Sex Differences in the International Primary Care Airways Group Questionnaire for Screening of Chronic Obstructive Pulmonary Disease: A Retrospective, Cross-Sectional Study

Background and Objective: The International Primary Airways Group (IPAG) questionnaire is a useful tool for screening for chronic obstructive pulmonary disease. The cut-off score of the IPAG questionnaire is investigated in Japan. However, its validity has not been examined according to sex, which was the aim of this study. Methods: We included 4364 participants aged 40 years or older, all current and ex-smokers and never-smokers, who completed the IPAG questionnaire and underwent spirometry. The IPAG questionnaire consists of eight items and the cut-off score is set to 17. We calculated the odds ratios of airflow limitation for each of the eight questions, by sex. We performed receiver operating characteristic analysis, calculating the area under the curve, sensitivity, and specificity for each sex. Results: For both men (n=2784) and women (n=1580), only three questions were independent risk factors of airflow limitation. The odds ratios for age (>70 years), wheezing, and smoking history (>50 pack-years) were 10.61, 3.50, and 2.40, respectively, for men (all p<0.001), and 4.30 (p<0.001), 2.32 (p=0.026), and 5.69 (p=0.014), respectively, for women. For men and women, the areas under the curve were 0.741 and 0.670, respectively. The sensitivity and specificity values, respectively, were as follows: 83.6% and 47.1% for men with a cut-off score of 17; 80.0% and 53.7% for men with a cut-off score of 18; 56.7%, and 65.9% for women with a cut-off score of 17; and 76.7% and 43.9% for women with a cut-off score of 15. Conclusion: Regardless of sex, only three IPAG questions were deemed useful as screening for airflow limitation. The cut-off scores for men and women may be appropriately set at 18 and 15, respectively, in the Japanese population.