Evaluation of Tacrolimus Trough Level in Patients Who Developed Post-transplant Diabetes Mellitus After Kidney Transplantation: A Retrospective Single-Center Study in Saudi Arabia.

Abstract Background Post-transplant diabetes mellitus (PTDM) is a complication after kidney transplantation. Studies showed an association between high trough levels of tacrolimus FK506 and PTDM. This study aims to investigate the association between FK506 trough levels during the first year after kidney transplant and the incidence of PTDM. Methods This retrospective study included adult kidney transplant patients who were not diabetic before transplantation from 2011 to 2014. The analysis evaluated FK506 trough levels at different time points post-transplant, as well as other variables to determine whether they were associated with PTDM. Results The cumulative incidence of PTDM was 22.5% with a median time to PTDM diagnosis of 10 months. PTDM patients had higher first FK506 (ng/mL) levels (P = .001), and more patients in the PTDM group had FK506 level >10 ng/mL during the first 3 months (P = .004). After 12 months of transplant, PTDM patients had higher body mass index (BMI) 28.3 ± 6.9 kg/m2 compared to non-PTDM patients 26.4 ± 6.7 kg/m2 (P = .015). Binary logistic regression analysis showed that age ≥40 years (odds ratio [OR] = 2.75, P = .004), BMI ≥25 kg/m2 (OR = 2.04, P = .040), and FK506 level ≥10 ng/mL during the first 3 months (OR = 2.65, P = .009) were significantly related to PTDM development. Conclusion Patients with FK506 trough level >10 ng/mL during the first 3 months after transplantation are at higher risk of PTDM, especially in patients >40 years of age and/or who are overweight. These results may strengthen the notion that there is a connection between high FK506 trough levels and PTDM development.