Abstract
Adherence therapy has been shown to be an effective adjunct treatment in long-term conditions including hypertension. The purpose of this study is to review and critically appraise evidence on the effectiveness of adherence therapy as an intervention in adults with type 2 diabetes. A systematic search of clinical trials published between 2005 and January 2020 in databases was undertaken in October 2018 and updated in August 2020. Inclusion criteria were any clinical trials where the population under investigation was adults with type 2 diabetes and the experimental intervention was adherence therapy. Version 2 of the Cochrane risk of bias was used to determine the quality of the included studies. No studies met our inclusion criteria. However, four studies that we excluded at full text screening tested some of the components (e.g., problem solving) of adherence therapy. As is recommended when reporting empty reviews, those studies were synthesized to determine if useful information can be extracted. That no trials of adherence therapy have been reported in type 2 diabetes establishes a potentially important gap in knowledge. This review was registered in PROSPERO (registration number: CRD42019115216) after the initial searches were completed.