Small airways function in alpha-1 antitrypsin deficiency
Research type
Research Study
Full title
Assessment of small airways function in alpha-1 antitrypsin deficiency. A cross sectional study.
IRAS ID
311921
Contact name
Omar S Usmani
Contact email
Sponsor organisation
Research Governance and Integrity Team (RGIT)
Clinicaltrials.gov Identifier
NA, NA
Duration of Study in the UK
0 years, 11 months, 31 days
Research summary
Summary of Research
Alpha-1 antitrypsin deficiency (AATD) is an underrecognized genetic disorder, predisposing to the development of chronic obstructive pulmonary disease (COPD). Although several genetic variants have been described, the PiZZ genotype is the most prevalent in severe AATD. AATD is associated with increased lung function decline and increased mortality, especially amongst active smokers. Disease of the small airways plays a significant role in COPD and may reveal the presence of early disease. However, the contribution of small airways dysfunction in lung disease in patients with AATD is largely unknown. Thus, the aim of the proposed project is to undertake a comprehensive assessment of small airways function in AATD patients. We will select adult patients with AATD and patients with COPD without AATD and measure small airway function in a single occasion to see if it correlates with symptoms, quality of life, overall lung function, lung imaging and exercise capacity.Summary of Results
Alpha-1 antitrypsin deficiency (AATD) is a genetic disorder that makes the lungs vulnerable to emphysema (destruction of the lung tissue) and development of chronic obstructive pulmonary disease (COPD). In COPD, small airways (the most peripheral air tubes of our lungs) are commonly affected and play a significant role in the severity of the disease. However, whether small airways are not functioning well in AATD is largely unknown. Moreover, it has been shown that techniques sensitive to small airway dysfunction, such as oscillometry, when performed together with spirometry, offer significant information that correlate with quality of life (QoL) and exercise capacity in patients with COPD. The value of oscillometry in AATD is however unknown. Thus, our study aimed to assess the correlation of oscillometry with QoL and exercise capacity in AATD. For this purpose, we recruited 19 patients with AATD (PiZZ genotype) and 10 non-AATD COPD patients. QoL was assessed by the St’ George Respiratory Questionnaire and exercise capacity with the one-minute sit-to-stand test (STS). We performed oscillometry and multiple breath nitrogen washout. The results of a recent lung function test (spirometry, gas diffusion and body plethysmography), performed as part of the usual clinical practice, were retrieved by the patient’s medical file. Similarly, the most recent chest CT scan, if available, was retrieved from the medical file. Our results showed that by combining results from oscillometry and gas diffusion test, we were able to identify a group of patients with AATD that presented with the worst QoL. Moreover, oscillometry showed the strongest correlation with reduced exercise capacity. Therefore, we conclude that adding oscillometry to the usual clinical practice and routine lung function testing may offer significant information for the quality of life and exercise capacity of patients with AATD.REC name
West of Scotland REC 3
REC reference
22/WS/0159
Date of REC Opinion
2 Nov 2022
REC opinion
Favourable Opinion