N-terminal pro-B-type natriuretic peptide and mortality in renal transplant recipients versus the general population

Abstract

Background: Mortality rates are higher in renal transplant recipients (RTR) than in the general population (GP). It is unknown what risk factors account for this difference.

Methods: We prospectively followed a cohort of 606 RTR for 3026 person-years, during which 95 died. A GP cohort of 3234 subjects was followed for 24,940 person-years, during which 130 died.

Results: All investigated risk factors, except ethnicity, body mass index, and total cholesterol, differed significantly between cohorts, with an adverse risk profile in the RTR. The age-adjusted and gender-adjusted hazard ratio for mortality in RTR was 6.2 (95% confidence interval [CI] 4.6-8.3) compared with GP, which was reduced to 2.4 (95% CI 1.6-3.6), 4.3 (95% CI 3.0-6.1), and 5.0 (95% CI 3.5-7.3) after additional adjustment for differences in N-terminal pro-B-type natriuretic peptide (NT-proBNP), creatinine clearance, and need for antihypertensive medication, respectively (all P<0.001), whereas adjustment for variables more related to atherosclerosis, including history of cardiovascular disease, diabetes, and high-density lipoprotein cholesterol, did not affect the difference in mortality between RTR and GP. Associations of NT-proBNP, creatinine clearance, and the use of antihypertensive medication with mortality were significantly steeper in RTR than in GP. Risk for mortality was similar for RTR and GP with low NT-proBNP (<100 pg/mL).

Conclusions: Elevated NT-proBNP, low creatinine clearance, and need for antihypertensive medication are stronger risk factors for mortality in RTR than in GP. The increased mortality seen in the RTR population may well be related to cardiac failure rather than "accelerated atherosclerosis."