[Does tobacco abstinence in patients with chronic bronchial obstruction make sense?]

In 60 patients with advanced COPD, lung function was studied retrospectively at the beginning and end of a 12 to 175 months' test period. 25 patients continued to smoke 5 or more cigarettes daily (smokers). The other 35 patients were ex-smokers or smoked only 1 to 4 cigarettes daily during the trial (non-smokers). In the heavy smoker group FEV1 diminished much more rapidly than in the non-smoking group (p less than 0.01). We observed a significant dose-response ratio between the number of cigarettes smoked and the decrease in FEV1 (r = 0.27, p less than 0.025). No causes other than smoking were found for the fall in FEV1: age, weight, place of residence, profession, sputum evaluation and inhalation therapy were statistically equal in the non-smoking and the smoking group. However, one unexpected result was that more non-smokers had had long term treatment with steroids than smokers. This may mean that non-smokers have better compliance or that there is a subgroup more sensitive to COPD who thus take more steroids and are more inclined to stop smoking than a less sensitive population. The question remains open.