Monitoring Tacrolimus Trough Concentrations During the First Year After Kidney Transplantation: A National Retrospective Cohort Study

Background: There is a lack of data in the literature on the evaluation of tacrolimus (TAC) dosage regimen and monitoring after kidney transplantation (KT) in Kuwait. The aim of the present study was to evaluate TAC dosing in relation to the hospital protocol, the achievement of target TAC trough concentration (C(0)), the prevalence of TAC side effects (SEs), namely, posttransplant diabetes mellitus (PTDM), denovo hypertension (HTN), and dyslipidemia, and factors associated with the occurrence of these SEs among KT recipients. Methods: A retrospective study was conducted among 298 KT recipients receiving TAC during the first year of PT. Descriptive and multivariate logistic regression analyses were used. Results: The initial TAC dosing as per the local hospital protocol was prescribed for 28.2% of patients. The proportion of patients who had C(0) levels within the target range increased from 31.5 to 60.3% during week 1 through week 52. Among patients who did not have HTN, DM, or dyslipidemia before using TAC, 78.6, 35.2, and 51.9% of them were prescribed antihypertensive, antidiabetic, and antilipidemic medications during the follow-up period. Age of ≥40 years was significantly associated with the development of de novo HTN, dyslipidemia, and PTDM (p < 0.05). High TAC trough concentration/daily dose (C(0)/D) ratio was significantly associated with the development of PTDM (p < 0.05). Conclusion: Less than two-fifths of patients achieved target TAC C(0) levels during the first month of PT. Side effects were more common in older patients. These findings warrant efforts to implement targeted multifaceted interventions to improve TAC prescribing and monitoring after KT.