Non-adherence to immunosuppressive medications in kidney transplant recipients- a systematic scoping review

Rejection and graft failure remain common in kidney transplant recipients. Non-adherence to immunosuppressive medications is considered a major contributary factor to reduced long-term graft survival, particularly in younger people. Improvements in clinical practice based on adherence studies has been minimal. Joanna Briggs' Institute Methodology was used. MedlineALL, Embase, Web of Science Core Collection and Scopus databases were searched from January 2000 through to December 2023. Abstract and full text reviews were undertaken independently by two reviewers. Data was collated using a pre-designed extraction tool. 359 articles met the inclusion criteria. Non-adherence was commonly defined using self-reported questionnaires or pharmacy re-fill rates. Prevalence of non-adherence varied widely. There was little correlation between method of measurement and reported rates of non-adherence. Despite younger age being identified as a risk factor for non-adherence, pooled reported prevalence did not differ significantly in studies reporting prevalence in children, adolescents, or young adults vs. older adults (36.0 % vs. 34.0 %). Interventional studies to detect or improve adherence are highly heterogenous, often report small effects and are limited by the lack of gold-standard methods to measure adherence. This scoping review outlines the complexities of non-adherence to immunosuppressive medications among kidney transplant recipients, highlighting significant variability in adherence definitions, measurements, and intervention efficacy. Reported non-adherence rates vary widely (2–89 %), underscoring the need for standardisation of the definition of non-adherence in research. Findings suggest that non-adherence to immunosuppressive medication is driven by a mix of demographic, psychosocial, and transplant-specific factors. Future research should prioritise standardised definitions of adherence, validated tools to measure adherence, and focus on clinically significant outcomes in non-adherent populations to develop meaningful, impactful interventions for long-term patient benefit. •Non-adherence to immunosuppressive medications is high.•There is currently no gold-standard method to define or measure adherence.•Evidence base for interventions to improve adherence remains weak.