Survival in the Swedish cohort with alpha-1-antitrypsin deficiency, up to the age of 43-45 years

Background: Alpha-1-antitrypsin deficiency (AATD) is a hereditary disorder. AATD is a known risk factor for the development of emphysema and liver disease. A cohort of severe (PiZZ) and moderate (PiSZ) AAT-deficient newborn infants was identified by the Swedish national neonatal AAT screening in 1972-1974 and has been followed up since birth. Our aim was to study survival in this cohort up to 43-45 years of age in comparison with the general Swedish population. Methods: Data from 127 PiZZ, 2 PiZnull, 54 PiSZ, and 1 PiSnull subjects, who were identified by the neonatal screening in 1972-1974, were included in the study. To compare death rates in the PiZZ and PiSZ individuals with the general Swedish population, a standardized mortality ratio (SMR) was calculated as the ratio of observed to expected deaths. Results: Seven PiZZ subjects died during the follow-up, to be compared with an expected 3.66 deaths for the general population, giving an SMR of 1.91 (95% CI 0.77-3.94). Four PiSZ subjects died compared to an expected 1.53 deaths, giving an SMR of 2.61 (95% CI 0.71-6.71). The cumulative probability of survival up to the age of 45 years was 94% (95% CI 90%-98%) for the study population. Six deaths occurred before the age of 8 years. Conclusion: Up to 43-45 years of age, there was no difference in survival between PiZZ and PiSZ individuals in comparison with the Swedish general population. The majority of deaths occurred during childhood.