Prevalence, Clinical Features, and Outcomes of Young Patients with Idiopathic Pulmonary Fibrosis

Introduction: Idiopathic pulmonary fibrosis (IPF) can occur at any age; however, studies on younger IPF patients are scarce because it primarily affects the elderly. This study aimed to investigate the clinical features and outcomes of younger IPF patients.

Methods: We analyzed the National Korean Health Insurance Review and Assessment Service (HIRA) database from 2015 to 2021. Patients with IPF were identified using the International Classification of Diseases 10th Revision (ICD-10) codes and the Rare Intractable Diseases codes and were categorized into three age groups: <50, ≥50 and <65, and ≥65 years. The risk of acute exacerbation (AE) and mortality was analyzed.

Results: Among 4,243 patients with IPF, 91 were under 50. These younger patients, who were predominantly female, exhibited less comorbidities and received more systemic steroids, whereas older group received more pirfenidone. Although AE risk increased with age, it was not statistically significant. Mortality and lung transplantation risks increased notably with age from the <50 group to the ≥50 and <65 group (hazard ratio [HR]: 1.52, 95% confidence interval [CI]: 0.93-2.49) and the ≥65 group (HR: 2.44, 95% CI: 1.51-3.93). These risks were influenced by factors such as age, comorbidities, previous AEs, and steroid use. Conversely, pirfenidone treatment reduced the risk.

Conclusion: While younger IPF patients had a lower risk of mortality and lung transplantation, with no significant differences in the risk of AEs, they were less likely to receive antifibrotic therapy and more often treated with steroids, which may affect outcomes. Early, targeted treatment strategies, including antifibrotic use, are crucial for improving their prognosis.