Prevalence and presentation of early stage of chronic obstructive pulmonary disease in China: a national cross-sectional study

Aims: To determine current prevalence and unique characteristics of individuals with chronic obstructive pulmonary disease (COPD) stage 0, early COPD, pre-COPD, and preserved ratio impaired spirometry (PRISm), young COPD, and mild COPD in general Chinese population. Methods: Data were obtained from the China Pulmonary Health study (2012-2015), a nationally representative cross-sectional investigation with 50,991 adults aged 20 years or older. Definitions of disease status were consistent with the latest 2023 GOLD criteria. Results: The age-adjusted prevalence of COPD stage 0, early COPD, pre-COPD, PRISm, young COPD, and mild COPD were 13.44%, 1.33%, 9.54%, 4.81%, 2.41%, and 4.04%, respectively. COPD stage 0 and pre-COPD presented with higher burdens of symptoms (i.e. cough, sputum, wheeze, and dyspnea), experienced more exacerbations, and harbored multiple comorbidities (e.g. rhinitis or allergic rhinitis, chronic bronchitis, cardiovascular disease, gastroesophageal reflux disease, depression, anxiety, anemia, periodontitis, etc.). Particularly, pre-COPD exhibited more small airway dysfunction. PRISm presented with lower post-bronchodilator FEV1%pred values. Young and mild COPD had lower pre- and post-bronchodilator FEV1/FVC ratios, and more reversibilities. Over the six subgroups of population, less than 12% ever took pulmonary function test; less than 1% reported a previously diagnosed COPD; less than 15% received pharmaceutical treatment and/or oxygen therapy. Conclusions: Prevalence and presentation are varied with different criteria of early stage of disease; more attention, better management. and further research should be paid on these individuals.