Alpha-1 antitrypsin deficiency prevalence in COPD patients in a specialized hospital in Buenos Aires, Argentina

Abstract

Background: Alpha-1 antitrypsin (AAT) deficiency is a rare hereditary disorder. Underdiagnosis in Argentina is huge due to a lack of knowledge of the disorder with frequent undertesting. Aims: Estimate prevalence of patients with alpha-1 antitrypsin deficiency (AATD) in patients with COPD in a specialized hospital. Methods: Transversal study including 727 patients (age 30-70) with COPD (Gold classification) between 2013 and 2015. Demographics, smoking and family respiratory history characteristics were evaluated. AAT was measured in dry blood spot (DBS) by nephelometry. Cut-off validated was 1.80 mg/dL on DBS corresponding 100 mg/dL AAT on serum. In patients under cut-off, genotypification was made, using real time PCR with primers and hibridation sondes specifically for S and Z mutations with melting curve. Statistical analysis was made with PAWS statistics 18 © software. Results: We found male predominance (61,1%), 32.7% of active smokers, mean 50 paq-year.32.9% had family history of respiratory disease. Mean alpha-1 antitrypsin was 1,88 mg/dl,42% of total under cut-off,genotypifications was made. Deficient patients ZZ=11 (1.51%), SZ=2 (0.27%) while 6.05 % were carriers SS=4 (0.55%), MZ=12 (1.65%), MS=28 (3.85%). Conclusions: This study estimates the prevalence of AATD among patients with COPD with an easy method at the time of pulmonary function testing. Results in a total of 727 elegible patients, carriers (MZ, SS, MS) were 6.05% while deficient patients (ZZ, SZ) were 1.78%.