A Brief and Effective Questionnaire for COPD Screening in High-Altitude Areas

Purpose To develop a reliable screening questionnaire for chronic obstructive pulmonary disease (COPD) for primary health care institutions in high-altitude areas. Patients and methods This was a large cross-sectional study. The study included individuals who resided at an altitude of more than 2100 meters, were aged 35 years or older. The data were randomly divided into a development set and a validation set at a ratio of 7:3. Single-factor and multifactor logistic regression equations were employed to identify pertinent variables and construct a scoring system. The receiver operating characteristic (ROC) curve, area under the curve (AUC), positive predictive value (PPV) and negative predictive value (NPV) were used to evaluate the discriminative ability of the questionnaire. Results A total of 2909 individuals were included in this study, including 1304 males (44.83%), with a median age of 47.00 (41.00-55.00) years. A multivariate analysis of the development set revealed that five variables (age, history of pulmonary tuberculosis, smoking status, household air pollution exposure and CPOD Assessment Test (CAT) score) were significantly correlated with COPD. A scoring system was constructed on the basis of these findings. The AUC for the model in the development set was 0.714, whereas that for the validation set was 0.726. ROC analysis indicated that the optimal diagnostic cutoff value for the score was 22 points, with a sensitivity of 85.0% and a specificity of 48.4%. The results indicated that the sensitivity of the model was the highest (87.3%) at altitudes between 2100 and 3000 meters, whereas the specificity was the highest (80.9%) at altitudes >4000 meters. The conclusions were essentially consistent when the lower limit of normal (LLN) was used to verify the values in different altitude areas. Conclusion The COPD screening questionnaire effectively screens COPD in high-altitude primary healthcare settings.