Interstitial lung abnormalities with a diagnosis of idiopathic pulmonary fibrosis

Abstract

<b>Background:</b> Attention has been focused on identifying cases with a progressive phenotype in interstitial lung abnormalities (ILA). Some ILA cases may be followed up as they are, some may be diagnosed with interstitial lung disease (ILD) as a result of work-up, including a surgical lung biopsy. <b>Aims:</b> To evaluate if the cases of&nbsp; idiopathic pulmonary fibrosis (IPF) with definition of ILA (ILA-IPF) differed from those of IPF without ILA (non-ILA-IPF). <b>Methods:</b> Of the patients diagnosed with IPF from January 2008 to July 2015, 149 ILA-IPF cases and 120 non-ILA-IPF cases were examined for various variables including disease progression and prognosis.&nbsp; ILA is defined based on the incidental identification of CT abnormality that are potentially compatible with ILD without previous clinical suspicion of ILD (Lancet Respir Med 2020; 8: 726–37). <b>Results:</b> In patients’ background at diagnosis of the two groups, significant differences were observed in age, PaO₂, pulmonary function test, and exercise tolerance. Median overall survival was significantly longer in the ILA-IPF group (78.9 months vs 52.2 months, p&lt;0.01). There was no significant difference in the annual FVC decline (ILA-IPF, -121.3 mL / year vs non-ILA-IPF, -58.9 mL/year, p=0.16). Univariate analysis revealed ILA, age, honeycomb, %FVC, %D_LCO were significant prognostic factors. The prognosis adjusted by gender, age, FVC, and D_LCO was not significantly different between ILA-IPF and non-ILA-IPF. (hazard ratio 0.79, 95% CI 0.56-1.11, p=0.18). <b>Conclusion:</b> No significant difference was observed in disease progression and prognosis between ILA-IPF and non-ILA-IPF. Early diagnosis of IPF in ILA patients is crucial.