Detection and early referral of patients with interstitial lung abnormalities: an expert survey initiative

Background: Interstitial lung abnormalities (ILA) may represent undiagnosed early-stage or subclinical interstitial lung disease (ILD). ILA are often observed incidentally in patients who subsequently develop clinically overt ILD. There is limited information on consensus definitions for, and the appropriate evaluation of, ILA; early recognition of patients with ILD remains challenging, yet critically important. Expert consensus could inform early recognition and referral. Research question: Can consensus-based expert recommendations be identified to guide clinicians in the recognition, referral and follow-up of patients with, or at risk of developing, early ILDs? Study design and methods: Pulmonologists and radiologists with expertise in ILD participated in two iterative rounds of surveys. Surveys aimed to establish consensus regarding ILA reporting, identification of patients with ILA, and identification of populations that might benefit from screening for ILD. Recommended referral criteria and follow-up processes were also addressed. Threshold for consensus was defined a priori as ≥ 75% agreement or disagreement. Results: Fifty-five experts were invited and 44 participated , reaching consensus on 39/85 questions. The following clinically important statements achieved consensus: honeycombing and traction bronchiectasis or bronchiolectasis indicate potentially progressive ILD; honeycombing detected during lung cancer screening should be reported as potentially significant (e.g. with LUNG-Rads "S" modifier), recommending referral to a pulmonologist in the radiology report; high-resolution computed tomography and full pulmonary function tests should be ordered if non-dependent subpleural reticulation, traction bronchiectasis, honeycombing, centrilobular ground-glass nodules or patchy ground-glass opacity are observed on computed tomography; patients with honeycombing or traction bronchiectasis should be referred to a pulmonologist irrespective of forced vital capacity and diffusion capacity values; and patients with systemic sclerosis should be screened with pulmonary function tests for early-stage ILD. Interpretation: Guidance for identifying clinically relevant ILA, subsequent referral and follow-up was established. These results lay foundations for developing practical guidance on managing patients with ILA.