Race, Calcineurin Inhibitor Exposure, and Renal Function After Solid Organ Transplantation

Area of Science:

• Nephrology
• Transplantation Medicine
• Pharmacology

Background:

• Calcineurin inhibitor (CNI)-induced nephrotoxicity is a common complication in organ transplantation.
• African Americans have a higher risk of renal failure, raising concerns about differential CNI effects.
• This study examines race as a potential modifier of CNI nephrotoxicity in nonrenal solid organ transplant recipients.

Purpose of the Study:

• To investigate whether race modifies the association between calcineurin inhibitor exposure and kidney function post-transplantation.
• To determine if African-American patients experience greater nephrotoxicity from CNIs compared to other racial groups.

Main Methods:

• Retrospective cohort study of 1609 patients undergoing nonrenal solid organ transplantation (2000-2012).
• Data collected from administrative databases including demographics, comorbidities, and serial drug levels (tacrolimus, cyclosporine) and serum creatinine.
• Exposure assessed by total drug exposure (area under the concentration-time curve); outcome measured by cumulative change in estimated glomerular filtration rate (GFR).

Main Results:

• A decline in estimated GFR was observed with increasing exposure to both tacrolimus and cyclosporine.
• Specifically, tacrolimus exposure correlated with a -1.3 mL/min/1.73 m(2) GFR decline per 5 ng/mL·year increase.
• Cyclosporine exposure correlated with a -1.1 mL/min/1.73 m(2) GFR decline per 50 ng/mL·year increase.
• Crucially, the effect of total CNI exposure on GFR changes did not significantly differ between racial groups (P interaction > 0.5 for both drugs).

Conclusions:

• Total calcineurin inhibitor exposure is linked to diminished kidney function in nonrenal solid organ transplant recipients.
• Contrary to initial concerns, African-American patients do not exhibit increased vulnerability to chronic CNI-induced nephrotoxicity compared to white patients.