Are we overlooking persistent small airways dysfunction in community-managed asthma?

• Published in: Annals of allergy, asthma, & immunology Vol. 109; no. 3; pp. 185 - 189.e2
• Main Authors: Anderson, William J., MBChB, Zajda, Emma, BSc, Lipworth, Brian J., MD
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.09.2012; Elsevier
• Subjects: Administration, Inhalation; Adrenal Cortex Hormones - administration & dosage; Adrenal Cortex Hormones - therapeutic use; Adult; Airway Resistance - drug effects; Albuterol - administration & dosage; Albuterol - analogs & derivatives; Albuterol - therapeutic use; Allergy and Immunology; Androstadienes - administration & dosage; Androstadienes - therapeutic use; Anti-Asthmatic Agents - administration & dosage; Anti-Asthmatic Agents - therapeutic use; Asthma - drug therapy; Asthma - physiopathology; Beclomethasone - administration & dosage; Beclomethasone - therapeutic use; Biological and medical sciences; Bronchodilator Agents - administration & dosage; Bronchodilator Agents - therapeutic use; Chronic obstructive pulmonary disease, asthma; Dermatology; Drug Combinations; Female; Fluticasone-Salmeterol Drug Combination; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Male; Medical sciences; Middle Aged; Oscillometry - methods; Pneumology; Respiratory Function Tests; Respiratory System - physiopathology; Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis; Spirometry - methods; Respiratory tract; Lung disease; Immunopathology; Immunology; Respiratory disease; Dermatology; Dysfunction; Bronchus disease; Obstructive pulmonary disease; Respiratory system; Community; Asthma
• ISSN: 1081-1206; 1534-4436
• DOI: 10.1016/j.anai.2012.06.022

Abstract Background Whether small airways dysfunction persists in patients with asthma receiving standard community treatment is unknown. Impulse oscillometry (IOS) is a sensitive measure of small airways function. Objective To assess the degree of small airways dysfunction in a cross-section of patients with community-managed asthma. Methods We analyzed primary care referral data from patients with persistent asthma ( n = 378) receiving standard community therapy, screened using spirometry and IOS. We compared patients by British Thoracic Society asthma treatment step (2–4). Results Step 2 patients were not different from step 3 patients receiving long-acting beta-agonist (LABA). Step 4 patients differed from step 2 by: higher inhaled corticosteroid (ICS) dose ( P < .0001); lower forced expiratory volume in 1 second (FEV1 %; P = .02) and forced mid-expiratory flow (FEF25–75% ; P = .001); higher frequency of resonance (Fres ; P = .02) and peripheral airway resistance (R5-R20; P = .006); whereas for steps 3 vs 4 there were differences in Fres ( P < .05) and R5-R20 ( P = .006). There were high proportions of abnormality for R5-R20 (>0.03 kPa/L/s) at steps 2, 3, and 4, respectively: 64.6%, 63.5%, and 69.9%. Step 2 patients receiving extra-fine particle ICS demonstrated lower total airway resistance at 5Hz (R5) vs patients receiving standard ICS (124.1% vs 138.3%, P < .05), with no difference in FEV1 . At step 4, R5 remained elevated at 141.3% despite concomitant LABA, with only 2.4% using extra-fine ICS. Conclusion Persistent small airways dysfunction occurs despite treatment at steps 2 through 4 of current asthma guidelines. Extra-fine ICS may reduce airway resistance at step 2. Prospective studies with extra-fine ICS ± LABA at steps 2 through 4 are required to discern whether improving small airways function might result in long-term improved control.