Prevalence and impact of bronchiectasis in alpha1-antitrypsin deficiency.
BACKGROUND
alpha(1)-Antitrypsin (AAT) deficiency is associated with increased risk of chronic obstructive pulmonary disease (COPD), in particular emphysema, but airway disease is less well described.


OBJECTIVE
To assess the prevalence of airways disease in subjects with AAT deficiency and to identify the relationship between radiological airway abnormalities and clinical phenotype.


METHODS
We characterized the computed tomographic phenotype of 74 subjects (PiZ), using visual scoring of airway disease and densitometric assessment of emphysema. Computed tomographic measurements were related to physiology, health status (St. George's Respiratory Questionnaire), and emphysema severity, and the relative impact of airway disease and emphysema severity on health status and airflow obstruction was compared by stepwise regression.


RESULTS
Bronchiectatic changes were seen in 70 subjects, and a subgroup with a bronchiectasis-predominant phenotype was identified. Clinically significant bronchiectasis (radiologic bronchiectasis in 4 or more bronchopulmonary segments together with symptoms of regular sputum production) occurred in 20 subjects (27%). AAT-deficient index cases had higher airway disease scores (P < 0.05), more severe emphysema (P < 0.001), and greater impairment of physiology (P < 0.001) and health status (P < 0.05) than nonindex cases. Airway disease scores correlated with health status, and bronchial wall thickening correlated with FEV(1). Regression analysis indicated that emphysema severity had the strongest associations for health status (r = 0.505, P < 0.001) and FEV(1) (r = 0.699, P < 0.001), but the addition of airway disease score improved the regression models (r = 0.596, P = 0.002 and r = 0.783, P < 0.001, respectively).


CONCLUSIONS
Emphysema is the predominant component of COPD in AAT deficiency, but the prevalence and impact of airway disease are greater than currently recognized. Consequently, future therapeutic strategies in AAT deficiency should also target this component of COPD.
Parr
David G
DG
Department of Respiratory Medicine, University Hospitals of Coventry and Warwickshire, Coventry CV2 2DX, UK. david.parr@uhcw.nhs.uk
Guest
Peter G
PG
Reynolds
John H
JH
Dowson
Lee J
LJ
Stockley
Robert A
RA
D000328:Adult; D001987:Bronchiectasis / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D015995:Prevalence; D011656:Pulmonary Emphysema / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed; D006113:United Kingdom / Q000453:epidemiology; D019896:alpha 1-Antitrypsin Deficiency / Q000150:complications / Q000453:epidemiology*