Sex-specific aspects in an unclassified population of patients with interstitial lung disease (ILD) undergoing transbronchial cryobiopsy (TCB)

<bold>Introduction:</bold> Sex-specific aspects of idiopathic pulmonary fibrosis (IPF) are well-documented. However, these have not been investigated in the assessment of previously undiagnosed ILDs. <bold>Methods:</bold> Patients with ILD who underwent BAL, TCB and, if necessary, surgical lung biopsy (SLB) at the Thoraxklinik Heidelberg from 11/17-12/2021 were analysed. Along with clinical parameters CT biomarkers were analyzed. These included visual analysis and fully automated segmentation using the YACTA QCT software tool with emphysema index (El% -950 HU) and 80th and 40th percentile of lung density, representative of fibrosis and ground-glass opacity (GGO), respectively. Final diagnoses were made by multidisciplinary discussion (MDD). <bold>Results:</bold> The study analysed data from 402 patients, comprising 248 males and 154 females with an average age of 68±12 years. QCT imaging did not reveal sex differences. GGO were equally prevalent in both sexes.SLB was administered to 18 patients (4.5%) in addition to TCB. A final diagnosis was possible in over 90% of cases, if including unclassifiable ILD. There were sex differences in diagnoses: ILD with a known cause was diagnosed in 12% of men and 15% of women, IIP in 59% of men and 38% of women, granulomatous ILD in 25% of men and 37% of women, and other forms in 2% of men and 4% of women (p<0.001). In women, NSIP and unclassifiable ILD were the most commonly diagnosed IIP, each accounting for 32% of cases, whereas in men, IPF was the most commonly diagnosed IIP, accounting for 37% of cases (p=0.008). <bold>Conclusion:</bold> There were significant sex differences in diagnoses in this heterogeneous patient population.