Figure 4. (A) Subgroup analysis of SABDs. (HRs were adjusted for age, sex, income level, comorbidities, exacerbation frequency of COPD, exacerbation frequency of HF, Charlson Comorbidity Index, urbanization level and medications; medications were analyzed as time-dependent covariates, time period: 3 months). (B) Subgroup analysis of LABAs alone. (C) Subgroup analysis of ICSs alone.