Background: No studies have examined adherence or persistence to long-acting anticholinergics (LAAC) treatment episodes in patients with chronic obstructive pulmonary disease (COPD).
Objective: To estimate 1-year adherence and 5-year persistence to LAAC during treatment episodes, and the likelihood of initiating a subsequent treatment episode.
Methods: A retrospective cohort of LAAC-treated COPD patients was reconstructed from Quebec databases. A treatment episode was initiated at cohort entry, defined as the first LAAC prescription date on/after the first COPD diagnosis date recorded between October 1, 2003, and March 31, 2014. We identified a subsequent treatment episode up to 5 years after the end of the episode initiated at cohort entry. We measured adherence as the proportion of days covered over 1 year. Persistence was defined as prescription renewal within 90 days of the previous prescription and was plotted using Kaplan-Meier curves over 5 years. The 5-year hazard and cumulative incidence of initiating a subsequent episode were estimated with survival analyses. We compared adherence and persistence between the treatment episodes using t and log-rank tests.
Results: The cohort included 113 435 COPD patients. Adherence and persistence to LAAC were significantly lower in the subsequent treatment episode (55% vs 63%; P < 0.0001). The likelihood of initiating a subsequent episode was greatest immediately after the cessation of the initial episode, with 59% of patients starting a subsequent episode within 1 year.
Conclusion: Adherence and persistence to LAAC were lower in the subsequent treatment episode. Interventions should be offered quickly after LAAC cessation.
Keywords: adherence; administrative databases; chronic obstructive pulmonary disease; long-acting anticholinergics; persistence; treatment episode.