The aims of the current study are to compare available tests for small airway function in asthmatic patients and to assess differences in small airway function between obese and non-obese asthmatic patients.
ID
Source
Brief title
Condition
- Lower respiratory tract disorders (excl obstruction and infection)
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
Compare available tests for small airway function in asthmatic patients. The
primary endpoint is Impulse Oscillometry.
Secondary outcome
Other small airway measurements:
- spirometry
- multiple breath nitrogen washout
- body plethysmography
- RGA Single breath CO-diffusion (TLCO, KCO, VA)
- fraction exhaled nitric oxide
Other airway tests
- methacholine provocationtest
- eosinophils in sputum en blood
Questionnaires:
- Asthma control
- Bronchial hyperreactivity
- Asthma specific quality of life
- Small Airway Disease
- Medication adherence
Background summary
Overweight and obesity has reached epidemic proportions. In 2014, 600 million
adults were obese. Obesity is a risk factor for multiple chronic diseases,
including asthma. Prospective studies identified an increased odds of 1.51 to
develop asthma at 1 year follow-up in overweight or obese individuals compared
with normal weight individuals. This translates into 250.000 new adult cases of
asthma each year in the United States attributable to overweight and obesity.
Additionally, obese asthmatic patients have lower quality of life and worse
symptom control than non-obese asthmatic patients. Traditionally asthma is
considered an obstructive disease of the large airways. However, current
evidence shows that asthma affects the whole respiratory tract, including the
airways with a diameter less than 2 millimeter. Because the contribution of
these small airways to lung resistance is minimal, they were historically
called the *quiet zone*. However, these small airways account for 98.8% of the
total lung volume and in asthma patients small airway dysfunction is clearly
associated with worse symptom control and higher number of exacerbations.
Recent studies in obese asthmatic patients showed that weight loss improves
asthma symptoms. Interestingly, a simultaneous improvement in small airway
function was observed. So, asthma in obese patients is associated with worse
small airway function. This could be of clinical importance for obese asthmatic
patients, as extra-fine inhalation medication is available to target this
compartment of the lung. Yet, no gold standard exists to assess small airway
function and previous studies only used a minority of the available tests.
Additionally, only a few studies compared differences in small airway function
in obese and non-obese individuals. Until now, no study directly compared
several tests to assess small airway function in asthmatic patients with or
without obesity.
Study objective
The aims of the current study are to compare available tests for small airway
function in asthmatic patients and to assess differences in small airway
function between obese and non-obese asthmatic patients.
Study design
Cross-sectional
Study burden and risks
Participants will visit the study center three times, each time 2 hours. During
these visits, lung functions tests are performed. Questionnaires of 17 pages
are administered to participants. During the lung function tests, participants
can experience light dyspnoea. They will be administered a bronchodilator,
which quickly relieves the dyspnoea. After the tests they could experience some
soreness of the throat or cough. The lung function tests are a burden, but
without risks.
Albinusdreef 2
Leiden 2333ZA
NL
Albinusdreef 2
Leiden 2333ZA
NL
Listed location countries
Age
Inclusion criteria
* Age * 18 who have signed informed consent form prior to the start of the study
* Clinical diagnosis for * 6 months of asthma
* Stable asthma: on a stable dose of asthma inhalation medication for at least 8 weeks prior to baseline visit
* Obese (BMI >30) or non-obese (BMI <30)
Exclusion criteria
* Change of asthma inhalation medication in the past 8 weeks before visit 1
* Asthma exacerbation (defined as use of oral or intravenous corticosteroids and/or antibiotics) in the past 8 weeks before visit 1
* Smokers: current * 10 cigarettes per day or *10 pack years
* Diagnosis of COPD
* Pregnancy, as reported by the participant
* Clinical or functional uncontrolled respiratory- or other disease that might, in the judgement of the investigator, comprise the results or interpretation of the study
* Current- or less than 1 month from baseline participation in interventional clinical trial with inhalation drugs
* Inability to comply with study procedures
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
In other registers
| Register | ID |
|---|---|
| CCMO | NL54867.058.15 |
| OMON | NL-OMON23609 |