Clinical characteristics and risk factors for poor prognosis of RSV lower respiratory tract infection: a two-center study

Objective Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infection (LRTI) in children under five years of age. In this study, we investigated the value of simple and readily available clinical indicators in predicting poor prognosis in children with RSV-LRTI. Methods This was a retrospective cohort study of children with RSV-LRTI admitted to Children’s Hospital of Nanjing Medical University (April 2023–May 2024) and Gaoyou People’s Hospital (December 2024–June 2025). Demographic and clinical data were collected from patient records, and patients were stratified based on three adverse prognostic events: admission to Intensive Care Unit (ICU), prolonged hospital stay, and severe pneumonia. Results A total of 257 eligible children were enrolled, of whom 254 (98.8%) exhibited cough, 144 (56.0%) presented with wheezing and 194 (75.4%) developed febrile symptoms. 220 (85.6%) cases of RSV-LRTI occurred in winter and spring, with a higher proportion of cases occurring in infants under 1 year of age. A higher respiratory rate at admission was independently associated with ICU admission (Firth regression: OR 1.132, both P < 0.05), though this finding was limited by the small number of ICU cases. The presence of three concave sign was independently associated with prolonged hospital stay (OR 5.242, 95% CI 1.360-19.951, P = 0.017). Procalcitonin (PCT) was an independent risk factor for severe pneumonia (OR 1.616, 95% CI 1.074–2.837, P = 0.020). Conclusion Higher respiratory rate at admission was independently associated with ICU admission, and the presence of three concave sign was independently associated with prolonged hospital stay. PCT was an independent risk factor for severe pneumonia. These simple clinical indicators facilitate early identification of children at risk of adverse outcomes.