Prevalence and radiological outcomes of lung nodules in alpha 1-antitrypsin deficiency

Pulmonary nodules are a frequent incidental finding on computed tomography (CT) imaging. This study sought to investigate the prevalence and radiological outcomes of lung nodules in patients with alpha 1-antitrypsin deficiency (AATD), and determine any association with systemic inflammation and disease progression. A retrospective study was conducted using thoracic CT imaging from 494 patients on the AATD U.K. registry. Patients were categorised according to radiological and clinical outcome, and comparisons made with respect to baseline demographics, lung function and high-sensitivity CRP (hs-CRP). Sixty-four patients (13%) had a nodule present on baseline imaging, and in total 132 patients (27%) had a nodule on at least one scan, of which 2 were malignant. The presence of a lung nodule was associated with significantly lower baseline percent predicted forced expiratory volume in 1 s (FEV1 % predicted) (p = 0.037) and percent predicted transfer coefficient of the lung for carbon monoxide (Kco % predicted, p = 0.001). Patients with self-resolving nodules had higher baseline hs-CRP concentrations (p < 0.01) and more rapid decline in Kco (p = 0.03) compared to patients in whom no nodules were observed. The prevalence of 'incidental' pulmonary nodules on CT imaging in patients with AATD was 13%. Self-resolving pulmonary nodules were associated with increased systemic inflammation and progression of emphysema and may therefore reflect an important component of emphysema pathogenesis or a marker of emphysema.