Combination therapy in COPD: different response of COPD stages and predictivity of functional parameters.

BACKGROUND Inhaled corticosteroids reduce exacerbations in patients with chronic obstructive pulmonary disease (COPD) but they do not affect disease progression. FEV1, as single parameter, showed limits in describing the heterogeneity of COPD population. Combination therapy, with long-acting Beta2-agonist and corticosteroid, showed a more beneficial effect on lung function, exacerbations, and health status than single inhaled drug. The aim of this study was to assess, in stable COPD, which stage (mild, moderate, severe) shows the best response after 12 weeks inhaled treatment, and which starting functional parameters show a correlation with the response. METHODS 170 stable COPD patients (38 mild, 66 moderate, 66 severe) were enrolled. Patients received salmeterol/fluticasone 50/500 microg Metered Dose Inhaler (MDI) bid for 12 weeks. Pulmonary function tests and clinical data were performed. Results were subdivided, on functional and clinical data, in "responders (R)" and "no-responders (NR)". RESULTS A FEV1 improvement (+ 12% and 200 ml) was achieved in 21 mild, 28 moderate and 17 severe COPD patients, respectively 55.3%, 45.9%, and 30.9% of each group. Statistical analysis of starting functional parameters showed a correlation with the therapeutic response for FEV1/FVC, MEF50 and DLCO/VA% (p < 0.05). CONCLUSIONS Salmeterol/fluticasone improves FEV1% in mild and moderate more than in severe COPD patients. The study confirmed the difference in response between early and advanced stage. Starting FEV1/FVC and MEF50 were significant predictors in mild and moderate stages, and starting DLCO/VA% resulted a significant predictor in moderate and severe stages.