1 antitrypsin deficiency prevalence in patients with Chronic Obstructive Airways Disease: a screening program in Nord Sardinia

1 antitrypsin deficiency (AATD) is a rare condition with low or undetectable levels of 1 antitrypsin (AAT) that predisposes mainly to pulmonary and hepatic diseases. The diagnosis delay negatively influences the quality of life and the prognosis but, even if recommended by different International Health Societies, screening programs among the at risk subjects are still inadequate. The project has the aim to describe, in at risk group, the AATD incidence, the allelic prevalence and its clinical and genetic characteristics in order to improve the disease knowledge and awareness. We made an observational screening study in subjects aged more than 18 years old affected by COPD, asthma, bronchiectasis and pneumothorax followed in outpatients clinic of the Respiratory Disease Department of the Sassari University in Sardina from 2017 to 2019. An AAT serum dosage was performed in all the subjects and if the AAT was beneath the cut off of 128 mg/dl, hematic samples were genotyped. 469 subjects were enrolled, 57% males, with a mean age of 67.96 ± 14.24 years old. 61% were active or former smokers, with a mean tobacco consumption of 29.56 ± 35.45 pack-years. 62.5% were affected by COPD, followed by asthma (23.7%) and emphysema (19.2%). The mean AAT value observed was 155.83 ± 46,68. 71 patients (15%) had an AAT value lower than the chosen cut off. 38 of them (53,5%) showed a mono or bi allelic mutations. The more frequent mutations observed were heterozygosis MMMalton (39%) and the heterozygosis MS (37%). MMalton is the more carried mutated allele (18 subjects) with an estimated prevalence in our population of 3,84%. The AATD prevalence observed in our affected population, is 8.32%, significantly higher than the general population. Diagnose AATD promptly is always essential because of the chance to modify its evolution, but speaking of respiratory patients this became mandatory for the clinical, ethical but also the socioeconomic impact.