Meta-analysis of 11,647 kidney transplant recipients finds higher risks of graft loss and rejection, highlighting the need for further research into drug-level monitoring.
High fluctuations in tacrolimus levels may be linked to an increased risk of kidney transplant failure and rejection, according to a systematic review and meta-analysis involving 11,647 adult kidney transplant recipients. The findings highlight the importance of studying variations in tacrolimus exposure to better understand long-term transplant outcomes.
The research analysed 10 studies identified through searches of MEDLINE, CENTRAL, Scopus, and Embase, covering published evidence up to October 2025. The study focused on whether high intrapatient variability (IPV) in tacrolimus levels was associated with poor outcomes after kidney transplantation.
Tacrolimus is an immunosuppressive medicine used to help prevent the body’s immune system from rejecting a transplanted organ. However, variations in drug exposure have raised concerns about their possible impact on transplant survival.
Higher Risks of Graft Loss and Rejection
The analysis found that patients with high tacrolimus IPV had more than twice the risk of death-censored graft loss compared with those with lower variability. The hazard ratio was 2.13, with a 95% confidence interval of 1.37–3.32.
High variability was also associated with an increased risk of transplant rejection, with a hazard ratio of 2.05 and a 95% confidence interval of 1.24–3.41.
However, the findings differed in consistency across outcomes. Studies examining graft loss showed considerable variation, while the results for rejection were more consistent.
The reported prevalence of high tacrolimus IPV ranged from 11% to 69%. Differences in measurement methods, thresholds, and monitoring periods may explain this wide range.
Need for Standardised Monitoring
The findings suggest that tacrolimus IPV could help identify kidney transplant recipients who may face a greater risk of graft loss or rejection. However, the researchers cautioned that the results show an association and do not prove that fluctuations directly cause these complications.
Further research is needed to establish standardised methods for measuring tacrolimus variability and to determine reliable thresholds for clinical use. Prospective studies must also assess whether incorporating IPV into routine monitoring can improve patient outcomes.
For transplant teams, the findings highlight a potential area for improving risk assessment. Until stronger evidence becomes available, tacrolimus IPV should be considered a promising research tool rather than an established standard for clinical monitoring.
For more health-related news
