Cholesterol as an independent predictor of outcome after renal transplantation

Background. The debate on the role of high serum cholesterol levels in cardiovascular disease or chronic vascular rejection in kidney-transplanted patients has not yet been settled. Methods. We studied the influence of serum cholesterol at 1 year after transplantation on the failure risk in all 676 kidney graft recipients who survived with a functioning graft. Other variables included in this analysis were donor/recipient age and gender, original disease, race, number of HLA-A and -B mismatches, previous transplants, postmortal or living-related transplantation, and transplantation year. At 1 year after transplantation, we included: serum cholesterol, serum creatinine, proteinuria, and hypertension. Results. In the Cox proportional hazards analysis, serum cholesterol at 1 year after transplantation turned out to be an important, independent variable influencing all end points (adjusted for all other variables in the model). The influence on graft failure censored for death was log-linear, and there was interaction with serum creatinine at 1 year. The adverse effect of elevated serum cholesterol levels on the graft failure rate decreased with increasing serum creatinine levels. The influence of serum cholesterol on the rate ratio (RR) for patient failure was linear too, and here there was interaction with recipient age. The negative influence of serum cholesterol on the RR for patient failure decreased with increasing recipient age. The risk for over-all graft failure was influenced by increasing serum cholesterol levels, and there was interaction with recipient age. Because recipient age had interaction with donor age and serum creatinine, the influence of all four variables together on the RR was estimated. It is shown that whereas the RR for over-all graft failure in young recipients of a renal transplant increases significantly with higher cholesterol levels, there is very little influence on the RR of elderly recipients. The risk increases proportionally with increasing serum creatinine levels. Conclusion. Serum cholesterol levels have an independent influence on graft, patient, and over-all graft failure.