Proportions and risk factors of chronic obstructive pulmonary disease and preserved ratio impaired spirometry, and association with small airway disease, in the screening positive older population from china: a cross-sectional study

Abstract

Abstract Background Early diagnosing Chronic Obstructive Pulmonary Disease (COPD) is relatively difficult. Therefore, the concepts of preserved ratio impaired spirometry (PRISm) and small airway disease (SAD) were proposed, expecting to achieve early diagnosis for COPD. Besides, the occurrence of COPD is positively related to age. However, the relation among COPD, PRISm, and SAD still requires clarification. Thus, we estimated the proportions and risk factors of COPD and PRISm in the screening positive participants, and searched the methods of early diagnosing COPD through the indicators of SAD. Methods A total of 53641 residents aged more than 60 years old from Shaoxing City, Zhejiang Province, China, completed a series of screening projects. And 2327 of screening positive participants ultimately finished bronchodilator tests. The data were statistically analyzed to figure out the proportions and risk factors of COPD and PRISm, and the efficacy of early diagnosing COPD by the indicators of SAD. Results Totally 2229 screening positive participants were included, the proportion of PRISm was 6.3% (141/2229), and of COPD was 78.2% (1743/2229). The results of statistical analysis showed that COPD patients were more likely to be smokers, males, older, and with higher questionnaire scores. Additionally, COPD patients had lower maximal mid-expiratory flow (MMEF), forced expiratory flow (FEF)75pred, and FEF50pred. And it was found that male sex and the presence of respiratory symptoms might lead to COPD and PRISm. Also, the methods of early diagnosing COPD by the indicators of SAD might be acceptable. Conclusion There is a close relation between COPD and decreased small airway function (SAF) among the participants included. Age, smoking, male sex, worse SAF, and respiratory symptoms might cause the progressing from normal people to PRISm, then to COPD patients. Besides, early diagnosing COPD by the indicators of SAD might be feasible. In the future, early diagnosis for COPD requires further research.