Association of adherence to long-acting inhaler use for initial treatment of chronic obstructive pulmonary disease and acute exacerbation: A retrospective cohort study

Abstract Background This study aimed to determine the effect of long-acting inhaler medication use adherence on acute exacerbations in treatment-naïve patients with chronic obstructive pulmonary disease (COPD) from healthcare claim data. Methods Using the Korean Health Insurance Review and Assessment Service database from July 2015 to December 2016, patients with COPD aged ≥ 40 who had started using long-acting inhalers were enrolled and observed for 6 months. Patients who were prescribed long-acting inhalers and had been hospitalized or visited emergency department (ED) for COPD 6 months before the first prescription were excluded. Medication adherence was indirectly measured by the medication possession ratio (MPR) based on the adherence (MPR ≥ 80%) and non-adherence (MPR < 80%) groups. Results A total of 3,959 patients were enrolled: 60.4% and 39.6% in the adherence and non-adherence groups, respectively. The risk factor analysis showed that the relative risk of acute exacerbation in the non-adherence group was 1.58 (95% confidence interval [CI] 1.25 − 1.99) in comparison to the adherence group. The logistic regression analysis after adjustment for patient-related variables demonstrated that the relative risk of acute exacerbation in the non-adherence group vs. the adherence group was 1.68 (95% CI 1.32 − 2.14) in terms of the number of inhalers used. Good adherence positively influenced the decreased rate in acute exacerbation for patients with COPD. Conclusions The risk of acute exacerbation of COPD requiring hospitalization or ED visit was low in the long-acting inhaler adherence group, suggesting that medication adherence imposes a reduction effect on acute exacerbation even in the initial management among treatment-naïve patients.