Background: A study shows that spirometry missed 10.4% of patients with clinical COPD who have significant emphysema on chest CT scan, which became our research basis.

Aim: Early detection of COPD in smokers or former smokers using questionnaires.

Methods: Patients over 40 years of age who visited the Outpatient Clinic of Mongolia-Japan Hospital of MNUMS with clinical symptoms of COPD and a smoking history of 10 years and more were included. The participants were evaluated with a spirometry test, as well as clinical symptoms and smoking status with commonly used questionnaires. The significance of the comparisons was determined using Student's t-test and median test.

Results: 35 patients were included in our study, of which 14 (40%) had normal spirometry tests while 21 (60%) had abnormal spirometry results. The median value of the smoking index in a group with normal (Group 1) and abnormal (Group 2) spirometry results were 343.5 and 518.0, respectively, which showed no statistically significant difference (p=0.84). The average CAT score was 12.14±6.63 in Group 1, whereas in Group 2 it was 15.14±7.19. While in Group 1 the average COPD-PS score was 5.71±2.13, Group 2 had an average of 6.33±1.85. Both CAT and COPD-PS scores had no difference of significance in the two groups (p=0.22, p=0.38, respectively). Most of the patients in Groups 1 and 2 (50% and 38%) graded themselves as mMRC Grade 1.

Conclusion: The results showing there is no statistically significant difference in the severity of clinical symptoms and the risk of COPD in groups suggest that the presence of symptoms in smokers with normal spirometry results may be indicating the early stages of COPD