iBox Predicts Graft Loss Similarly Across African American and Other Kidney Transplant Recipients

The iBox system predicts long-term death-censored graft loss after kidney transplantation, but its performance in African American recipients has not been fully studied. A multicenter observational study in the Journal of the American Society of Nephrology assessed discrimination, calibration, overall fit and clinical utility in 3,866 North American recipients, including 1,040 (27%) African American recipients.

Discrimination was similar between African American and non-African American recipients: c-indices were 0.80 (95% CI, 0.77–0.83) and 0.83 (95% CI, 0.81–0.85), respectively (p=0.07). Observed-to-expected graft-loss ratios were 1.08 (95% CI, 0.95–1.23) and 0.99 (95% CI, 0.88–1.10), respectively (p=0.28). Multivariable analysis stratified by transplant center found no significant interaction between iBox score and race (p=0.29).

Findings were consistent across Kidney Recipient Specific, CKD-EPI and MDRD equations for estimating glomerular filtration rate, although calibration varied slightly across equations. The authors reported accurate prediction and clinical utility up to seven years after risk evaluation. These findings support iBox use for prognostic assessment in African American recipients; however, this prediction-performance study does not establish that using the system improves clinical outcomes, and nonsignificant subgroup differences do not prove equivalence.