The Correlations of FeNO, Blood Eosinophils and Lung Function in Well-controlled Asthma

Study Overview
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Brief Summary
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In Asthma, the levels of exhaled FeNO is correlated to sputum eosinophils particularly in the patient with poor controlled asthma or severe asthma. Moreover, the blood eosinophils had been studied that are also correlated to sputum eosinophils in similar patients group. According to well controlled asthma, althoug hin clinical practice guidelines recommend that the stepping down therapy should be considered to those patients due to the risks or costs of daily treatment, there is previous study has been shown that the airway hyperresponsiveness and sputum eosinophilia are predictors of loss of control during dose reduction. And, these tests are not readily available in primary care. However, there is limit number of clinical study to study the correlation of biologic markers among the patients with well controlled level before the stepping down management.

Detailed Description
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This is a single prospective trial. Enrollment will continue until 50 patients with well controlled asthma have been entered into this trial and have completed blood tests and spirometry. In this trial, the following parameters are to be evaluated: Blood eosinophils (absolute and relative) FeNO Pulmonary lung function test: FEV1, FVC, PF, MMEF 25-75%, % reversibility

Official Title
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The Correlations of FeNO, Blood Eosinophils and Lung Function in Well-controlled Asthma Based on Asthma Controlled Questionnaires

Conditions
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Asthma

Intervention / Treatment
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* Diagnostic Test: Patients with well controlled asthma


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with diagnosis of asthma (according to the guidelines) Age >15 years Patients with treating with step 3 base on GINA by only low dose ICS/LABA without oral bronchodilator with being in well controlled asthma based on ACT (> = 23) and ACQ-7 (<0.75) for at least 12 weeks Ability to provide informed consent and do spirometry following ATS guideline Exclusion Criteria: Pulmonary infection or exacerbation within the last 12 weeks before enrolment Patients with preceding taken systemic steroid 12 week before enrolment Additional pulmonary diseases (pneumonia, lung cancer, tuberculosis, interstitial lung disease) A history of smoking >= 10 pack-year

Ages Eligible for Study
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Minimum Age: 15 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: Patients with well controlled asthma|Patients with well controlled asthma The following parameters are to be evaluated: Blood eosinophils FeNO Findings on lung function test|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assessment of eosinophilic inflammation by correlating blood eosinophil count, FeNO measurement and lung function test | Correlation of FeNO, blood eosinophils, lung function test in patients with well controlled asthma before stepping down medication | 3 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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FeNO, Blood eosinophil, Pulmonary function test, Well controlled asthma