Asthma common in alpha-1 antitrypsin deficiency patients
Aug 02, 2006 - Asthma is common in patients with alpha-1 antitrypsin deficiency (AATD) and is usually associated with chronic obstructive pulmonary disease (COPD), suggesting that patients with the deficiency should undergo allergy evaluation, say US scientists.
AATD contains a wide range of AAT phenotypes that confer varying susceptibility to obstructive lung disease and emphysema. The most common variant for homozygous severe deficiency is protease inhibitor (Pi) Z, giving the PiZZ phenotype.
Seeking to identify the prevalence of asthma and atopy in AATD individuals, Edward Eden, from Columbia University in New York, and colleagues sent a survey to 2418 individuals in the Alpha-1 Foundation Research Registry.
The 757 responses revealed that 44.6% had been diagnosed with asthma, while wheezing was reported by 76%. Common triggers were respiratory infections, activity and exposure to dusts, fumes, and allergens.
Dividing the patients into those with the PiZZ phenotype, those with the less severe PiMZ phenotype, and other phenotypes showed that the prevalence of asthma ranged from 20–25%, with wheezing significantly less common in the PiMZ group than in the others.
Of those with asthma, 83% of PiZZ individuals also had a diagnosis of COPD, compared with just 48% of those in the PiMZ group, the team writes in the journal Respiratory Medicine. Asthma was three times more prevalent as the only reported diagnosis in the PiMZ group than in the PiZZ group.
“Asthma is difficult, if not impossible, to distinguish clinically from COPD in those with established airflow obstruction,” the researchers write.
“Given the overlap between asthma and COPD in this population and the potential impact of asthma on forced expiratory volume in 1 second loss, evaluation of the wheezy patient with AATD should include allergy testing and aggressive treatment to reduce bronchial hyperresponsiveness.”
Respir Med 2006; 100: 1384–1391
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