Validation of tacrolimus equation to predict troughs using genetic and clinical factors

Aim: Tacrolimus is an immunosuppressant used in transplantation. This article reports the validation of the authors recently developed genetics-based tacrolimus equation that predicts troughs. Methods: Validation was performed in an independent cohort of 795 kidney transplant recipients receiving tacrolimus. The performance of the equation to predict initial troughs was assessed by calculating the bias and precision of the equation. For all troughs in the first 6 months post-transplant, a comparison was made between the troughs predicted using the equation versus those predicted using a basic apparent clearance model with no covariates. Results: For initial troughs, the equation had a low bias (0.2 ng/ml) and high precision (1.8 ng/ml). For all troughs, the equation predicted troughs significantly better than the basic apparent clearance model. Conclusion: The tacrolimus equation had good bias and precision in predicting initial troughs and performed better than a basic apparent clearance model for all the troughs. Original submitted 5 April 2012; Revision submitted 25 May 201.