CAP is the most common infectious disease during childhood,Nevertheless, no validated nomogram models exist to predict the risk of PO caused by SCAP.Although vaccination has significantly reduced the incidence and mortality of severe pneumonia in children in recent years, this initiative is yet to become universal, and pneumonia remains the leading cause of death among children aged between 1 month and 5 years 11–12. There are limitations in the evaluation and prognosis of children's condition relying on a single symptom and sign, but there is no precise and practical comprehensive evaluation standard at present and there are no adequate tools to predict their outcomes13. Therefore, in this study, univariate analysis and multivariate logistic regression analysis were used to identify the risk factors for PO, and a PO-predictive nomogram was constructed to comprehensively and accurately estimate the risk of PO for each patient with SCAP.
This study showed that SCAP mainly occurred in infancy, and Walker CLF et al. have also shown that the occurrence of and death from SCAP in children were most common in children aged less than 1 year 12. This is related to the imperfect anatomical and physiological characteristics and functional development of the respiratory system in this age group, which leads to easy invasion by pathogens. The results of this study showed that the gender composition of children had a preponderance for males than females, with a male:female ratio of 1.5:1, and previous studies have shown similar results12, 14.
This study showed that comorbidity and IMV were independent risk factors for PO in children with SCAP. Congenital heart disease has been found to be the most common co-morbidity in children with SCAP, and children with congenital heart disease may have an increase in pulmonary blood volume, which can lead to repeated infection of respiratory tract15, hospitalization, and repeated antimicrobial application, which leads to infection with multiple drug-resistant bacteria, and all of these factors may be contribute to a reduction in treatment efficacy. Previous studies have confirmed that basic cardiopulmonary diseases and other systemic diseases, including congenital heart disease, bronchopulmonary dysplasia, cystic fibrosis, and asthma, can induce and aggravate pneumonia16–17. Koh JWJC et al. have also shown that co-morbidity was an independent risk factor for PO in patients with SCAP(14). On the other hand, children who require IMV often develop severe hypoxia and illness, while children with SCAP undergoing IMV may experience some complications, such as ventilator-associated pneumonia (VAP), pulmonary barotrauma, laryngeal edema, airway injury, and pneumothorax18, and these complications can affect the prognosis in severe cases.
In conclusion, our study suggested that active treatment of the co-morbidity in children with SCAP should be carried out to reduce its impact on the course of pneumonia and the prognosis of children. In children requiring IMV, great attention should be paid to the prevention of the above-mentioned complications. For example, the movement of endotracheal intubation should be as gentle as possible, and the assistance of experienced physicians should be requested whenever necessary. In children who have received IMV treatment, more careful care, such as manual lung inflation, vibration expectoration and early functional exercise19, should be given to prevent the occurrence of IMV complications.
In order to accurately predict the risk of PO in children with SCAP, the study visualized the results of multivariate logistic regression analysis in a simplified and convenient nomogram model, which is convenient for clinical workers to comprehensively evaluate the disease of the children according to various clinical indicators in the treatment process. Based on AUC and calibration curve evaluation,the nomogram model showed good accuracy and consistency, which can effectively help predict the development of PO in children due to SCAP as early as possible and take strong preventive or therapeutic measures, which can improve the outcomes of patients due to SCAP to a certain extent.
However, our study still had some limitations. First, this retrospective study was based on reviewing medical records data from a single institution and with a small simple size. Second, bootstrap repeated sampling was used to verify the model in the study, and thus, it is necessary to validate the results from other centers. In addition, a prospective multi-center in-sample study is required to further confirm the reliability of the nomogram.