In some countries inhaled corticosteroids are widely prescribed for patients with chronic obstructive pulmonary disease (COPD), despite the lack of good studies to support their use. In the last 12 months these three important large, parallel group, placebo controlled studies have reported at scientific meetings but, at the time of going to press with this article, they have not been published. This review will give an individual view of what has been presented, and provide a basis for the assessment of the trials when they are published.

All three studies used similar definitions of COPD and excluded patients with a clinical diagnosis of asthma or significant bronchodilator responsiveness. The Copenhagen study also excluded those with a prednisolone response, which was found in only 5% of their otherwise unselected population. The Copenhagen study started with a random population survey which identified all those with an FEV₁/VC ratio of <70%, irrespective of their FEV₁. They have the least diseased group with a mean FEV₁ of 85% predicted and include many subjects whose FEV₁ was within the normal range; indeed, only 39% had an FEV₁ of <80% predicted. The subjects in the ISOLDE study were mostly recruited from respiratory clinics and have the most

severe COPD with a mean FEV₁ of 50% predicted. The EUROSCOP group is intermediate in severity with a mean FEV₁ of 77% predicted.

The EUROSCOP subjects were all current smokers, having failed to quit in a three month period during the run in. The ISOLDE subjects had all been smokers, but only 48% were smoking at trial entry. The Copenhagen study did not have any entry criteria relating to smoking; 76% were current smokers.

The principal outcome measure for all three studies was longitudinal decline in FEV₁. It …