ABSTRACT
Individuals’ health-risky behaviours are estimated to account for 50 per cent of preventable deaths and billions of dollars in health-care expenses. Adherence to medical treatments and healthy lifestyle behaviours is the key link between patient behaviour and health outcomes; therefore, improving adherence is necessary for reducing chronic disease burden and lowering health-care costs. The role of researchers in addressing these societal problems is in identifying key predictors of non-adherence and developing interventions to promote adherence to medications and health lifestyle behaviours. This article defines treatment adherence, presents data on the prevalence of non-adherence to different treatment types and in different populations, summarises research theory and evidence regarding adherence predictors and interventions, and highlights remaining gaps and innovative approaches for future adherence research. Predictors of non-adherence and targets of interventions include patients’ beliefs about treatments, experiences with treatments, self-efficacy for enacting treatments, routines/habits for enacting treatment(s), access and ability to enact treatment(s), and concordance with their medical providers regarding aspects of their illness and the recommended treatment(s). These constructs are represented to different degrees in commonly used theories, including the common-sense self-regulation model, the health belief model, the theory of planned behaviour, and self-determination theory. Adherence is primarily assessed via self-reports, medical records (e.g. pharmacy counts, gym visits), and objective monitors (e.g. electronic monitoring pill bottles, accelerometers, or pedometers). Interventions have shown varying but generally small effects, particularly for long-term adherence/maintenance. Promising avenues for research include determining strategies for automating access, enactment of treatments through habit formation and technology-driven or technology–facilitated means, and enhancing patient–provider communication.
