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

OBJECTIVE: 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. METHOD: 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. RESULTS: 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. CONCLUSION: 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. PROSPERO REGISTRATION: CRD42020149983.