Sex-specific aspects in a population of patients undergoing evaluation for interstitial lung disease with transbronchial cryobiopsy

There are well-documented differences in idiopathic pulmonary fibrosis (IPF) between sexes. The sex-specific prevalence of interstitial lung disease (ILD) subtypes in patients who require a full diagnostic work-up, including transbronchial cryobiopsy (TCB), after initial multidisciplinary discussion (MDD) is still unknown. Retrospective analysis of sex dispareties in patients with ILD who received an interdisciplinary indication for lung biopsy and underwent bronchoalveolar lavage, TCB and, if necessary, surgical lung biopsy at our ILD centre in Heidelberg between 11/17 and 12/21. The analysis included clinical parameters, visual assessment of computed tomography (CT), automated histogram analyses of lung density by validated software and final MDD-ILD classifications. A total of 402 patients (248 men, 154 women; mean age 68 ± 12 years) were analysed. Smoking behaviour was similar between the sexes, but women were more exposed to environmental factors, whereas men were more exposed to occupational factors. Women had higher rates of thyroid disease (29.9% vs. 12.5%; p < 0.001) and extrathoracic malignancies (16.2% vs. 9.3%; p = 0.041), but lower rates of coronary heart disease (7.1% vs. 19.8%; p < 0.001), stroke (1.3% vs. 6.5%; p = 0.014) and sleep apnoea (5.8% vs. 17.7%; p < 0.001). There were no sex differences regarding CT lung density. On visual inspection, women were less likely to have reticular opacities (65% vs. 76%; p = 0.017) and features of usual interstitial pneumonia (17% vs. 34%; p < 0.001). Among final diagnoses, hypersensitivity pneumonitis was more common in women (34.4%) compared to men (21.8%; p = 0.007). In contrast, IPF was more common in men (22.6%) than in women (7.1%; p < 0.001), and unclassifiable interstitial lung disease was also more frequent in men (21.8%) compared to women (6.5%; p < 0.001). This study highlights significant sex-based differences in the prevalence and characteristics of ILD requiring comprehensive diagnostic work-up. These findings underscore the importance of considering sex-specific factors in the diagnosis and management of ILD.