Lung transplantation and survival outcomes in patients with oxygen-dependent COPD with regard to their alpha-1 antitrypsin deficiency status

Abstract

Background: Individuals with severe alpha-1 antitrypsin deficiency (AATD) have an increased risk of developing COPD. However, outcomes during long-term oxygen therapy (LTOT) in patients with severe AATD and hypoxemia are unknown. Patients and methods: This was a prospective, population-based, consecutive cohort study of patients on LTOT due to COPD in the period from January 1, 1987, to June 30, 2015, in the Swedish National Registry for Respiratory Failure (Swedevox). Severe AATD was identified using the Swedish AATD registry and confirmed by isoelectric focusing. Data on lung transplantation (LTx) were obtained from the two lung transplantation centers in Sweden. Mortality and causes of death were assessed based on the National Causes of Death Registry and analyzed using multivariable Cox regression. Results: A total of 14,644 patients who started LTOT due to COPD were included in this study. No patient was lost to follow up. Patients with AATD were younger, included more males and more never smokers, and had fewer comorbidities. During a median follow-up of 1.6 years (interquartile range [IQR], 2.7) on LTOT, patients without severe AATD had a higher mortality, hazard ratio [HR] 1.53 (95% CI, 1.24–1.88), adjusting for age, sex, smoking status, body mass index, performance status, level of hypoxemia, and comorbidities. Cardiovascular deaths were increased. A higher proportion of AATD patients underwent LTx, 53 (19%) vs 118 (1%). Survival after LTx was similar for AATD and non-AATD patients and was predicted by age. Conclusion: In oxygen-dependent COPD, patients with severe AATD have a longer survival time on LTOT, but they have a similar prognosis after lung transplantation compared with patients without AATD.