Many Patients With COPD Found to Have Poor Adherence to Long-Acting Inhalers

Most patients with chronic obstructive pulmonary disease (COPD) have poor adherence to long-acting inhalers, according to a study published in Patient Preference and Adherence.

To treat COPD, the Global Initiative for Chronic Obstructive Lung Disease recommends long-acting inhaler therapy. Despite this being a popular treatment, researchers in China discovered through this cross-sectional study that most patients with COPD had poor adherence to inhalers.

The researchers conducted this study from November 2020 to February 2021, enrolling patients 40 years and older with spirometric confirmation of COPD who used any inhaler for more than 1 month. They noted that their study excluded those diagnosed with other chronic respiratory diseases and those who were unable to communicate. As a result, the study population consisted of 246 patients with COPD who used dry powder or soft mist inhalers. The researchers assessed patients’ adherence to their inhalers with the Medication Adherence Scale (MARS), which consists of questions based on negative statements to limit social desirability bias.

MARS responses were scored on a 5-point Likert scale, ranging from always (1 point) to never (5 points), and the total was calculated as the mean of 10 specific scores. Researchers considered a MARS score greater than 4.5 as good adherence and a score less than 4.5 as poor adherence. They found that, of the 246 patients within their population, 153 patients had poor adherence (62.2%) and 93 had good adherence (37.8%); the mean (SD) score was 3.97 (0.83).

Physicians commonly use 3 main drug classes to manage COPD: long-acting β-adrenoceptor agonists (LABA), long-acting muscarinic antagonists (LAMA), and inhaled corticosteroids (ICS). The researchers explained that they divided the data into ICS/LABA and LAMA subgroups based on their pharmacological effects to analyze whether there was a difference in patient adherence based on the different drug categories.

They found that more patients using LAMA drugs had good inhaler adherence (χ² = 4.26; P = .04). Specifically, adherence was better among patients who used a tiotropium bromide spray compared with an inhaled tiotropium bromide powder.

The researchers also examined how patients’ different demographic characteristics, disease characteristics, and medication regimens affected adherence. The information collected from patients included gender, weight, education level, economic status, duration of illness, and number of hospitalizations due to acute exacerbations of COPD in the last year.

Of the population, 82.1% were male, 58.9% had a smoking history, and 73.6% had 2 or more acute exacerbations in the previous year. The mean (SD) age was 70.9 (9.6) years, and the mean (SD) COPD duration was 7.8 (6.6) years. Researchers found statistically significant differences (P < .05) in the population’s educational backgrounds, severity of airflow obstruction, duration of illness, and moderate or severe exacerbation history in the past year. Of these characteristics, they found that patients’ educational backgrounds and their duration of illness affected inhaler adherence (P < .05).

“Patients with poor adherence to inhalers generally had a longer COPD course of disease in our study,” the authors wrote. “With the prolongation of disease and the repeated use of inhaled preparations, their expectations for using inhalers to control the progression of the disease may decline, resulting in being reluctant to take medication as prescribed or even refusing medication.”

To ensure that more patients with COPD adhere to their inhalers, the researchers encouraged physicians to personalize care plans.

“Medical personnel should focus on the disease itself and the importance of medication adherence, implement medication education covering the whole period and strengthen follow-up of patients to track their condition and medication use, thus improving adherence with inhaler use and improving the quality of life of patients with stable COPD,” the authors wrote.

Researchers identified several limitations within their study, one being that they did not complete a logistic regression analysis due to not including several patient factors that affect inhaler adherence. Also, because patient reports dictated MARS scores, researchers hypothesized that patients may have overestimated medication adherence, perhaps due to recall issues caused by old age. Lastly, the researchers noted that the small sample size limited their study.

However, “the relevant results can still be used as baseline data to provide a reference for further regulating stable COPD management and improving patients’ treatment adherence,” the authors concluded.

Reference

Tan X, Liu S, Huang L, et al. Correlation analysis of the therapy adherence to long-acting inhalers among patients with stable COPD. Patient Prefer Adherence. 2023;17:1467-1475.doi:10.2147/PPA.S413948