SUBTYPE ANALYSIS OF ATHLETIC PATIENTS WHO ARE SMOKERS WITH NORMAL SPIROMETRY

Abstract

Objective: To determine the heterogeneity in smokes with normal spirometry from chest CT. Methods: By Chest CT reconstruction, we assess airway structure and emphysema index of the 87 smokes with normal spirometry. Five parameters related to lung function were selected as objects. Firstly, the five parameters were reduced into several principal components by principal component analysis method. Then, using these principal components as variables, the 87 high-risk people were grouped into several subtypes by k-means dynamic clustering method, and the imaging and lung function characteristics of these subtypes were analyzed. 70 cases were followed up one year later to analyze the differences in lung function and imaging changes of various subtypes. Results: Principal component analysis reduced five variables to 2 principal components, of which the first principal component mainly reflected emphysema index and the second principal component mainly reflected primary bronchial structure. Using these two principal components as variables, we divided 87 athletic patients into two subtypes by K-means cluster analysis. The first subtype: relatively severe airflow limitation, large wall area, and lumen area, and high emphysema index; The second subtype: relatively light airflow limitation, small wall area, and lumen area, and low emphysema index. A year later, a total of 70 athletic patients were followed up. As a result, compared with a year ago, the two subtypes maintained the previous heterogeneity in imaging, while FEV1/FVC decreased in lung function, and the decrease in the first subtype was more prominent (statistically significant). However, the changes in FEV1 and FEV1% Pred in these two subtypes were not statistically significant. After one year, 5 cases of the first subtype had FEV1/FVC less than 0.7, which became COPD athletic patients meeting GOLD diagnostic criteria, while no athletic patients of the second subtype had FEV1/FVC less than 0.7. Conclusion: The smokers with normal spirometry has heterogeneity in chest CT. Using imaging data and cluster analysis, the high-risk population of COPD can be divided into two subtypes, of which one subtype has a rapid decline in lung function and early occurrence of airflow restriction, requiring early intervention. However, the other subtype's lung function decreases slowly, and the urgency of intervention is not strong. The degree of airway remodeling may be the basis of heterogeneity in smokes with normal spirometry.