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

Abstract

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.