Immunosuppressant adherence levels in kidney transplant recipients measured by electronic monitoring devices: A systematic review and meta-analysis

Background: Kidney transplantation improves survival and quality of life in patients with end-stage renal disease; however, long-term graft success depends on adherence to immunosuppressive therapy. Objective: To quantify adherence levels among kidney transplant recipients using electronic monitoring devices. Methods: PubMed, Web of Science, Scopus, and the Cochrane Library were systematically searched for studies published between 2000 and 2025. A random-effects meta-analysis was conducted including studies that assessed adherence using electronic monitoring devices. Results: Seven studies with a total of 1025 kidney transplant recipients were included. The pooled mean adherence measured using electronic monitoring devices was 94.39%. In studies with monitoring durations of three months or longer, adherence decreased to 90.50%. Substantial heterogeneity was observed across studies. Conclusion: Although electronically measured adherence appears generally high, its decline over longer monitoring periods indicates that adherence is dynamic and may decrease over time. However, these estimates should be interpreted cautiously because electronic monitoring devices cannot confirm actual medication ingestion. Furthermore, intentionally non-adherent patients may be less likely to participate in or remain engaged with electronic monitoring studies and may therefore be underrepresented, potentially leading to an overestimation of true adherence. Even modest reductions in adherence may carry important clinical consequences, underscoring the need for sustained monitoring.