Factors Affecting Long-Term Renal Graft Survival
Renal transplant patients who are female, younger, or receive a kidney from a living-related donor are significantly more likely to have a functioning renal allograft at 20 years, a study found. Absence of acute rejection also is associated with such long-term allograft survival.
Among 1,174 renal transplant recipients, Irish investigators led by Carol Traynor, MD, of Beaumont Hospital in Dublin, identified 255 (21.7%) who had a functioning graft for 20 years or more. They compared these patients with 747 recipients who died, returned to dialysis or had a second renal transplant in less than 20 years.
After adjusting for multiple potential confounders, men had a significant 23% increased risk of long-term graft loss compared with women, Dr. Traynor's group reported online in the American Journal of Transplantation. “To our knowledge, we are the first to demonstrate superior 20-year graft survival in female recipients,” the authors stated.
Additionally, each one-year increment in recipient age was associated with a significant 1.3% increased risk of graft failure. Recipients of living-related donor kidneys had a 49% decreased risk. Acute rejection was associated with a 25% increased risk.
The researchers observed that 49% of the 20-year group had a history of early acute rejection, so “even in the setting of acute rejection, ultra long-term graft function is possible.”
The study is the first large investigation to characterize the outcome of renal transplantation 20 years later, the researchers noted.
Dr. Traynor and her colleagues also found that five-year graft survival in 20-year survivors (after the 20-year time point) was 74.7%, which is comparable to the proportion found in the general kidney transplant population.
The most common causes of death after 20 years were cardiovascular events (31.6% of deaths) and malignancy (28.9%). The main causes of graft failure in the 20-year group were death with a functioning graft (45.1% of graft failures) and interstitial fibrosis/tubular atrophy (39.4%). In the patients who graft failed prior to 20 years, the most common causes were death with a functioning graft (38.6%) and interstitial fibrosis/tubular atrophy (35.2%).
“As increasing numbers of patients are transplanted, and graft survival improves,” the authors wrote, “physicians will encounter greater numbers of patients with long-term exposure to immunosuppression. Use of a living donor, implementation of appropriate prevention measures and early diagnosis and treatment of long-term complications may further improve long-term transplant survival.”
Dr. Traynor's group noted that their investigation was a single-center study and has the limitations inherent in any such study.