Intense Airway Eosinophilia in Asthma

Characteristics of the Eosinophilic Asthma Phenotype: an Observational Study in Patients From a Tertiary Care Center With Various Asthma Severities: The Quebec Heart and Lung Institute-Laval University Retrospective Asthma Database Analysis

In asthma, the type and importance of the inflammatory response in the airways has allows identification of different phenotypes. Of these, one of the most common is eosinophilic asthma, based on induced sputum differential cell count. Patients with severe asthma and an eosinophilic asthma phenotype have different pathophysiological characteristics than those seen in patients with with mild asthma. However, few studies have compared patients with eosinophilic phenotype according to the severity of asthma. In addition, the stability of the phenotype based on the sputum results has been criticized.

This study aims to describe the characteristics of patients with eosinophilic asthma phenotype according to the severity of asthma and determine the stability of the phenotype.

Study Overview

• Status: Completed
• Conditions: Asthma; Eosinophilic Asthma

Detailed Description

Characteristics of asthmatic subjects with sputum eosinophilia will be compared according to asthma severity.

• Study Type: Observational
• Enrollment (Actual): 918

Contacts and Locations

Study Locations

• Canada
  • Quebec
    • Québec, Quebec, Canada, G1V 4G5
      • Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Quebec

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Asthmatic subjects from the Quebec city region.

Description

Inclusion Criteria:

• Aged 18 years and over

• With a proven diagnosis of asthma as defined by one of the above criteria of current guidelines (36):

  1. Forced expiratory volume in one second (FEV1) increase by at least 12% (and ≥200 ml) after administration of a bronchodilator
  2. Current asthma symptoms and a methacholine provocative concentration inducing a 20% fall in FEV1 (PC20) <16 mg/ml

  3. A respirologist's current diagnosis of asthma found in the patient's medical report 3. Non-smokers or smokers/ex-smokers defined as someone with a smoking history <10 pack-years 4. With sputum differential cell count result 5. Considered to receive optimal treatment for their disease (as per current guidelines except for patients included in exploratory objective 1.

     6. Stable asthma and asthma medication for at least 4 weeks before data analysis 7. Written informed consent obtained for inclusion in the database

     Exclusion Criteria:

     1. Any respiratory disease apart from asthma
     2. Current or ex-smokers should not have a smoking history ≥10 pack-year before data analysis. Patients who administer nicotine in other forms (patches, chew tobacco, e-cigarette, etc.) will be excluded
     3. Unstable asthma medication <4 weeks before data analysis
     4. Asthma exacerbation (see definition below) <4 weeks before data analysis
     5. Respiratory tract infection <4 weeks before data analysis

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Eosinophilic; Asthmatic patients showing 3% or more sputum eosinophils
Non-eosinophilic; Asthmatic patients showing less than 3% sputum eosinophils

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Asthma severity according to medication use	Prevalence of patients with 3% or more sputum eosinophils in mild, moderate and severe asthma	Baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
ACSS symptom sub-score	Comparison of asthma control between patients with 3% or more sputum eosinophils and patients with less than 3% sputum eosinophils	Baseline
FEV1 percent predicted	Comparison of forced expiratory volume in one second between patients with 3% or more sputum eosinophils and patients with less than 3% sputum eosinophils	Baseline

Collaborators and Investigators

• Sponsor: Laval University
• Collaborators: AstraZeneca
• Investigators: Principal Investigator: Louis-Philippe Boulet, MD, IUCPQ-UL

Study record dates

Study Major Dates

• Study Start (Actual): June 6, 2017
• Primary Completion (Actual): April 18, 2018
• Study Completion (Actual): August 3, 2018

Study Registration Dates

• First Submitted: October 2, 2018
• First Submitted That Met QC Criteria: October 3, 2018
• First Posted (Actual): October 5, 2018

Study Record Updates

• Last Update Posted (Actual): October 5, 2018
• Last Update Submitted That Met QC Criteria: October 3, 2018
• Last Verified: October 1, 2018

More Information

Terms related to this study

• Keywords: phenotype; eosinophil; cluster; asthma severity
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Immune System Diseases; Lung Diseases; Hypersensitivity, Immediate; Hematologic Diseases; Bronchial Diseases; Lung Diseases, Obstructive; Respiratory Hypersensitivity; Hypersensitivity; Leukocyte Disorders; Eosinophilia; Hypereosinophilic Syndrome; Asthma; Pulmonary Eosinophilia
• Other Study ID Numbers: CÉR21488

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No