Obesity and Asthma:a Specific Phenotype (ORPA)
Clinicians frequently observed that obese women referred for severe asthma do not respond to treatment. These patients, despite the presence of wheezing, often have normal expiratory flows and normal or "borderline" airway responsiveness.
It is therefore possible that this mode of presentation reflect a pseudo-asthmatic state for which clinical definition and characteristics and optimal management remain to be determined.
The aim of this study was to study the pulmonary physiological and airway inflammatory characteristics and response to treatment of obese women considered to have clinically severe asthma in order to demonstrate that some of these patients have a phenotype that is not that of asthma.
|Study Design:||Observational Model: Case Control
Time Perspective: Cross-Sectional
|Official Title:||Obesity-related Pseudo-asthma (ORPA): Description of a Novel Clinical Entity|
|Study Start Date:||September 2005|
|Study Completion Date:||September 2010|
Obese subjects with asthma (on inhaled corticosteroids)
Non obese asthmatics
Non obese subjects with asthma (on inhaled corticosteroids)
Twenty-five obese women (BMI over 30) and 25 non-obese women (18>BMI<25) considered to have severe asthma by their physician and requiring corticosteroids to control their asthma will have the following investigation:
- Respiratory questionnaires focussing on the nature and time-course of symptoms, asthma control criteria, medication use.
- Physical examination, including measures of BMI, waist, hips and ratio waist/hips
- Blood test for Complete Blood Count, blood glucose, total IgE levels and markers of systemic inflammation (C-Reactive Protein, fibrinogen…)
- Spirometry and bronchodilator response.
- Induced sputum analysis and Exhaled Breath Condensate pH to assess airway inflammation.
- Skin prick tests with a battery of common airborne allergens
- Measurement of lung volumes and airway resistance + MIP and MEP.
- Methacholine challenge (up to 16 mg/ml) with Borg scores for breathlessness and chest tightness.