Initial Validation And Evaluation On A Chinese-version Of Chronic Obstructive Pulmonary Disease Screening Questionnaire In Smokers

Background:Chronic obstructive pulmonary disease (COPD) has high morbidity and mortality. Early flow limitation should be identified among people who are at risk of COPD, especially among the smokers. Screening questionnaires are often simple, inexpensive and efficient. It can make up for the limitation of spiromatry if some COPD screening questionnaires can be used widely, but now this kind of questionnaires is few. International Primary Care Airway Group has recommended the symptom-based questionnaire for smokers aged 40 years and over. But few studies have been reported whether the questionnaire is applicable to smokers in China.Objective:To get a Chinese version of symptom-based questionnaire and to determine whether the screening questionnaire is applicable to initial screening COPD among our smokers.Methods:A methodology study design was used. It was performed as follows:In the first part, the Chinese version questionnaire was formed and face validity, content validity and acceptability of the questionnaire were tested by the specialists and a pilot study in smokers; In the second part, a convenient sample of 349 smokers (141 in COPD group and 208 in non-COPD group) were enrolled who received pulmonary function test (PFT) at PFT departments in 2 hospitals in Beijing. Subjects with a postbronchodilator forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio of<70% were defined as COPD patients. They all completed the screening questionnaire after PFT. All the data were collected and the measurement indices were validated.Results:(1) The questionnaire was characteristic of good face validity, content validity (CVI=0.98); recovery and qualified rate of the questionnaire were high, and the average time spent on finishing the questionnaire was 3.50±0.88 min, which showed a good acceptability. (2)A good discrimination validity was shown, the score of COPD group was significantly higher than that of non-COPD group (Z=-13.221, P<0.01). A significantly positive correlation was found between the scores of the questionnaire and their PFT results (r=0.541, P<0.01). With a cut-off value of 17 points, the sensitivity (Se), specificity(Sp), positive likelihood ratio (+LR), negative likelihood ratio (-LR), Youdenn's index, positive predictive value (+PV) and negative predictive value (-PV) were 87.9%,66.8%,2.65,0.18,0.547,64.2%, and 89.1%, respectively. By ROC analyzing, the area under the ROC curve (AUC-ROC) was 0.916; and 18.5 (19) points was found to be the best cut-off value. (3)Modifying the item BMI, the measurement indices of the questionnaire were better than before. Still with a cut-off value of 17 points, the sensitivity, specificity,+LR,-LR, Youdenn's index,+PV and-PV were 89.3%, 71.6%,3.14,0.15,0.609,68.1%and 90.9%, respectively. AUC-ROC of the modified questionnaire was 0.921, and the best cut-off value was 17.5(18) points.Conclusion:The Chinese-version of COPD Screening questionnaire is a brief, accurate tool that can identify smokers likely to have COPD. But adjustments should be made if the questionnaire is used in our country, a cut-off value of 19 points would be suggested when the items remain unchanged. But if the item of BMI is modified according to the Chinese BMI classification standard, a cut-off value of 18 points will be recommended.