Challenges in the classification of fibrotic ILD

Area of Science:

• Pulmonology
• Radiology
• Pathology

Background:

• Idiopathic interstitial pneumonias (IIPs) are classified as major, rare, or unclassifiable.
• Idiopathic pulmonary fibrosis (IPF) is a major IIP with recognized diagnostic criteria and therapeutic targets.
• A significant percentage of interstitial lung disease (ILD) patients remain unclassifiable due to incomplete or conflicting data.

Purpose of the Study:

• To discuss the characteristics and management of unclassifiable ILD.
• To highlight the utility of the ILD-GAP index in risk-stratifying unclassifiable ILD patients.
• To explore future diagnostic avenues for unclassifiable ILD.

Main Methods:

• Review of current international guidelines for IIPs.
• Analysis of patient demographics and survival data for unclassifiable ILD.
• Validation of the ILD-GAP index and Disease Behaviour Classification (DBC) in unclassifiable ILD.

Main Results:

• Unclassifiable ILD patients are similar in age to IPF patients and older than those with connective tissue disorders.
• Survival in unclassifiable ILD is intermediate between IPF and non-IPF ILD.
• The ILD-GAP index is validated for risk stratification in unclassifiable ILD, offering prognostic information.

Conclusions:

• Unclassifiable ILD presents a management challenge with no single recommended treatment.
• The ILD-GAP index provides valuable prognostic information for unclassifiable ILD.
• Future advancements in diagnostic tools, such as protein biomarkers, may improve therapeutic decision-making for unclassifiable ILD.