Sociodemographic Determinants of Hospitalized Exacerbations in Exposure-Defined COPD Phenotypes: A Nationwide Prospective Cohort Study in China.

Purpose: Chronic obstructive pulmonary disease (COPD) a major cause of morbidity, hospitalization, and healthcare burden worldwide and is increasingly recognized as a heterogeneous syndrome with diverse environmental and socioeconomic determinants. We aimed to identify phenotype-specific determinants of hospitalized exacerbations and annual total length of hospital stay (LHS) in smoking and non-smoking COPD. Patients and Methods: We analyzed 3,913 COPD patients from a nationwide multicenter prospective cohort in China, stratified by smoking status. Hospitalized exacerbations at baseline and during one-year follow-up, as well as LHS, were assessed. Multivariable logistic regression and ordinal logistic regression models were used to estimate adjusted odds ratios (ORs) for hospitalized exacerbations and annual total LHS within each subgroup. Results: Among 3,913 participants, 1,709 (43.7%) had non-smoking COPD and 2,204 (56.3%) had smoking-related COPD. During follow-up, 28.0% of non-smokers and 29.9% of smokers experienced hospitalized exacerbations. Rural residence, larger household size, and prior hospitalizations in the preceding year were consistently associated with hospitalized exacerbations and longer annual total LHS in both groups. Biomass exposure was independently associated with hospitalized exacerbations among non-smoking patients but not among smokers after full adjustment. Low body mass index (BMI) was associated with increased risk in non-smoking COPD. Findings were consistent across baseline and prospective analyses, as well as binary and ordinal outcome models. Conclusion: In China, rural residence, larger household size, and prior exacerbation history were common determinants of hospitalized exacerbations and longer annual total LHS in patients with COPD, while biomass exposure and low BMI exerted stronger effects in non-smoking COPD.