Efficacy of different questionnaires in screening COPD in the communities of Songjiang District， Shanghai

Objective To evaluate the efficacy of three screening questionnaires for COPD in the community residents of Songjiang District， Shanghai， and to provide a basis for selecting COPD screening questionnaire and process that are more suitable.

Methods Community residents aged 40 years or over were randomly selected from the Shanghai Suburban Adult Cohort and Biobank for the study with screening questionnaires and spirometry. Questionnaires included the COPD screening questionnaire （COPD-SQ）， the COPD population screener （COPD-PS） and the revised COPD diagnostic questionnaire （revised-CDQ）. Evaluation of the efficacy of these questionnaires was based on the area under the receiver operating characteristic curve （AUC） of the subjects. DeLong test was used to compare the accuracy of different questionnaires； Z test was used to compare the accuracy of different cut-off values for the same questionnaire.

Results Among 3 184 community residents， a total of 259 （8.1%） COPD patients were screened by spirometry. AUC values of these 3 screening questionnaires were >0.7 indicating that they were reliable COPD screening tools. The sensitivity and specificity of the questionnaires at the recommended cut-off values were COPD-SQ （63.7% and 72.2%）， COPD-PS （12.0% and 96.1%）， and revised CDQ （78.8% and 52.7%）， with the COPD-SQ having the highest screening accuracy （AUC=0.754）. The optimal and recommended cut-off values for the three questionnaires differed in this population， but the difference in accuracy was statistically significant only for COPD-PS. The optimal cut-off values for the three questionnaires differed between male and female， and the sensitivity and accuracy of COPD-SQ and COPD-PS improved when lower cut-off values were used for women. The AUC was greater when two questionnaires were utilized simultaneously for screening， but the differences were not statistically significant.

Conclusion The COPD-SQ is recommended for primary COPD screening； a lower cut-off value for women should be considered. The COPD screening questionnaire needs to be further improved for the early diagnosis and treatment of COPD patients.