Objective: To evaluate the epidemiological characteristics of non-symptomatic chronic obstructive pulmonary disease (COPD) patients in a rural area in Beijing.
Methods: The data of 1,624 people aged more than 40 in 5 villages in Yanqing county in Beijing were collected. Information of medical history and symptom were obtained, and physical examination and lung function test were performed.
Results: The prevalence of COPD was 9.1% (148/1 624) in this area. In these 148 patients, 62 (42%) were non-symptomatic and 86 (58%) were symptomatic, the prevalence of non-symptomatic COPD being 3.8% (62/1 624). There was no statistical difference in the sex, age, occupation, marriage status, education level and smoking index between the symptomatic and the non-symptomatic groups (all P > 0.05). The forced expired volume in one second (FEV(1)) and FEV(1)% predicted were lower in the symptomatic group [(1.3 +/- 0.7) L, (61 +/- 23)%] than those in the non-symptomatic group [(1.5 +/- 0.6) L, (70 +/- 22)%; all P < 0.05].
Conclusions: The prevalence of COPD was high in this area with a high percentage of non-symptomatic patients. The COPD prevalence might be underestimated due to the symptom free patients.