Adherence to long-acting inhaled therapies among patients with chronic obstructive pulmonary disease (COPD)

Background: Long-acting inhaled medications are an important component of the treatment of patients with chronic obstructive pulmonary disease (COPD), yet few studies have examined the determinants of medication adherence among this patient population. Objective: We sought to identify factors associated with adherence to long-acting beta-agonists (LABA) and inhaled corticosteroids (ICS) among patients with COPD. Methods: We performed secondary analysis of baseline data collected in a randomized trial of 376 Veterans with spirometrically confirmed COPD. We used electronic pharmacy records to assess adherence, defined as a medication possession ratio of ≥0.80. We investigated the following exposures: patient characteristics, disease severity, medication regimen complexity, health behaviors, confidence in self-management, and perceptions of provider skill. We performed multivariable logistic regression, clustered by provider, to estimate associations. Results: Of the 167 patients prescribed LABA, 54% (n = 90) were adherent to therapy while only 40% (n = 74) of 184 the patients prescribed ICS were adherent. Higher adherence to LABA and ICS was associated with patient perception of their provider as being an "expert" in diagnosing and managing lung disease For LABA: OR = 21.70 (95% CI 6.79, 69.37); For ICS OR = 7.93 (95 CI 1.71, 36.67). Factors associated with adherence to LABA, but not ICS, included: age, education, race, COPD severity, smoking status, and confidence in self-management. Conclusions: Adherence to long-acting inhaled medications among patients with COPD is poor, and determinants of adherence likely differ by medication class. Patient perception of clinician expertise in lung disease was the factor most highly associated with adherence to long-acting therapies.