S14 Absence of CT imaging in AEILD admissions associated with higher mortality risk

White, L and Shaw, J and Powell, B and Kyi, NM and Huang, R and Hardy, E and Hughes, G and Tilakaratne, D and Hayton, C and Raj, T and Truong, V and Ismail, N and Khanijoun, N and Sou, A and Man Kwong, G Ng and Gadoud, A and Gatheral, T (2025) S14 Absence of CT imaging in AEILD admissions associated with higher mortality risk. Thorax, 80 (Suppl.). A16.1-A16. ISSN 0040-6376

Abstract

Background Acute exacerbations of interstitial lung disease (AEILD) are devastating events with high mortality. A definite AEILD is defined by <30-day deterioration in respiratory symptoms, not due to cardiac, thrombotic or pneumothorax causes, with new bilateral ground-glass changes on a background of ILD.1 High-resolution CT imaging is central to this definition, yet its use during AEILD admissions is variable and understudied. We evaluated whether CT imaging during AEILD admission was associated with survival and differences in care. Methods We conducted a multicentre retrospective observational study of ICD-10-coded primary ILD admissions in patients ≥18 years, across 11 NHS hospitals in North West England between 01.01.2017 and 31.12.2019. AEILD events were identified using clinical criteria via manual review. Events were grouped by whether thoracic CT imaging was performed. Primary outcome was time to death from admission commencement. Results 511 AEILD admissions were identified; 192 (37.6%) had CT imaging. Median survival was significantly longer in the CT group (144 vs. 100 days; p=0.027); mean survival was also higher (493.8 vs. 394.7 days). Respiratory team involvement was more frequent in the CT group (79.2% vs. 62.1%; p<0.001), as was high-dose intravenous methylprednisolone use (11.5% vs. 3.8%; p=0.002). Mean length of stay was longer in the CT group (11.5 vs. 6.6 days; p<0.001), while palliative care input was more common in the non-CT group (20.1% vs. 14.6%). Baseline demographics, lung function and comorbidity scores were similar. Discussion CT imaging during AEILD admissions was associated with improved survival, more respiratory specialist input and greater use of high-dose steroid treatment. This may reflect diagnostic certainty influencing care escalation, or that in the non-CT group some patients were too unstable to undergo imaging and further management. Conclusion Hospitalised AEILD patients face high mortality. Our findings suggest variation in CT use may influence care and outcomes. Further prospective studies are needed to determine whether CT imaging contributes directly to improved survival or is a proxy for more intensive management.