Various Methods Used in COPD Medication Adherence Assessments, Review Says

Authors used various assessment methods to evaluate medication adherence in patients with chronic obstructive pulmonary disease (COPD), according to a review published in European Respiratory Review.¹

The researchers explained that pharmacological treatment of patients with COPD reduces symptoms, along with exacerbation frequency and severity. Consequently, the 2023 Global Initiative for Chronic Obstructive Lung Disease report highlighted “the importance of adherence as an essential aspect to optimize the benefits of drug therapy.”

However, the researchers noted the lack of a uniform method used to assess patient adherence to COPD medications. Because of this, they conducted a systematic review of select studies to describe current methods used to assess adherence in patients with COPD and to evaluate the reporting of influential variables, namely inpatient stays, drug substitutions, early refills, and dose switches.

To do so, they searched MEDLINE, Web of Science, and Embase for relevant peer-reviewed studies on October 10, 2022. They explained that medication adherence was defined based on the Ascertaining Barriers to Compliance taxonomy for medication adherence.² Consequently, the researchers defined initiation as “the dispensing of medication in a predefined period of time after prescribing,” implementation as “the extent to which a patient uses medication as recommended over a specific period of time,” and persistence as “the time from initiation to discontinuation of the therapy.”

Two reviewers independently screened article titles and abstracts.¹ Those chosen to move forward received a full-text evaluation using Rayyan software. Once they determined which articles to use, the researchers evaluated the quality of each with the National Institutes of Health (NIH) quality assessment tool; they explained that they did not remove the “poor quality” studies since they aimed to review all methods currently being used.

lung illustration | Image credit: yodiyim - stock.adobe.com

The researchers initially identified 7144 eligible studies, which they narrowed down to 152 . After adding 8 from their manual search of the reference and citation lists, their population consisted of 160 studies published between 1999 and 2022. Across all studies, the population consisted of 80 patients from North America, 68 from Europe, 7 from Asia, and 6 from Oceania.

With the NIH quality assessment tool, the researchers classified 70.6% (113 of 160) of the studies as good quality. Also, they found that most of the studies assessed implementation (84.4%) or persistence (28.1%), with 24 studies evaluating both (15.0%). Only 4 studies assessed initiation (2.5%). Throughout the analyzed studies, the researchers explained that 1 method was used to measure initiation, 7 for persistence, and 43 for implementation.

The researchers noted that only about 11% (18 of 160) of the included studies reported on the selected variables. They found the influence of medication substitutions to be estimated in 4 of 5 included studies; the studies either limited their assessment to a specific drug (51 of 127) or analyzed all medications together (41 of 127). The researchers explained that some authors described the impact of medication switches (41 of 127) while others (65 of 150) made it less clear whether dose switching affected adherence assessment.

As for the other variables, the researchers found that 34% of studies reported inpatient stays, either by including it in the calculation formula, adjusting the study design, or acknowledging it as a limitation. Additionally, 49 of 116 studies assessed the impact of early refills, some authors mentioning it as a possible influential factor, and others made assumptions about patients not retrieving medication before their stock ran out.

The researchers also acknowledged their study’s limitations, one being that they only included studies written in English. Additionally, they did not consider studies published after October 11, 2022. To improve upon their findings, the researchers recommended future research on the impact of key variables in COPD adherence.

“More attention to the reporting of the adherence method and influencing variables is desirable,” the authors concluded. “Where there is lack of information about an influencing variable, authors should acknowledge this limitation.”

References

1. Vauterin D, Van Vaerenbergh F, Vanoverschelde A, Quint JK, Verhamme K, Lahousse L. Methods to assess COPD medications adherence in healthcare databases: a systematic review. Eur Respir Rev. 2023;32(169):230103. doi:10.1183/16000617.0103-2023

2. Bernardo C, Tosin MHS, Almada M, et al. Translation and cross-cultural adaptation of the ABC taxonomy for medication adherence into Portuguese - Updating patients into people. Res Social Adm Pharm. 2023;19(4):653-659. doi:10.1016/j.sapharm.2022.12.010