Understanding adherence to medications in type 2 diabetes care and clinical trials to overcome barriers: a narrative review

Abstract

Aim:

To identify factors affecting adherence to medications in type 2 diabetes (T2D) care and clinical trials.

Background:

Adherence to medication is associated with better patient outcomes, lower healthcare costs, and improved quality and robustness of trial data. In T2D, non-adherence to regimens may compromise glycemic, blood pressure and lipid control, which can, in turn, increase morbidity and mortality rates.

Design:

A literature search was performed to identify studies reporting adherence to medications and highlighting specific adherence challenges/approaches in T2D. The search was limited to clinical trials, comparative studies or meta-analyses, reported in English with a freely available abstract.

Data source:

MEDLINE (31 December 2008 to 31 December 2013).

Review methods:

Studies not reporting adherence to medications or highlighting adherence challenges/approaches in T2D, presenting only self-reported adherence or including fewer than 100 patients were excluded. Eligible reports are discussed narratively.

Results:

Factors identified as having a detrimental impact on adherence were smoking, depression and polypharmacy. Conversely, increased convenience (e.g. pen compared with vial and syringe; medication supplied by mail order vs. retail pharmacy) was associated with better patient adherence, as were interventions that increased patient motivation (e.g. individualized, nurse-led consultation) and education.

Conclusions:

Medication adherence is influenced by complex and multifactorial issues, which can include smoking, depression, polypharmacy, convenience of obtaining and administering the medication, patient motivation and education. We recommend simplifying treatment regimens, where possible, improving provider–patient communication, and providing support and education to increase medication adherence, with a view to improving patient outcomes and clinical trial data quality.

Keywords: :

• Adherence
• Antidiabetic
• Antihyperglycemic
• Compliance
• Diabetes mellitus
• Drug
• Literature review
• Medication

Transparency

Declaration of funding

Novo Nordisk funded the conduct of the literature search, writing assistance and proofreading of the article.

All of the authors contributed to the design of the literature review and interpretation of its findings, critically revised drafts of the manuscript and provided final approval of the uploaded version.

Declaration of financial/other relationships

M.T. has disclosed that she has received personal fees from Novo Nordisk for consultancy on the Patient Retention Panel and as a National Study Coordinator for LEADER (a GLP-1 analog clinical trial) conducted by Novo Nordisk. She also received non-financial support in the form of technical writing, editing and review for scientific accuracy. S.C. has disclosed that she has received honoraria for consultancy on the Patient Retention Panel for LEADER (a GLP-1 analog clinical trial) conducted by Novo Nordisk. L.B. has disclosed that she has received honoraria for lectures, travel support and consultancy services from pharmaceutical companies manufacturing diabetes treatments, including AstraZeneca, Bristol Myers Squibb, Eli Lilly, Merck, BD, Abbott, Lifescan, Janssen, Bayer and Novo Nordisk. She serves on GLP-1 analog clinical trial and insulin committees for Novo Nordisk and Sanofi.

CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgments

The authors are grateful to Watermeadow Medical for writing assistance in the development of this manuscript. This assistance was supported by Novo Nordisk, which also had a role in the review of the manuscript for scientific accuracy.