Cystatin C and albuminuria as predictors of long‐term allograft outcomes in kidney transplant recipients

Abstract

Although cystatin C (Cys) and albuminuria (Alb) are predictors of end-stage renal disease in the general population, there are limited data about the performance of these markers alone or combined with respect to the prediction of the kidney transplant outcome. We assessed the ability of one-yr creatinine (Cr), MDRD equation, Cys, Hoek equation, Alb, the logarithm of albuminuria (LogAlb), and two products of these variables for predicting death-censored graft loss (DCGL) in 127 kidney transplant recipients. Mean follow-up time was 5.6 ± 1.7 yr. During this time, 18 patients developed DCGL. The area under the receiver operating characteristic curve for DCGL ranged from 71.1% to 85.4%, with Cys*LogAlb being the best predictor. Cys-based variables and variables combining LogAlb and renal function estimates have better discrimination ability than Cr-based variables alone. After multivariate analysis, quartiles of all one-yr variables (except of Cr and MDRD) were independent predictors for DCGL. Predictors combining Alb and a Cr- or Cys-based estimate of renal function performed better than those markers alone to predict DCGL. Cys-based predictors performed better than Cr-based predictors. Using a double-marker in kidney transplantation, it is possible to identify the highest risk group in which to prioritize specialty care.

Filtration Markers, Cardiovascular Disease, Mortality, and Kidney Outcomes in Stable Kidney Transplant Recipients: The FAVORIT Trial

“…Overall our findings are consistent with results for cystatin C and B2M observed in nontransplant populations (14)(15)(16)(17)(18)(19)(20)(21) and extend the current literature of the strong risk factor associations of these filtration markers with important outcomes into the kidney transplant population. Few studies have evaluated risk associated with cystatin C and B2M in kidney transplant recipients (22)(23)(24)(25). In small studies (sample size from 79 to 129) higher cystatin C levels were associated with graft loss (24,25) and higher serum B2M levels were also associated with eGFR cr decline at 1 and 2 years follow-up (22).…”

“…Few studies have evaluated risk associated with cystatin C and B2M in kidney transplant recipients (22)(23)(24)(25). In small studies (sample size from 79 to 129) higher cystatin C levels were associated with graft loss (24,25) and higher serum B2M levels were also associated with eGFR cr decline at 1 and 2 years follow-up (22). In the largest study to date, Astor and colleagues reported that higher serum B2M levels at discharge were associated with both mortality and graft loss and with associations of greater magnitude when compared to serum creatinine in a cohort of 2190 primary kidney transplant recipients from a single center in the United States (23).…”

“…Few studies have evaluated risk associated with low-molecular-weight serum protein levels in kidney transplant recipients. Prior work suggests that higher B2M is associated with greater eGFR decline 1-2 years posttransplant (22) and that both higher cystatin C and B2M are associated with increased risk of mortality (23) and graft loss (23)(24)(25) in transplant recipients. It is not known, however, whether the potential advantage of the lowmolecular-weight serum protein filtration markers over creatinine for estimating cardiovascular and kidney disease risk associations that have been observed in the nontransplant population are present among transplant patients.…”

Estimating glomerular filtration rate in kidney transplantation: Still searching for the best marker

“…A clinical score constructed from a cross-validated French database of 2169 kidney transplant recipients, combining risk factors of graft loss, including SCr and proteinuria, demonstrated to be highly predictive of long-term kidney graft survival [90] , and other study demonstrated that the combination of low-grade albuminuria and decreased eGFR was related with graft loss and mortality [91] . In a similar way, a recent small-sample singlecenter study [92] founded that predictors combining albuminuria and Cr-or CyC-based eGFR, performed better than those markers alone, to predict death censored graft loss, in kidney transplant recipients. Moreover, the best predictor of graft failure in this work was a product of CyC and the logarithm of albuminuria, and CyC-based predictors performed better than Crbased predictors.…”

Cystatin C: A Primer for Pharmacists

“…CysC predicts graft survival. However, its superiority over SCr has not been consistently established for this purpose [93,94]. For GFR estimation using the reference standard of mGFR, authors have applied equations ( Supplementary Materials Table S1) that were derived from both non-transplant patients (CKD-EPI, MDRD) and transplant recipients (Rule [90] or Le Bricon [95] equation).…”