Bronchodilator reversibility in Australian adults with chronic obstructive pulmonary disease

Background and aims: Bronchodilator reversibility (BDR) and inhaled corticosteroid (ICS) use were assessed for volunteers who responded to an advertisement requesting current or ex-smokers who were experiencing breathlessness to attend for lung function testing. Methods: One hundred and fifty-four volunteers responded. Forced expiratory volume (FEV1) was measured before and after 400 μg of salbutamol. Significant BDR was assessed according to guidelines of: (i) the American Thoracic Society (≥12% plus 200 mL of baseline FEV1 or forced vital capacity), (ii) the British Thoracic Society (BTS) (≥15% plus 200 mL of baseline FEV1), (iii) the European Thoracic Society (≥10% predicted FEV1), and (iv) the most commonly used criteria in Australia and New Zealand (≥15% of baseline FEV1). Results: One hundred and twenty-three subjects (33 female; 40 current smokers; median pack years 48 (range 5-144)) were suitable for analysis (i.e. had no history of asthma, demonstrable airflow limitation and a forced expiratory ratio (FER) of <70%). Twenty (16%) patients had an FEV 1 within the normal range but FER of <70%, 24 (20%) patients had mild disease (FEV1 60-80% predicted), 31 (24%) patients had moderate disease (FEV1 40-59% predicted), and 48 (39%) patients had severe disease (FEV1 <40% predicted), according to BTS criteria. Significant BDR was evident in: (i) 58 (47%) subjects by American criteria, (ii) 26 (21%) subjects by British criteria, (iii) 19 (15%) subjects by European criteria and (iv) 36 (29%) subjects by Australasian criteria. ICS use was reported by 71 (58%) subjects overall and was weakly, but significantly, related to poorer FEV1 (r = -0.2; P < 0.01), and greater BDR (r = 0.3; P < 0.005). Conclusion: Chronic obstructive pulmonary disease in Australian volunteers with no history of asthma encompasses many individuals with significant BDR. Interestingly, most volunteers reported ICS use and this was related to poorer spirometry and greater BDR. However, until the underlying immunopathology has been determined they cannot be assumed to have 'asthma' or even an 'asthmatic element'.