Despite High Symptom Burden, Adherence to Medication Remains Low in Missouri COPD Population

With considerable social and economic burden associated with COPD, there is a need to better understand symptom burden and medication adherence in real-world settings. Seeking to do just that, a study focusing on community pharmacies in Missouri, which has a moderate to high prevalence of COPD (6.5% to 7.5%), found that patients with COPD receiving respiratory medication from the pharmacies had high symptom burden but low medication adherence.

Of the 682 patients involved in the study, the majority (60.9%) had a modified Medical Research Council score of 2 or more, indicating high symptom burden according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) classifications. The majority of these 415 patients had scores of 2 or 3 out of a maximum of 4.

Results of the COPD Assessment Test also indicated high symptom burden, with the overwhelming majority (90.2%) of patients having scores of 10 or more, and the mean score landing at 21.5. The self-administered questionnaire has a scoring system of 0-40, with 40 representing the highest symptom burden. The highest mean item score was from breathlessness and the lowest was for confidence in leaving the home.

In the previous 12 months, more than half (57.2%) of patients reported experiencing at least 2 moderate exacerbations or 1 severe exacerbation.

The patients involved in the study visited 10 independent and 16 small-chain pharmacies between October 10, 2016, and April 30, 2017. Of these patients, 465 (68.2%) reported having a formal breathing test within the prior 3 years and 251 (36.8%).

Despite the high-symptom burden of disease, the mean proportion of days covered (PDC) was 46%, indicating that patients dispensed medication approximately half of the time during the 12-month period prior to study enrollment. Less than one-third (28.7%) of patients adhered to at least 1 medication during the same period, and more than one-third of patients had poor adherence (PDC<20%).

“Reasons for low adherence observed here are unclear,” wrote the researchers. “The prevalence of obesity and the use of Medicaid were high in this population compared with COPD populations in other studies and the general population. These observations might suggest a relatively high degree of poverty, which has been associated with low adherence; however, other studies have reported a lack of association between socioeconomic status and adherence.”

There were 130 patients with forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC) of less than 0.70, of which most were classified as GOLD grade 2 (41.5%) or grade 3 (35.4%). Among these patients, the PDC was slightly higher (54%). According to the researchers, the remaining patients who had FEV₁/FVC of at least 0.70 lacked spirometric evidence of obstruction required for a diagnosis of COPD according to GOLD guidelines.

Reference:

Bollmeier S, Seaton T, Prosser T, et al. Assessment of symptom burden and adherence to respiratory medications in individuals self-reporting a diagnosis of COPD within a community pharmacy [published online April 28, 2019]. J Am Pharm Assoc. doi: 10.1016/j.japh.2019.04.017.