The Associations Between Body Mass Index and Kidney Transplant Outcomes Are Mediated by Weight-Adjusted Immunosuppression Dosing.

K. Flabouris,^1,2 S. Chadban,^1,3,4 M. Ladhani,^1,3,5 M. Cervelli,⁶ P. Clayton.^1,2,6

¹Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry, Adelaide, Australia
²School of Medicine, University of Adelaide, Adelaide, Australia
³Sydney Medical School, University of Sydney, Sydney, Australia
⁴Department of Renal Medicine, Royal Prince Alfred Hospital, Sydney, Australia
⁵Department of Renal Medicine, Lyell McEwin Hospital, Adelaide, Australia
⁶Central Northern Adelaide Renal and Transplantation Service, Royal Adelaide Hospital, Adelaide, Australia

Meeting: 2017 American Transplant Congress

Abstract number: 356

Keywords: Dosage, Immunosuppression, Kidney transplantation, Obesity

Session Information

Session Name: Concurrent Session: Kidney: Cardiovascular and Metabolic

Session Type: Concurrent Session

Date: Monday, May 1, 2017

Session Time: 4:30pm-6:00pm

Presentation Time: 5:18pm-5:30pm

Location: E451b

Purpose: High body mass index (BMI) is associated with acute rejection after kidney transplantation. We hypothesised that weight-adjusted immunosuppression dosing is a contributing factor. We therefore examined associations between BMI and acute rejection and infectious death, and whether immunosuppression dosing mediated these associations.

Methods: Using data from the Australia and New Zealand Dialysis and Transplant (ANZDATA) registry, we included all adult kidney-only transplant recipients over 2000-2014 (n=10,761). We used Cox models to examine associations between baseline BMI and: (1) time to acute rejection; (2) time to infectious death. We then modelled BMI and immunosuppression dosing as time-varying covariates in extended Cox models, including only patients treated with prednisolone, mycophenolate and a calcineurin inhibitor. Immunosuppression dosing was determined by grouping patients into quartiles of prednisolone dose/kg, mycophenolate dose/kg, and tacrolimus vs cyclosporin (binary covariate).

Results: Higher baseline BMI was associated with increased risk of acute rejection (adjusted hazard ratio (aHR)=1.14 per 5kg/m² (95%CI 1.09-1.19), p<0.001). Baseline BMI was not significantly associated with infectious death. In time-varying analyses (n=7,919), higher BMI remained associated with rejection (aHR=1.16 (1.10-1.22), p<0.0001) but this association was attenuated after adjusting for immunosuppression dosing (aHR=1.08 (1.01-1.15), p=0.03). Higher time-varying BMI was associated with fewer infectious deaths (aHR=0.75 (0.65-0.86), p=0.0001) but not after adjusting for immunosuppression.

Conclusion: Higher BMI was associated with more acute rejection and fewer infectious deaths after kidney transplantation. Adjusting for weight-adjusted immunosuppression dosing attenuated these associations, suggesting that under-dosing of obese patients and over-dosing of underweight patients may mediate these associations. Dosing practices may require further examination in patients with abnormal BMI.

CITATION INFORMATION: Flabouris K, Chadban S, Ladhani M, Cervelli M, Clayton P. The Associations Between Body Mass Index and Kidney Transplant Outcomes Are Mediated by Weight-Adjusted Immunosuppression Dosing. Am J Transplant. 2017;17 (suppl 3).

To cite this abstract in AMA style:

Flabouris K, Chadban S, Ladhani M, Cervelli M, Clayton P. The Associations Between Body Mass Index and Kidney Transplant Outcomes Are Mediated by Weight-Adjusted Immunosuppression Dosing. [abstract]. Am J Transplant. 2017; 17 (suppl 3). https://atcmeetingabstracts.com/abstract/the-associations-between-body-mass-index-and-kidney-transplant-outcomes-are-mediated-by-weight-adjusted-immunosuppression-dosing/. Accessed May 28, 2025.

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