COPD incidence in subjects with risk factors, chronic respiratory symptoms and normal spirometry: The PLATINO study>

Background: the GOLD-2001 staging system establishes a stage at risk for developing COPD (GOLD 0), however this was subsequently discrded because there is no evidence that these subjects were more likely to develop COPD. Despite this, persits the controversy about the factor that help identify susceptible subjects. The aim of this study is to determine the factors associated with COPD incidence in the PLATINO follow-up study Methods: COPD incidence rate was determined per 1000 subjects with GOLD criteria, adjusted by confounders. Dyspnea and chronic bronchial hypersecretion were self-reported and smoking was measured in pack-years. Results: 1797 subjects completed the follow-up and 154 incident cses were identified. The incident rate in smokers with ≥ 10 and ≥20 packs/year were 16 cases/year (IRR:1.54; p 0.05) and 17.1 cases/year(IRR:1.13;p>0.05). There was no increment inthe incident rate by associating the symptoms with smoking history. In the Poisson adjusted analysis, the associated factors identified were: age≥ 60 years and low baseline FEV1 . Conclusions: Smoking history >20 packs/year, low baseline VEF1 and age ≥60 years regardless the presence of respiratory symptoms were the main factors associated with COPD incidence. Future studies are needed to determine other factors or biomarkers that help identify subjects at risk to developing COPD