Medication non-adherence in chronic kidney disease: a mixed-methods review and synthesis using the theoretical domains framework and the behavioural change wheel

Medication non-adherence is a well-recognised issue in chronic diseases but data in patients with chronic kidney disease (CKD) not receiving kidney replacement therapy (KRT) remains limited. This review summarised the prevalence of medication non-adherence and assessed determinants and outcomes associated with it in adults with CKD, not on KRT. We searched PubMed, Embase, PsychInfo, Web of Science, and Cochrane (CENTRAL) for studies published until January 2020. Pooled prevalence of medication non-adherence was reported. Determinants of adherence—identified from quantitative and qualitative studies—were mapped into the theoretical domains framework and interventions proposed using the behavioural change wheel. Twenty-seven studies (22 quantitative and 5 qualitative) were included. The pooled prevalence of medication non-adherence was 39% (95% CI 30–48%). Nine studies reported association between non-adherence and outcomes, including blood pressure, disease progression, adverse events, and mortality. Modifiable determinants of non-adherence were mapped into 11 of the 14 Theoretical Domains Framework—of which, six appeared most relevant. Non-adherence decisions were usually due to lack of knowledge on CKD, comorbidities, and medications; polypharmacy and occurrence of medication side effects; changes in established routines such as frequent medication changes; higher medication cost, poor accessibility to medications, services and facilities; inadequate patient-healthcare professional communication; and forgetfulness. Using the behavioural change wheel, we identified several areas where interventions can be directed to improve medication adherence. Medication non-adherence is common in adults with CKD, not on KRT and may lead to poor outcomes. Evidence synthesis using mixed study designs was crucial in identifying determinants of non-adherence, drawing on a parsimonious approach from behaviour science. CRD42020149983.