Abstract
Background and Purpose:
Healthy older living donors (>50 years) are helping meet increasing demands for kidney transplantation. Live donor grafts perform better than cadaveric donor grafts; however, concern surrounds the expected nephron loss of the donors as well as the relative safety to the donor. We examined the effect age had on living laparoscopic donor and recipient outcomes at a single institution.
Patients and Methods:
We retrospectively reviewed records of 101 patients who underwent laparoscopic donor nephrectomy (LDN) from October 2001 to December 2005. Twenty-nine (29%) who were aged 50 years or older, denoted as the “older” group, were compared with the remaining 72 (71%) donors who were younger than 50 years and served as controls. Perioperative and follow-up data were analyzed for both groups.
Results:
The mean age at the time of donation was 36.1 and 54.3 years for control and older donors, respectively (P < 0.001). Baseline mean creatinine level was 0.82 mg/dL for controls and 0.84 mg/dL for older donors (P = 0.78). Complications in controls and the older group were 18% and 17%, respectively. One-year transplant survival was 100% for the controls and 96% for the older group. Average creatinine level at longer follow-up of 19 months for controls and 23 months for the older group (P = 0.34) was 1.22 mg/dL and 1.16 mg/dL, respectively (P = 0.535).
Conclusion:
LDN in donors older than 50 years of age appears safe and demonstrates similar outcomes compared with the control cohort of patients younger than 50 years. Age between 50 and 65 years should not exclude a potential donor who otherwise satisfies donor nephrectomy criteria.
Introduction
A great deal of controversy exists regarding the use of renal allografts from live older donors because of age-related structural and functional changes within the kidneys. These changes, including nephrosclerosis, atherosclerosis, and decrease in glomerular filtration rate, may be compounded by adverse perioperative events, including warm ischemia time, allograft rejection, and nephrotoxic immunosuppressant medications. Few publications to date have focused on the safety to the older donor or have focused specifically on the safety of older donors in the laparoscopic setting. 4 –6 We examined the effect that increased donor age (>50 years) had on remaining donor kidney function and recipient allograft function in our transplant population.
Patients and Methods
A retrospective review of the renal transplant program at the University of Iowa Hospitals and Clinics from October 2001 to December 2005 revealed 101 living donors. Twenty-nine (29%) were ≥ 50 years of age (range 50–65 years) and 72 (71%) were under 50 years (range 19–49 years). For the purpose of our study, patients ≥ 50 years were designated the “older” group, while patients <50 served as the control group. This age parameter was determined based on the institutional policy at the time of the transplantations. Preoperative and postoperative data from the older donors and their recipients were compared with the controls. Institutional Review Board approval was obtained.
Both donors and recipients underwent extensive evaluation in concordance with the policies that were established by the University Transplant Committee. Preoperative donor evaluation included physical examination, hematologic and biologic screening, chest radiography, electrocardiography, urine microscopy and culture, CT or magnetic resonance angiography of the abdomen and pelvis, as well as tissue typing and matching. Cardiac stress testing and echocardiography were performed when indicated. Donor selection was based on absence of systemic disease and detectable malignancies in combination with the presence of structurally and functionally normal kidneys. All donors in this series underwent laparoscopic (standard or hand-assisted) donor nephrectomy.
All recipients received a combination of immunosuppression, including a calcineurin inhibitor (tacrolimus or cyclosporine), an antimetabolite (azathioprine or mycophenylate mofetil), and prednisone. Recipient immunosuppression regimens were created on an individual basis, but the same regimens were applied to both older and control groups. Post-transplant donor kidney function and morbidity were evaluated as well as recipient allograft function and survival. Kidney function was assessed using serum creatinine levels. Donors were followed for 1 month by our institution and then encouraged to have biannual follow-up examinations by their local physician to assess kidney function, blood chemistry, and blood pressure. We then followed up with the donors through their local physicians for an update on serum creatinine levels and blood pressure for determination of long-term effect.
