The role of death in kidney graft failure.

Using the UNOS Scientific Renal Registry data on 41,407 first-time recipients of cadaveric kidneys surviving at least 3 months who underwent transplantation between January 1991-October 1998, we identified the following mortality rates and relationships: 1. The average mortality risk began near 25 deaths/year/1000 transplants in young children, declined to about 10 deaths/year/1000 transplants at adulthood and then steadily increased to near 80 deaths/year/1000 transplants in patients reaching age 75. Diabetic patients exhibited the highest death rates starting near 20 deaths/year/1000 transplants at age 30 and climbing to 92 deaths/year/1000 transplants at age 75. Apart from children and older patients, cadaveric kidney transplant death rates were approximately 5 times greater than in the general US population. 2. The risk of death for adult kidney transplant patients increased exponentially with age and was reduced by a factor of about half compared with rates reported in 1988. 3. Secondary analyses (using 6,492 cadaveric-kidney regrafted patients and 15,169 first-time recipients of kidneys from living donors during 1991-98) showed that adult death rates comparing first and repeat transplants were essentially the same and, generally, living-donor kidney recipients exhibited lower risks of death compared with cadaver-donor recipients but, again, substantially higher risks compared with the general population. 4. Patient mortality for adults was described by the sum of 2 components of risk: age-dependent risk and transplant-dependent risk. Mortality risks more or less increased linearly (on the log scale) from baselines of 10 deaths/year/1000 transplants as a function of patient age and 0.06 deaths as a function of posttransplant time. Typically, the age-dependent risk increased about 10 times over baseline in 40 years whereas the transplant-dependent risk increased 10 fold in 2 1/2 years posttransplant. 5. From the patient's point-of-view, the initial high-risk period of mortality following kidney transplantation has vanished and the remaining deaths in this period can be counted as non-failures, making graft survival rates higher.