Medicines adherence--evidence for any intervention is disappointing

Interventions to improve adherence with medicines have been studied for many years. The outcomes, both for improved adherence and clinical indicators, have not been as positive as expected or hoped for. Any improvement in adherence that may occur has not necessarily translated to improved clinical outcomes. The studies are heterogeneous, often of poor quality, with different outcomes and measures of outcome, and with ill-defined interventions, such as a lack of information on specific content of an 'educational' intervention. It appears that interventions are very resource intensive with no cost-effectiveness studies. More research is required into interventions to improve medicines adherence before more health care funding is invested in labour-intensive interventions that appear logical but are not supported by evidence from quality research.