Low-dose heparin sodium as a protective factor against bronchiolitis obliterans formation after adenovirus infection.

Background: Adenovirus (ADV) pneumonia in children is a significant contributor to the occurrence of post-infectious bronchiolitis obliterans (BO). Heparin sodium has known anti-inflammatory, immunomodulatory, and tissue repair properties. However, its role in treating BO after ADV infection remains unclear.

Methods: A retrospective analysis was conducted on 793 children diagnosed with ADV pneumonia and hospitalized in the southern region from January 2019 to December 2019. Among them, 307 cases were classified as single ADV pneumonia. We utilized directed acyclic graphs to analyze the causal relationships between various variables, which further helped us identify the independent and confounding variables for constructing our regression model. Propensity score matching (PSM) was also employed to control for confounding variables that could not be intervened in this study, ensuring baseline level equilibrium and correction. We utilized univariate logistic regression analysis to explore the factors influencing BO development after ADV pneumonia.

Results: Among the 793 children diagnosed with ADV pneumonia, 86 cases (10.84%) progressed to BO. The proportion of heparin use was higher in the non-BO group than in the BO group after PSM. The univariate regression analysis revealed that acute respiratory failure, neurological involvement and fibrinogen (FIB) were risk factors for the development of BO in ADV pneumonia cases (OR > 1,  < 0.05), but low-dose heparin sodium treatment and hemoglobin (OR < 1,  < 0.05) exhibited protective effects against BO formation. Among the 307 children with single ADV pneumonia (excluding confounding factors), 33 cases (10.75%) developed BO. The univariate regression analysis further indicated that fever duration, acute respiratory failure and FIB were risk factors for the development of BO in single ADV pneumonia (OR > 1,  < 0.05), while low-dose heparin sodium treatment (OR < 1,  < 0.05) was protective against BO formation after a single ADV pneumonia.

Conclusion: Low-dose heparin sodium treatment may be a protective factor against the development of BO after ADV pneumonia infection.