Nonadherence to medical plans remains a challenge for health care professionals and scientists, as their efforts to improve and explain patients’ adherence appear to be ineffective. In fact, a study by the World Health Organization found that only 50% of the patients in developed countries adhere to their treatment plans. This degree of nonadherence results in a high number of patients that do not get the maximum benefits of medical treatment, which is associated with high health care costs, lower quality of life, and poor health outcomes. Nonadherence to medical plans is a public health problem that affects all people in general, but with particular significance in older adults, as they show the cooccurrence of multiple chronic diseases and conditions.

Many interventions to improve adherence have been described in the literature, some of them with good results; however, most interventions seem to fail in their aims. Moreover, most interventions associated with adherence improvements are not associated with improvements in other outcomes, such as biomarkers, morbidity, mortality, quality of care, quality of life, patient’s satisfaction, health care utilization, and costs. In fact, adherence rates remained unchanged in the last decades. The reasons for the slow progress seem to be the lack of comprehensive theoretical models to explain nonadherence and to explain the potential success of a given intervention.

In this issue, we intend to collect and review new data on adherence to medical plans, with particular focus on intervention tools that could be used in clinical practice, and to address some identified gaps in adherence and prescription issue.

We are pleased to invite researchers and clinicians to contribute original research and review papers.

Potential topics include, but are not limited to:

• Epidemiological studies on adherence to medical plans
• Interventions studies to improve adherence and prescription in different chronic conditions
• Description of new and innovative tools to improve adherence and prescription
• Description of new and innovative methods to monitor interventions outcomes
• Theories to predict and explain nonadherence adequately
• Socioeconomic impact of interventional studies to improve adherence
• Health policies
• National and international approaches to improve adherence