Performance of the iBox Prognostication System in African American Kidney Transplant Recipients
Abstract
Background: The iBox is a validated prognostication system that predicts long-term death-censored graft loss in kidney transplant recipients, but its performance in the specific population of African American recipients has not been fully studied. Methods: We conducted a multicenter study including 3,866 kidney transplant recipients from North America, of whom 1,040 (27%) were African American, to assess the impact of race on the iBox’s performance in predicting graft loss. Discrimination, calibration, overall fit and clinical utility were evaluated in the whole cohort and in African American and non-African American recipients. Results: Performance metrics for the prediction of graft loss were similar in both subgroups in terms of discrimination (c-index 0.80 [95% CI: 0.77-0.83] in African American recipients and 0.83 [95% CI: 0.81-0.85] in non-African American recipients, p=0.07), and observed/expected ratios (1.08 [95% CI: 0.95-1.23] and 0.99 [95% CI: 0.88-1.10], respectively, p=0.28). No significant interaction between iBox score values and race was found in multivariable analysis stratified by transplant center (p=0.29 for the interaction term). Results were consistent between subgroups regardless of the equation used to estimate glomerular filtration rate (Kidney Recipient Specific [KRS], CKD-EPI, or MDRD), with small variations in calibration across equations. Conclusions: The iBox prognostication system showed accurate discrimination, overall fit, and clinical utility up to 7 years post-risk evaluation in African American and non-African American kidney transplant recipients, supporting its robustness in this population.
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Authors: Agathe Truchot, Yannis Lombardi, Marc Raynaud, Olivier Aubert, Gillian Divard, Thibaut Thalamas, Brad C. Astor, Didier A. Mandelbrot, Sandesh Parajuli, Kenneth A. Newell, Christian P. Larsen, Geeta Karadkhele, Babak J. Orandi, John J. Friedewald, Gaurav Gupta, Enver Akalin, Stanley C. Jordan, Arthur J. Matas, Miklos Z. Molnar, Junji Yamauchi, Katalin Fornadi, Andrew Bentall, Mark D. Stegall, Roslyn B. Mannon, Dorry L. Segev, Edmund Huang, William E. Fitzsimmons, Alexandre Loupy
Institutions: Northwestern University, Montefiore Medical Center, Albert Einstein College of Medicine, Emory University, Cedars-Sinai Medical Center, Inserm, Virginia Commonwealth University, University of Minnesota, University of Utah, University of Illinois Chicago, NYU Langone Health, New York University, Université Paris Cité, Sorbonne Université, University of Wisconsin–Madison, Assistance Publique – Hôpitaux de Paris, University of Rochester Medicine, Mayo Clinic in Florida, University of Nebraska Medical Center, Hôpital Tenon, Hôpital Saint-Louis, Paris Cardiovascular Research Center, Saint Louis University Hospital