Very early serum creatinine as a surrogate marker for graft survival beyond 10 years.

BACKGROUND

Available studies of early serum creatinine (SCr) as a surrogate marker for long-term graft loss are multicenter, registry-based or limited to 5- to 7-year survival.

METHODS

This was a single-center observational retrospective study. SCr during the first year post-kidney transplant as an independent variable in determining long-term (>10-year) graft survival in 754 first cadaver kidney transplants was assessed with univariate and multivariate models.

RESULTS

Kaplan-Meier survival estimates showed that recipient female sex, a transplant procedure performed after 1997, donor age under 55 years, immunosuppression including tacrolimus and/or mycophenolate mofetil and absence of acute rejection, were significantly related to better long-term graft survival. SCr at 1, 3, 6 and 12 months stratified into <or=1.5, 1.6-2 and >2 mg/dL groups was also strongly related to long-term graft survival. Multivariate Cox models showed that increased SCr at any point during the first year had a higher relative risk for ultimate graft loss.

CONCLUSIONS

Early graft function is strongly correlated with long-term graft survival (>or=10 years). Mild differences in SCr (1.5 vs. 1.6-2 mg/dL) are associated with highly significant impact on long-term survival, longer than previously described. However, the "hard" predictive value of SCr as an isolated tool is not strong enough. Other early surrogate end points for graft loss are needed.