Prevalence and impact of co-morbidity in COPD due to Alpha 1 Antitrypsin deficiency

Abstract

Background

Alpha 1 antitrypsin deficiency (AATD) is a rare genetic cause of chronic obstructive pulmonary disease (COPD). There are a number of conditions which are recognized to be common as co-morbidities in COPD unrelated to AATD, and a co-morbidity specific prognostic score exists (COTE index). In this manuscript we sought to describe the COPD related, and unrelated, co-morbidities seen in AATD and assess their impact on outcome. The relevant literature is also reviewed.

Methods

All PiZZ AATD patients who have COPD from the UK AATD registry were selected, and graded for severity of COPD using the GOLD criteria. Medical notes were reviewed to ascertain co-morbidity, and used to calculate the COTE score. Each co-morbid condition was tested for association with GOLD stage and subsequent death. Multivariate analyses, adjusting for smoking, age and GOLD stage, were used to ascertain independent relationships to death. COTE score was compared between GOLD groups and between survivors and those that died. Selected co-morbid diseases were also assessed using multivariate analyses for their relation to lung function decline.

Results

The most common co-morbid disease in AATD was bronchiectasis (31.1% of patients). Some common COPD related conditions were seen, such as osteoporosis (11.9%). Liver disease was observed in 5.5% of patients. In univariate analyses the presence of osteoporosis, depression or gastro-oesophageal reflux (GORD) associated with GOLD stage, being more common in group D patients (all p<0.05). No co-morbid disease was associated with death after adjustment for co-variates. COTE scores were generally low and did not differ between survivors and those that died.

Conclusion

Co-morbid disease is common in AATD, but differs from usual COPD, and has little impact on mortality and lung function decline. The COTE index is not valid for use in AATD.