Abstract Medication adherence is critical for optimal glycaemic management and the prevention of complications in type 2 diabetes mellitus. Despite its importance, non-adherence remains a prevalent issue, with global estimates suggesting that approximately 38% of people with type 2 diabetes do not take their medications as prescribed, although estimates vary widely due to a range of patient-related, socioeconomic, condition-related (e.g. chronicity, severity of comorbidities) and healthcare system factors. This review synthesises the current evidence on the prevalence of non-adherence in type 2 diabetes, as well as risk factors and clinical and economic consequences, and evaluates interventions designed to improve adherence in this population. Medication non-adherence is associated with increased HbA 1c levels and risks of micro- and macrovascular complications, hospitalisation and mortality, while also incurring substantial healthcare costs. Methods for assessing medication adherence range from subjective self-report tools to objective measures such as biochemical testing, which are gaining prominence in both research and clinical practice. Numerous interventions to increase medication adherence have been investigated, including educational, technological, pharmacist-led, behavioural and financial strategies and fixed-dose combination (FDC) therapies. While interventions such as pharmacist-led care and FDC therapies are beneficial, outcomes from technology-based and motivational strategies remain mixed. Shared decision making and behavioural interventions, such as cognitive behavioural therapy, may provide additional benefits, particularly for individuals with multiple long-term conditions or psychological comorbidities. Multifaceted interventions tailored to individual barriers and sustained over time appear most effective. Given the significant impact of non-adherence on both patient outcomes and healthcare systems, future research is needed to design personalised, multicomponent interventions that are scalable and equitable across diverse healthcare settings. Graphical Abstract
Highton et al. (2025) studied this question.