Discussion
idiopathic interstitial pneumonia, ILD
IDIOPATHIC INTERSTITIAL PNEUMONIA
In this analysis of ILA reported in a prevalence LDCT screening round, 2.5% of cases had mention of ILA in their CT report and 0.8% of cases were deemed clinically significant needing referral to the ILD service. Of those cases referred, IPF was the most common specific diagnosis (14 cases comprising 26% of referred cases with a final diagnosis), with 25 patients having unclassifiable idiopathic interstitial pneumonia (comprising 47% of referred cases with a final diagnosis). In total, 10 patients received pharmacotherapy (7 with antifibrotics and 3 with prednisolone) comprising 18% of all referred cases and 0.15% of all screening participants.In our cohort, participants with ILD were older than those without ILD, in keeping with the previous reports.The prevalence of ILA reported in this series is lower than that reported elsewhere (2.5% here compared with 8%–10% in other screening seriesThe current study is the largest to date to report eventual ILD diagnoses and the subsequent clinical outcomes following assessment. Two smaller studies from the UK have reported very different prevalence rates for new diagnoses of ILD across two rounds of LDCT screening. Only 1 study noted 28 new ILD diagnoses from 1853 screening participants (1.5%) with 0.6% commenced on pharmacotherapy.Other studies that have assessed changes in ILA over a 2-year interval reported 33% improving, 47% remaining stable and 20% progressing.