cases）and non-recurrent respiratory infection group（339 cases）. Binary Logistic regression analysis were used to screen the risk factors of recurrent respiratory infections in children with refractory asthma. The nomogram model was constructed by rms packape of R software. The clinical applicability and diagnostic efficiency of the model were verified by receiver operating characteristic （ROC） curve，calibration curve，decision curve analysis （DCA） and clinical impact curve. Results The white blood cell （WBC） count，C-reactive protein （CRP），IgE，CD4+/CD8+ ratio，the number of asthma attacks≥3 times and the proportion of rhinitis or sinusitis in recurrent respiratory infection group were higher than those in non-recurrent respiratory infection group （P<0.05）. The platelet（PLT）count，CD4+T cell percentage （CD4+%） and CD8+T cell percentage （CD8+%） were lower than those in non-recurrent respiratory infection group （P<0.05）. Increased IgE，decreased PLT count，decreased CD4+%，combined rhinitis or sinusitis and asthma attacks≥3 times were independent risk factors for recurrent respiratory infection in children with refractory asthma （P<0.05）. Based on the above factors，the nomogram model determined that the area under curve （AUC） of recurrent respiratory infection in children with refractory asthma was 0.909，and the predicted probability of the model was consistent with the actual probability. When the threshold probability value was 0.02-0.91，the clinical net benefit was >0，and the predicted results of the model are basically consistent with the actual results. Conclusions PLT count，IgE，CD4+，whether to combine rhinitis or sinusitis and the number of asthma attacks are related to recurrent respiratory infection in children with refractory asthma. The nomogram model constructed based on the above factors can provide a reference for the identification of high-risk children and has certain clinical applicability.

Key words: Recurrent respiratory infection, Refractory asthma, Nomogram