In patients with chronic obstructive pulmonary disease (COPD), the treatment with inhaled corticosteroids (ICS) is controversial. Preliminary results of our recent pilot study in 30 COPD patients showed for the first time, that ICS response mey be predicted by a bronchoprovocation challenge test with mannitol. However, this finding needs to be proven in a placebo-controlled trial. For this cohort study, 100 corticosteroid-naive, non reversible (FEV1) patients with COPD will be recruited. Spirometry before and after bronchodilation will be measured at study entry and at four weeks run-in (only tiotropium) and at three month of treatment with tiotropium and ICS or placebo. Quality of life (St. George Respiratory Quality of Life Questionnaire) and exacerbation rate of COPD will be assessed. Measurement of exhaled nitric oxide and mannitol challenge will be performed at study entry and at 1 and 4 month. Primary endpoint will be improvement in FEV1 in each group (positive and negative mannitol challenge) after 3 months follow up. Secondary endpoints will be the difference in dose-response-curve in the mannitol challenge, exacerbation rate and change in quality of life after three month follow-up.
