The prevalence of diagnosed α1-antitrypsin deficiency and its comorbidities: results from a large population-based database

An Epidemiological Overview of Chronic Obstructive Pulmonary Disease: What Can Real-Life Data Tell Us about Disease Management?

Chronic obstructive pulmonary disease (COPD) is a common condition, associated with increasing age and smoking exposure. COPD is a leading cause of morbidity, mortality and health care expenditure worldwide; yet, only 10-15% of all cases are identified medically. Alpha-1-antitrypsin deficiency (AATD) is responsible for about 1% of COPD cases but is also largely under-recognised, leading to diagnostic delay and missed treatment opportunities in patients who remain undetected. New evidence has recently highlighted the extent of overlap between COPD and bronchiectasis and the implications of comorbidity on clinical course and mortality. COPD with comorbid bronchiectasis deserves to be given research priority. This article overviews the epidemiology of COPD and examines the implications of overlap between COPD and AATD and between COPD and bronchiectasis.

Cardiovascular risk in patients with alpha-1-antitrypsin deficiency

Background

Alpha-1-antitrypsin deficiency (AATD) is a rare inherited condition caused by mutations of the SERPINA1 gene that is associated with the development of a COPD like lung disease. The comorbidities in patients with AATD-related lung diseases are not well defined. The aim of this study was to analyze the clinical phenotype of AATD patients within the German COPD cohort study COSYCONET (“COPD and SYstemic consequences-COmorbidities NETwork”) cohort focusing on the distribution of comorbidities.

Method and results

The data from 2645 COSYCONET patients, including 139 AATD patients (110 with and 29 without augmentation therapy), were analyzed by descriptive statistics and regression analyses. We found significantly lower prevalence of cardiovascular comorbidities in AATD patients as compared to non-AATD COPD patients. After correction for age, pack years, body mass index, and sex, the differences were still significant for coronary artery disease (p = 0.002) and the prevalence of peripheral artery disease as determined by an ankle-brachial-index <= 0.9 (p = 0.035). Also the distribution of other comorbidities such as bronchiectasis differed between AATD and non-deficient COPD.

Conclusion

AATD is associated with a lower prevalence of cardiovascular disease, the underlying mechanisms need further investigation.

Electronic supplementary material

The online version of this article (10.1186/s12931-017-0655-1) contains supplementary material, which is available to authorized users.

Down-regulation of hepatocyte nuclear factor-4α and defective zonation in livers expressing mutant Z α1-antitrypsin

α₁ -Antitrypsin (AAT) deficiency is one of the most common genetic disorders and the liver disease due to the Z mutant of AAT (ATZ) is a prototype of conformational disorder due to protein misfolding with consequent aberrant intermolecular protein aggregation. In the present study, we found that livers of PiZ transgenic mice expressing human ATZ have altered expression of a network of hepatocyte transcriptional factors, including hepatocyte nuclear factor-4α, that is early down-regulated and induces a transcriptional repression of ATZ expression. Reduced hepatocyte nuclear factor-4α was associated with activation of β-catenin, which regulates liver zonation. Livers of PiZ mice and human patients with AAT deficiency were both found to have a severe perturbation of liver zonation. Functionally, PiZ mice showed a severe defect of ureagenesis, as shown by increased baseline ammonia, and reduced urea production and survival after an ammonia challenge. Down-regulation of hepatocyte nuclear factor-4α expression and defective zonation in livers have not been recognized so far as features of the liver disease caused by ATZ and are likely involved in metabolic disturbances and in the increased risk of hepatocellular carcinoma in patients with AAT deficiency.

CONCLUSION

The findings of this study are consistent with the concept that abnormal AAT protein conformation and intrahepatic accumulation have broad effects on metabolic liver functions. (Hepatology 2017;66:124-135).

Costs and health-related quality of life in Alpha-1-Antitrypsin Deficient COPD patients

BACKGROUND

Alpha-1-Antitrypsin Deficiency (AATD) is an economically unexplored genetic disease.

METHODS

Direct and indirect costs (based on self-reported information on healthcare utilization) and health-related quality of life (HRQL, as assessed by SGRQ, CAT, and EQ-5D-3 L) were compared between 131 AATD patients (106 with, 25 without augmentation therapy (AT)) and 2,049 COPD patients without AATD participating in the COSYCONET COPD cohort. The medication costs of AT were excluded from all analyses to reveal differences associated with morbidity profiles. The association of AATD (with/without AT) with costs or HRQL was examined using generalized linear regression modelling (GLM) adjusting for age, sex, GOLD grade, BMI, smoking status, education and comorbidities.

RESULTS

Adjusted mean direct annual costs were €6,099 in AATD patients without AT, €7,117 in AATD patients with AT (excluding costs for AT), and €7,460 in COPD patients without AATD. AATD with AT was significantly associated with higher outpatient (+273%) but lower inpatient (-35%) and medication costs (-10%, disregarding AT) compared with COPD patients without AATD. There were no significant differences between groups regarding indirect costs and HRQL.

CONCLUSION

Apart from AT costs, AATD patients tended to have lower, though not significant, overall costs and similar HRQL compared to COPD patients without AATD. AT was not associated with lower costs or higher HRQL.

TRIAL REGISTRATION

NCT01245933.