TY - JOUR T1 - Small airway dysfunction is associated with poorer asthma control JF - European Respiratory Journal JO - Eur Respir J SP - 1353 LP - 1355 DO - 10.1183/09031936.00082314 VL - 44 IS - 5 AU - Arvind Manoharan AU - William J. Anderson AU - Joseph Lipworth AU - Ibrahim Ibrahim AU - Brian J. Lipworth Y1 - 2014/11/01 UR - http://erj.ersjournals.com/content/44/5/1353.abstract N2 - To the Editor:The clinical relevance of the small airways in persistent asthma has been gaining greater recognition in recent years [1]. Studies have shown that a significant proportion of asthmatics on standard treatment fail to achieve satisfactory asthma control. For example, in one study of 3421 asthmatic subjects who underwent guideline-driven dose titration with standard inhaled corticosteroids (ICS)/long-acting β-agonist (LABA) combination therapy over 1 year, only 41% achieved total control of their asthma while 71% were well controlled [2]. Anderson et al. [3] found a high prevalence of adult patients with persistent small airway dysfunction determined by impulse oscillometry (IOS) (assessed as the difference between the resistance at 5 Hz (R5) and that at 20 Hz oscillation (R20)) and spirometry (assessed as the forced expiratory flow at 25–75% of forced vital capacity (FEF25–75%)) across British Thoracic Society (BTS) treatment steps for asthma, many of whom had a preserved forced expiratory volume in 1 s (FEV1). This, in turn, suggests an unmet clinical need in terms of patients who may have a small airway asthma phenotype.We therefore evaluated whether small airway dysfunction was associated with worse control in adult asthmatics with a preserved FEV1 (>80% predicted). Spirometry and IOS measurements from unselected asthmatics referred from primary care who attended screening for clinical trials were linked to prescription data. The prescription data were obtained from the Tayside Health Informatics Centre (Dundee, UK), which links all community-dispensed prescriptions using a person’s unique identifier, the Community Health Index. Spirometry and IOS measurements from asthmatics were … ER -