Real-world care patterns and specialist encounters of patients with systemic autoimmune rheumatic disease-related interstitial lung disease in the United States: a retrospective administrative claims database analysis

Rheumatology (Oxford). 2025 Apr 23:keaf200. doi: 10.1093/rheumatology/keaf200. Online ahead of print.

ABSTRACT

OBJECTIVES: We aimed to describe the demographics, clinical characteristics, and care patterns of patients with systemic autoimmune rheumatic diseases (SARD) prior to their interstitial lung disease (ILD) diagnosis.

METHODS: We conducted a retrospective cohort study using claims data from Healthcare Integrated Research Database (2006-2023). Adults diagnosed with SARD-ILD were identified, with the earliest ILD diagnosis date designated as the index date. A minimum of 36 months of continuous enrolment before the index date was required. All measures were analyzed descriptively. For a subset of patients with respiratory symptoms before ILD diagnosis, the association between type of specialist encounter and time from symptom onset to SARD-ILD diagnosis was assessed using a Cox proportional hazards model.

RESULTS: The study included 2,526 patients with SARD-ILD. Mean age was 62.6 years and 75.4% were female. Before ILD diagnosis, 61.8% of patients had at least one all-cause hospitalization. Diagnostic tests including chest computed tomography (CT), high-resolution CT, and pulmonary function tests (PFT) were used in 80.1%, 59.0%, and 60.3% of patients, respectively. Among the subgroup, patients who saw a pulmonologist within 90 days of initial respiratory symptom onset were 18% more likely to be diagnosed with ILD compared with those who did not (Hazard ratio: 1.18, 95% confidence interval 1.03-1.35; p= 0.017).

CONCLUSION: The study highlights the complex diagnostic journey of patients with SARD-ILD. Findings suggest a multidisciplinary approach involving pulmonologists and rheumatologists could enable timely ILD diagnosis and should be considered for more effective diagnosis and management of SARD-ILD.

PMID:40268746 | DOI:10.1093/rheumatology/keaf200