Pretransplant NT-proBNP, Dialysis Vintage, and Posttransplant Mortality in Kidney Transplant Recipients

Background. End-stage kidney disease and dialysis vintage are characterized by accelerated atherosclerosis, volume overload, and progressive left ventricular hypertrophy, leading to elevated N-terminal probrain natriuretic peptide (NT-proBNP) levels. Pretransplant dialysis vintage is associated with excess mortality after transplantation. We want to study whether pretransplant NT-proBNP is associated with posttransplantation mortality and if it explains the association of dialysis vintage with posttransplantation mortality in kidney transplant recipients (KTR). Methods. We measured plasma NT-proBNP on arrival at the hospital before kidney transplantation in 658 KTR between January 1995 and December 2005 in our center. Multivariable Cox regression analyses, adjusted for potential confounders, were used to prospectively study the associations of dialysis vintage and NT-proBNP with all-cause mortality. Results. During median 12.7 (7.8-15.6) years of follow-up after transplantation, 248 (37.7%) KTR died. Dialysis vintage was associated with an increased risk of posttransplant mortality in the fully adjusted model (hazard ratio [HR], 1.22; 95% confidence interval [CI], 1.03-1.43;P= 0.02), independent of potential confounders. The association weakened materially and lost significance after further adjustment for NT-proBNP (HR, 1.14; 0.96-1.34;P= 0.14). NT-proBNP was independently associated with all-cause mortality in the fully adjusted model (HR, 1.34; 1.16-1.55;P< 0.001). The association remained independent of adjustment for dialysis vintage (HR, 1.31; 1.13-1.52;P< 0.001). Conclusions. Our study shows that longer dialysis vintage is associated with a higher mortality risk in KTR, and this association might be explained for a considerable part by variation in pretransplant NT-proBNP at the time of transplantation.