Relationship between pulmonary artery-to-aorta ratio and hospital length of stay in chronic obstructive pulmonary disease exacerbations: a retrospective cohort analysis and clinical implications

Aims: This study aims to evaluate the relationship between pulmonary artery/aorta (PA/Ao) ratio and hospital length of stay, disease severity, and clinical outcomes in patients hospitalized with acute exacerbations of chronic obstructive pulmonary disease (COPD). Methods: A retrospective analysis was conducted on 214 patients admitted with COPD exacerbation between May 2022 and February 2024. Following comprehensive exclusion criteria, 160 patients were included in the final analysis. PA/Ao ratios were measured on thoracic computed tomography images. Hospital length of stay, annual exacerbation frequency, and clinical parameters were evaluated. Statistical analysis employed log-transformation, multivariable regression, and ROC analysis. Results: Mean age was 69.4±9.2 years, with 64.4% being male. Mean PA/Ao ratio was 1.105±0.119. PA/Ao ratio showed significant positive correlation with log-transformed hospital length of stay (β=1.4132, 95% CI: 0.739-2.088, p=0.0001) and annual exacerbation frequency (r=0.296, p=0.0001). Patients with PA/Ao>1.15 had significantly longer hospital stays (7.7±8.0 vs 4.7±3.2 days, p=0.0025) and higher annual exacerbation frequency (1.98±1.28 vs 1.39±0.76, p=0.0003). Multivariable analysis identified PA/Ao ratio and serum lactate level as independent predictors of hospital length of stay (Model R²=0.247). Conclusion: PA/Ao ratio is a reliable predictor of hospital length of stay and disease severity in COPD exacerbations. This non invasive radiological parameter can be utilized in clinical risk stratification and treatment planning.