Abstract / Summary
Background 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. Methods 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. Results 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%. Conclusions 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.