Risk factors associated with chronic obstructive pulmonary disease severity among adults: a hospital-based cross-sectional study in Ningbo, China (2022–2025)

Background: Chronic obstructive pulmonary disease (COPD) remains a major public health burden. Understanding the distribution of demographic, clinical, and socioeconomic characteristics across severity stages may support improved disease management. This study examined characteristics associated with COPD severity among adults aged 60–80 years in a hospital-based screening cohort in Ningbo, China. Methods: A cross-sectional analysis was conducted from January 2022 to December 2025 among 18,832 spirometry-confirmed COPD patients identified through a hospital-based screening program. COPD severity was classified according to the 2023 Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. Group differences were evaluated using χ² tests for categorical variables and Welch’s analysis of variance (ANOVA) for continuous variables. Factors associated with severity stage were examined using ordinal logistic regression. Results: Most patients were classified as GOLD stage I or II. In univariate analyses using χ² tests and Welch’s ANOVA, several demographic, symptom-related, and socioeconomic characteristics differed significantly across severity stages. In multivariable ordinal logistic regression, older age [adjusted odds ratio (aOR) =1.015, 95% confidence interval (CI): 1.008–1.023], higher COPD Screening Questionnaire (SQ) score (aOR =1.03, 95% CI: 1.02–1.04), higher COPD Population Screener (PS) score (aOR =1.20, 95% CI: 1.17–1.23), and a history of frequent long-lasting lower respiratory infections (aOR =1.39, 95% CI: 1.27–1.51) were positively associated with higher severity stages. Female sex (aOR =0.87, 95% CI: 0.81–0.94), higher educational attainment (aOR =0.75, 95% CI: 0.65–0.86), and higher socioeconomic status (aOR =0.80, 95% CI: 0.74–0.86) were inversely associated with severity classification. Conclusions: In this hospital-based screening cohort, COPD severity varied systematically across demographic, symptom-related, and socioeconomic characteristics. These findings describe stage-related gradients within the screened population and may inform targeted management strategies.