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Cost of medication adherence and persistence in type 2 diabetes mellitus: a literature review

Authors Kennedy-Martin T, Boye KS, Peng X

Received 9 March 2017

Accepted for publication 16 May 2017

Published 30 June 2017 Volume 2017:11 Pages 1103—1117


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Editor who approved publication: Dr Johnny Chen

Tessa Kennedy-Martin,1 Kristina S Boye,2 Xiaomei Peng2

1Kennedy-Martin Health Outcomes Ltd, Brighton, UK; 2Global Health Outcomes, Eli Lilly and Company, Indianapolis, IN, USA

Purpose: To explore published evidence on health care costs associated with adherence or persistence to antidiabetes medications in adults with type 2 diabetes mellitus (T2DM).
Methods: Primary research studies published between January 2006 and December 2015 on compliance, adherence, or persistence and treatment in patients with T2DM that document a link with health care costs were identified through literature searches in bibliographic databases and 2015 abstract books for relevant DM congresses. Results were assessed for relevance by two reviewers. The review was part of a larger overview evaluating the impact of adherence and persistence on a range of clinical and economic outcomes; only findings from the cost element are reported herein.
Results: A total of 4,662 de-duplicated abstracts were identified and 110 studies included in the wider review. Of these, 19 reported an association between adherence (n=13), persistence (n=5), or adherence and persistence (n=1), and health care costs. All studies were retrospective, with sample sizes ranging from 301 to 740,195. Medication possession ratio was the most commonly employed adherence measure (n=11). The majority of adherence studies (n=9) reported that medication adherence was associated with lower total health care costs. Pharmacy costs were often increased in adherent patients but this was offset by beneficial effects on other costs. Findings were more variable in persistence studies; three reported that higher pharmacy costs in persistent patients were not sufficiently offset by savings in other areas to result in a reduction in total health care costs.
Conclusions: Few studies have evaluated the relationship between adherence, persistence, and health care costs in T2DM. However, it has been consistently shown that medication nonadherence increases health care costs, suggesting that cost savings from better adherence could be substantial. Available data support the economic case for identification of strategies that facilitate improved medication adherence in patients with T2DM.

Keywords: adherence, persistence, type 2 diabetes mellitus, costs, review 

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