Objective: Early intervention in chronic obstructive pulmonary disease (COPD) includes health education, smoking cessation, pulmonary rehabilitation and enhancing immunity (administration of influenza vaccine and polysaccharide nucleic acid fraction of bacillus Calmette-Guerin [BCG-PSN]). The effect of early intervention was investigated systematically in patients with COPD at different stages.

Methods: We enrolled 422 patients with COPD at different stages without symptoms and then randomly assigned them to intervention and control groups. The intervention group was provided with early intervention and usual care while the control group was only provided with usual care. One year of follow-up was performed to observe forced expiratory volume in one second (FEV1), FEV1/forced vital capacity (FVC), and the ratio of patients with acute exacerbation (number of patients with acute exacerbation/total of patients).

Results: The values of decline in FEV1 and FEV1/FVC were significantly lower in the intervention groups of stage I and II than control groups (all p < 0.05), but not significantly lower in the intervention groups of stage III and IV than control groups (all p > 0.05). The ratios of patients with acute exacerbation were lower in the intervention groups of all the stages than the control groups (p < 0.05).

Conclusion: Early intervention could slow the decline of FEV1 and FEV1/FVC in patients with COPD in stages I and II, but not in stages III and IV. Early intervention could also prevent patients with COPD from getting acute exacerbation and improve their quality of life in all the stages of the disease.