Blood pressure and the survival of renal allografts from living donors

Levels of BP have been associated with increasing rates of renal allograft failure from cadaveric donors, independent of renal function. The effect of BP, a modifiable risk factor, on the failure rates of renal allografts from living donors is unknown and maybe obscured by the rate of decline of renal function from this source of organs. A nonconcurrent cohort study collecting data from 392 recipients of a renal allograft from a living donor during 1990 to 2001 was performed. Multivariable Cox regression models were fit by means of time-varying terms for systolic BP (SBP), diastolic BP (DBP), mean arterial BP (MAP), pulse pressure, and renal function during the first year after transplantation to study the association of BP and the time to allograft failure. Potential nonlinear relationships were considered by fractional polynomial terms. Recipient gender, preemptive transplantation, and time-varying terms for the natural logarithm of creatinine clearance and acute rejection were retained in the multivariable model. Including separate multivariable models with nonlinear terms for SBP (P = 0.02), for DBP (P = 0.02), or for MAP (P = 0.05) during the first year significantly improved the fit of the respective models and confirmed that there is an association of BP and allograft failure independent of renal function. Pulse pressure had neither a linear nor nonlinear association with allograft failure. In this nonconcurrent study, the level of BP during the first year affected the survival of renal allografts from living donors, independent of renal function. Further investigation is required to confirm the level of BP that is optimal to prevent foreshortened duration of survival.