Identifying fibrotic interstitial lung disease risk in COPD, asthma and heart failure

Abstract

Fibrotic interstitial lung disease (fILD) is often diagnosed late and can be difficult to recognise in people with common respiratory or cardiac long-term conditions. We examined whether baseline routine blood-test profiles and leucocyte telomere length (LTL) identified groups at higher risk of subsequent hospital-recorded fILD among people with COPD, asthma or heart failure. We analysed 396 516 UK Biobank participants with complete baseline C-reactive protein, albumin, haemoglobin, platelet count, estimated glomerular filtration rate, LTL and core covariates. The primary outcome was first post-baseline hospital recording of ICD-10 J84.1; other coded ILD diagnoses and death were treated as competing events. Cause-specific Cox models assessed associations and discrimination. Risk-enrichment analyses included 53 661 participants with pre-baseline COPD, asthma or heart failure. Adding the biomarker panel improved the C-index from 0.783 to 0.803; the combined model reached 0.816. Among participants with at least two of four prespecified abnormal blood-test results and shortest-decile LTL, 10-year fILD cumulative incidence was 5.00% (14/280; 95% CI 2.50–7.50%), versus 0.43% (201/46 474; 0.38–0.49%) in the reference group. Elevated risk persisted beyond two years of follow-up. Adverse biomarker/LTL profiles were disproportionately represented among more deprived participants; fILD incidence was 0.50% versus 0.85% in the least versus most deprived quintiles, while competing mortality was 4.70% versus 10.78%. Routine blood-test profiles and LTL identified groups at increased risk of subsequent hospital-recorded fILD among people with COPD, asthma or heart failure. These findings support long-term risk enrichment and require external clinical validation before use in diagnostic pathways.