Rate of progression of lung function impairment in α1-antitrypsin deficiency

The aim of the present study was to identify alpha(1)-antitrypsin (alpha(1)-AT)-deficient patients who had rapidly progressive disease. PiZ patients (n=101) underwent annual lung function measurements over a 3-yr period, and the results were related to factors that may influence decline. The mean annual decline in forced expiratory volume in 1 s (FEV1) was 49.9 mL The greatest FEV1 decline occurred in the moderate severity group (FEV1 50-80% of the predicted value), with a mean annual decline of 90.1 mL compared with 8.1 mL in the very severe group (FEV1 < 30% pred). However, annual decline in transfer coefficient of the lung for carbon monoxide (Kco) was greatest in the severe and very severe groups. When the whole group was divided into tertiles of FEV1 decline, the fast tertile compared with the slow tertile had more patients with bronchodilator reversibility (BDR) (73 versus 41%; p=0.010), more males (79 versus 56%; p=0.048) and lower body mass index (BMI) (24.0 versus 26.1; p=0.042). Logistic regression analyses confirmed that FEV1 decline was independently associated with BMI, BDR, exacerbation rate and high physical component 36-item short-form health survey scores. In PiZ alpha(1)-AT-deficient patients, FEV1 decline was greatest in moderate disease, unlike Kco decline, which was greatest in severe disease. The FEV1 decline showed associations with BDR, BMI, sex and exacerbation rate.