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Background: Patients with fibrosing interstitial lung diseases (F-ILDs) are at risk of developing progressive pulmonary fibrosis, associated with worsening of symptoms, declining lung function and early mortality. Timely identification of patients with F-ILD is critical for improving patient outcomes through early access to appropriate treatments. There is limited data on time to diagnosis in patients with F-ILD.
Objectives: The objective of this study was to assess time from first respiratory symptom to diagnosis of F-ILD and describe clinical characteristics of patients with early versus delayed diagnosis of F-ILD.
Methods: This is a retrospective cohort study of adult patients diagnosed with F-ILD using the US Optum ® Clinformatics database. Patients with F-ILD were identified between 01/01/2018 and 31/12/2021 via a validated algorithm comprising of diagnosis codes specific to lung fibrosis, underlying ILD disease, and pulmonary function tests or chest imaging. Patients were required to have continuous enrolment for at least 3 years prior to F-ILD diagnosis (baseline period). The first symptom was defined as the first occurrence of dyspnoea, cough, shortness of breath or sleep disturbance in the baseline period. Early and delayed diagnosis were defined as ≤6 months and >6 months between first symptom and F-ILD diagnosis, respectively. Demographic and clinical characteristics by early versus delayed were compared using standardised mean difference (SMD).
Results: The study included 38,022 patients with F-ILD. Median age at index was 76.0 (interquartile range, IQR: 70.0-82.0) years; 19,885 (52.3%) were women and 27,293 (71.8%) were White. Of those with recorded symptoms (n=35,353), the median time from symptom onset to F-ILD index was 28.5 (IQR: 16.4 – 33.9) months. A total of 4,747 (13.4%) F-ILD patients were diagnosed within 6 months of symptom onset. There was no difference in age (SMD: 0.11), sex (SMD: 0.35) or race (SMD: White -0.05; Asian -0.34; Black/African American – 0.08) of patients with early versus delayed diagnosis. A selection of clinical characteristics that were more prevalent in patients with delayed diagnosis include: pulmonary arterial hypertension (1.7 vs 0.5%), chronic obstructive pulmonary disease (43.1% vs 26.0%), depressive disorder (26.3% vs 14.2%), gastroesophageal reflux disease (38.0% vs 22.5%), asthma (17.0% vs 8.5%), and congestive heart failure (25.1% vs 14.2%).
Conclusion: The majority (86.6%) of F-ILD patients experienced delayed diagnosis (>6 months after onset of symptoms). Chronic comorbidities including cardiovascular, respiratory, gastrointestinal and mental health disorders were more prevalent in patients with delayed diagnosis. Further research is needed on determinants of diagnostic delays to enable early identification of F-ILD patients and to assess the impact of these delays in diagnosis on future clinical and economic outcomes.
REFERENCES: NIL.
Acknowledgements: This study was supported and funded by Boehringer Ingelheim International GmbH.
Disclosure of Interests: Pratik Pimple Employee of Boehringer Ingelheim, Maria Cristina Penaloza Ramos Employee of Boehringer Ingelheim, Martin Lavallee Employee of Boehringer Ingelheim, Ajit A Londhe Employee of Boehringer Ingelheim, Steady Chasimpha Paid consultant for Boehringer Ingelheim, Sue Langham Paid consultant for Boehringer Ingelheim, Anne L Wilson Paid consultant for Boehringer Ingelheim, Carmen Ng Employee of Boehringer Ingelheim, Yanni Fan Employee of Boehringer Ingelheim, Madhu Kanakapura Employee of Boehringer Ingelheim, Andrew H Limper Received consultancy fees from Boehringer Ingelheim.
© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license (