This study aimed to evaluate the association between adherence to maintenance medication (ie, inhaled bronchodilators, inhaled corticosteroid/long-acting beta-2 agonist [ICS/LABA] combinations, and oral therapy) and acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and related costs among patients with chronic obstructive pulmonary disease (COPD) in China.
Claims data from the hospitals of a metropolitan city in south China between January 2014 and December 2016 were obtained. Patients with COPD with ≥2 maintenance medication claims during 1 year were included. Adherence was measured by the proportion of days covered (PDC). The interaction of medication class×adherence was considered when building models.
A total of 11,708 patients met the inclusion criteria, of whom 10.8% were highly adherent (PDC≥0.8). There were significant interaction effects of drug category on hospitalized AECOPD risk (P≤0.001), hospitalized AECOPD rate (P<0.001), and 1-year hospitalized AECOPD treatment costs (P=0.012). There was a relationship between high adherence and outcomes for ICS/LABA combinations (n=3,419), ie, relative risk of hospitalized AECOPD was reduced by 34.8% (adjusted odds ratio=0.65; 95% confidence interval (CI): 0.54–0.79; P<0.001) while the frequency of hospitalized AECOPD per patient-year was reduced by 24.4% (adjusted rate ratio=0.76; 95% CI: 0.65 to 0.87; P<0.001). Mean 1-year per-patient hospitalized AECOPD costs were reduced by 37.8% (mean difference=−848 USD; 95% CI: −1435–262 USD; P<0.001). Patients taking oral mucolytics and having high adherence had worse AECOPD outcomes than patients with poor adherence.