Proteinuria after renal transplantation affects not only graft survival but also patient survival.
BACKGROUND
Proteinuria is associated with an increased risk of renal failure. Moreover, proteinuria is associated with an increased death risk in patients with diabetes mellitus or hypertension and even in the general population.


METHODS
One year after renal transplantation, we studied the influence of the presence of proteinuria on the risk of either graft failure or death in all 722 recipients of a kidney graft in our center who survived at least 1 year with a functioning graft. Proteinuria was analyzed both as a categorical variable (presence versus absence) and as a continuous variable (quantification of 24 hr urine). Other variables included in this analysis were: donor/recipient age and gender, original disease, race, number of HLA-A and HLA-B mismatches, previous transplants, postmortal or living related transplantation, and transplantation year. At 1 year after transplantation, we included: proteinuria, serum cholesterol, serum creatinine, blood pressure, and the use of antihypertensive medication.


RESULTS
In the Cox proportional hazards analysis, proteinuria at 1 year after transplantation (both as a categorical and continuous variable) was an important and independent variable influencing all endpoints. The influence of proteinuria as a categorical variable on graft failure censored for death showed no interaction with any of the other variables. There was an adverse effect of the presence of proteinuria on the graft failure rate (RR=2.03). The influence of proteinuria as a continuous variable showed interaction with original disease. The presence of glomerulonephritis, hypertension, and systemic diseases as the original disease significantly increased the risk of graft failure with an increasing amount of proteinuria at 1 year. The influence of proteinuria as a categorical variable on the rate ratio for patient failure was significant, and there was no interaction with any of the other significant variables (RR=1.98). The death risk was almost twice as high for patients with proteinuria at 1 year compared with patients without proteinuria. The influence of proteinuria as a continuous variable was also significant and also without interaction with other variables. The death risk increased with increasing amounts of proteinuria at 1 year. Both the risks for cardiovascular and for noncardiovascular death were increased.


CONCLUSIONS
Proteinuria after renal transplantation increases both the risk for graft failure and the risk for death.
Roodnat
J I
JI
Department of Internal Medicine, University Hospital Rotterdam-Dijkzigt, Dr. Molewaterplein 40, 3015GD Rotterdam, The Netherlands. Roodnat@Inw1.AZR.NL
Mulder
P G
PG
Rischen-Vos
J
J
van Riemsdijk
I C
IC
van Gelder
T
T
Zietse
R
R
IJzermans
J N
JN
Weimar
W
W
D000328:Adult; D006085:Graft Survival; D006801:Humans; D016030:Kidney Transplantation / Q000009:adverse effects* / Q000401:mortality*; D008875:Middle Aged; D016016:Proportional Hazards Models; D011507:Proteinuria / Q000209:etiology*; D012307:Risk Factors; D016019:Survival Analysis