Long-term outcomes in mild/moderate chronic obstructive pulmonary disease in the European community respiratory health survey

Abstract

RATIONALE: Little is known about the long-term outcomes of individuals with mild/moderate chronic obstructive pulmonary disease (COPD) according to spirometric criteria. OBJECTIVES: To test whether nonsmokers and asymptomatic subjects with a spirometric diagnosis of COPD have a steeper decrease in lung function and higher hospitalization rates than subjects without airway obstruction. METHODS: A total of 5,205 subjects without asthma (20-44 years of age) from the general population, with FEV(1) >or= 50% predicted at baseline, were followed for 9 years in the frame of an international cohort study. Percent decrease in FEV(1) (DeltaFEV(1)%) and the annual hospitalization rate for respiratory causes during the follow-up were assessed for each subject. MEASUREMENTS AND MAIN RESULTS: At baseline, 324 (6.2%) subjects had the prebronchodilator FEV(1)/FVC ratio less than the lower limit of normal (LLN-COPD), and 105 (2.0%) subjects had the same ratio less than 0.70 (modified GOLD-COPD). At follow-up, smokers with LLN-COPD (n = 205) had a greater mean DeltaFEV(1)% (1.7%; 95% confidence interval [CI], 0.8-2.7) and a higher hospitalization rate (rate ratio [RR], 2.52; 95% CI, 1.65-3.86) than normal subjects. Similarly, symptomatic subjects with LLN-COPD (n = 104) had DeltaFEV(1)% (2.0%; 95% CI, 0.8-3.3) and the hospitalization rate (RR, 4.18; 95% CI, 2.43-7.21) higher than the reference group. By contrast, nonsmokers and asymptomatic subjects with LLN-COPD had outcomes that were similar or even better than normal subjects. Among subjects with LLN-COPD, the association of symptoms with DeltaFEV(1)% varied according to smoking habits (P = 0.007); it was particularly strong in symptomatic smokers and disappeared in symptomatic nonsmokers. Similar results were found with the modified GOLD classification. CONCLUSIONS: In relatively young populations, COPD is associated with poor long-term outcomes in smokers and in symptomatic subjects only.