S86 BRONCHODILATOR REVERSIBILITY AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE: RELATIONSHIP TO LUNG FUNCTION, COMPUTED TOMOGRAPHY SCANS AND PROGRESSION

RI Carter, AM Wood, RA Stockley. University Hospital Birmingham NHS Foundation Trust, Birmingham, UK

Introduction and Objectives: Chronic obstructive pulmonary disease (COPD) is characterised by airflow limitation with a post-bronchodilator FEV₁ : FVC less than 0.7.1 Reversibility (post-bronchodilator increase in FEV₁ of 12% and 200 ml)1 is still used to exclude a diagnosis of COPD;2 however, recent baseline data from the UPLIFT trial have shown that the majority of patients with COPD fulfil these criteria.3 An increase of 400 ml is considered clinically significant,1 is highly suggestive of asthma and should be treated as such.4 The current study explores the relationship between spirometric bronchodilator response and other lung function tests and computed tomography (CT) scans in patients with a diagnosis of COPD including a 4-year follow-up.

Methods: The study population consists of well-characterised patients with post-bronchodilator FEV₁ : FVC less than 0.7 and clinical features of COPD. Full lung function tests and CT analysis (presence of visible emphysema and densitometry) were performed at baseline and at 4 years. The results of these were compared for three groups based on FEV₁ increase post-bronchodilator: A <200 ml or <12%; B >12% and >200 ml but <400 ml; C >400 ml.

Results: There was no significant difference in smoking status, gender or age between the three groups. However, group C had a significantly greater baseline FEV₁ (% predicted) and absolute decline in FEV₁ but a lesser decline in lower zone voxel index and KCO (% predicted). In addition, group C had a greater decline in FEV₁ (% predicted), although this just fell short of the criteria for significance relative to group B (p = 0.058). The results are summarised in the table.

Conclusions: The majority of patients in this study exhibited a …