Interventions for improving adherence to treatment recommendations in people with type 2 diabetes mellitus

BACKGROUND: Research suggests adherence to treatment recommendations is low. In type 2 diabetes, which is a chronic condition slowly leading to serious vascular, nephrologic, neurologic and ophthalmological complications, it can be assumed that enhancing adherence to treatment recommendations may lead to a reduction of complications. Treatment regimens in type 2 diabetes are complicated, encompassing life-style adaptations and medication intake. OBJECTIVES: To assess the effects of interventions for improving adherence to treatment recommendations in people with type 2 diabetes mellitus. SEARCH STRATEGY: Studies were obtained from searches of multiple electronic bibliographic databases supplemented with hand searches of references. Date of last search: November 2002. SELECTION CRITERIA: Randomised controlled and controlled clinical trials, before-after studies and epidemiological studies, assessing changes in adherence to treatment recommendations, as defined in the objectives section, were included. DATA COLLECTION AND ANALYSIS: Two teams of reviewers independently assessed the trials identified for inclusion. Three teams of two reviewers assessed trial quality and extracted data. The analysis for the narrative part was performed by one reviewer (EV), the meta-analysis by two reviewers (EV, JW). MAIN RESULTS: Twentyone studies assessing interventions aiming at improving adherence to treatment recommendations, not to diet or exercise recommendations, in people living with type 2 diabetes in primary care, outpatient settings, community and hospital settings, were included. Outcomes evaluated in these studies were heterogeneous, there was a variety of adherence measurement instruments. Nurse led interventions, home aids, diabetes education, pharmacy led interventions, adaptation of dosing and frequency of medication taking showed a small effect on a variety of outcomes including HbA1c. No data on mortality and morbidity, nor on quality of life could be found. AUTHORS' CONCLUSIONS: Current efforts to improve or to facilitate adherence of people with type 2 diabetes to treatment recommendations do not show significant effects nor harms. The question whether any intervention enhances adherence to treatment recommendations in type 2 diabetes effectively, thus still remains unanswered.