Older age, more maintenance inhalers linked to high inhaled COPD medication adherence

Key takeaways:

• Less than 40% of the studied veteran cohort were adherent to their inhaled COPD medications.
• Adherence was found via self-report and pharmacy refill data.
• COPD inhaler beliefs impacted self-reported adherence.

Factors linked to better inhaled COPD medication adherence in veterans included older age, a higher number of maintenance inhalers used and chronic prednisone use, according to results published in Annals of the American Thoracic Society.

“Adherence to inhaled COPD medications is a complex topic related to medication-specific factors and variables contributing to unintentional and intentional nonadherence,” Andrew M. Pattock, MD, cardiology fellow at the University of Washington, and colleagues wrote.

Using data from a prospective observational cohort study, Pattock and colleagues conducted a cross-sectional analysis of 269 veterans (mean age, 69.6 years; 96.3% men; mean FEV₁, 43.1% predicted) with COPD to determine the impact sociodemographic characteristics, clinical characteristics and medication beliefs have on maintenance inhaler adherence.

Researchers collected data on patients’ sociodemographic and clinical characteristics through questionnaires. To capture medication beliefs, the Beliefs about Medicines Questionnaire (BMQ) was used.

Adherence was self-reported by each veteran and measured via the Adherence to Refills and Medications Scale (ARMS). Additionally, the ReComp score, which was based on pharmacy refill data, was used to measure pharmacy-based adherence.

Many of the veterans used either a combination inhaled corticosteroid/long-acting beta agonist inhaler (69.5%) or a long-acting muscarinic antagonist maintenance inhaler (67.3%), according to researchers.

When measuring inhaled COPD medication adherence through ARMS, 38.3% of veterans reached adherence, and the same was true when using ReComp scores, with 38.3% of veterans deemed adherent. Adherence in both ARMS and ReComp was achieved by 17.8% of the total cohort.

Factors linked to higher adherence according to the ARM scale in a multivariable linear regression model adjusted for 11 significant variables (found in a prior analysis adjusted only for study site) included age increases by 10 years and more maintenance inhalers used.

Researchers continued to observe a relationship between a higher number of maintenance inhalers used and higher adherence, this time according to ReComp, in a model adjusted for five significant variables. In this model, there was also a link found between chronic prednisone use and higher ReComp adherence.

Switching to medication beliefs, there was a significant relationship between elevated COPD-specific BMQ concerns scores and lower ARMS adherence, whereas BMQ score was not significantly linked to ReComp adherence.

Researchers noted that the concerns centered around medication safety and “poor understanding of the necessity of regular maintenance inhaler use.”

“Pharmacy refill and self-report adherence may measure distinct aspects of adherence and be affected by different factors,” Pattock and colleagues wrote. “Understanding these differences may help researchers and clinicians generate hypotheses for future adherence work and improve inhaled medication adherence in COPD.”