Recipients were followed initially on a monthly basis and then as deemed necessary by their transplant physician. The average follow-up for the recipients was 26.3 months (range 4–54 mos). Follow-up included physical examination, blood pressure measurement, urinalysis, and determination of serum creatinine level. Rejection episodes were managed with methylprednisolone, dexamethasone, or antithymocyte globulin according to severity of rejection. Delayed graft function was considered a recipient serum creatinine level greater than 3 mg/dL 1 week after transplantation.
Statistical analyses were performed using PRISM Version 4.0 (GraphPad Software, San Diego, CA). The Student t test was used to compare the two groups, and results were considered statistically significant at P < 0.05.
Results
Donors
The average age of the donors was 36.1 and 54.3 years for the control and the older group, respectively (P < 0.001). Women made up the majority of all donors: 62% of the control group and 77% of the older group. The number of surgical and perioperative complications in donors was similar between the two groups, with 18% in the controls and 17% in the older group. There was no difference in complications between groups, which included drainage of wound abscess, incisional hernia repair, and postoperative ileus. Rhabdomyolysis of the leg developed in one morbidly obese patient in the control group from intraoperative positioning and a prolonged procedure; it resolved before discharge. A pulmonary embolism developed in another patient from the control group; the embolism necessitated treatment with anticoagulation. Further donor characteristics and outcomes are found in Table 1.
ASA = American Society of Anesthesiologists.
At short-term follow-up (30 days after organ donation), the serum creatinine level increased an average of 0.4 mg/dL in both groups for a final serum creatinine level of 1.21 mg/dL for the control and 1.24 mg/dL for the older group (P = 0.8). Long-term follow-up was obtained for 20 patients in each group (total of 40) for whom information was made available by their local physicians. Average date from initial follow-up was 19.3 months (range 6–46 mos) and 22.9 months (range 7–45 mos) for control and older donors, respectively (P = 0.44).
Average serum creatinine level at long-term follow up was 1.20 mg/dL and 1.15 mg/dL for control and older donors, respectively (P = 0.57). The change in serum creatinine level from the initial to the long-term follow-up visit was an increase of 0.37 mg/dL and 0.35 mg/dL for control and older donors, respectively (P = 0.65). Only one patient in the older group had evidence of hypertension at long-term follow-up of 150/82 mm Hg, which was moderately different from preoperative and postoperative blood pressure measurements of 126/77 mm Hg and 114/73 mm Hg. Twenty-eight of the patients (17 in control, 11 in the older group) had long-term urinalysis performed; all results were negative.
Recipients
When comparing recipients who received a kidney from older donors with those who received a kidney from a younger donor, there was no difference in follow-up time, serum creatinine level on postoperative day 3, or serum creatinine level at long-term follow-up (Table 2). There were no mortalities in either group. One graft failed in the older group because of acute rejection. That patient subsequently underwent a cadaveric renal transplantation with good results. No grafts failed in the control group. Table 2 contains further recipient characteristics and follow-up data.
ASA = American Society of Anesthesiologists; HLA = human leukocyte antigen; POD = postoperative day.
Discussion
As humans age, kidney mass decreases and overall renal function begins to decline as early as the third decade of life. The clinical significance of the decreased function is likely minimal unless the patient experiences acute illness or is forced to rely on a solitary kidney, as is the case of contralateral renal disease. 7 The need of both the recipient and donor to rely solely on a single aged kidney, in combination with recent studies that have demonstrated transplantation with greater nephron mass results in decreased incidence of both acute and chronic rejection, 8 have contributed to the concerns about older donors. In addition, studies have demonstrated that advanced cadaveric donor age is a risk factor for delayed graft function, rejection and reduced allograft survival. 9
In opposition to these findings, however, are recent studies that have found no difference in graft survival or function in recipients from elderly living donors compared with younger donors. 10 –12 Johnson and associates 13 found that older donors have increased serum creatinine levels at 1 year follow-up compared with younger donors; however, this study did not specifically compare laparoscopic donor groups and had a shorter follow-up time. Also in contrast to the findings of Johnson and colleagues 13 were those of El-Agroudy and coworkers 4 who found that renal function in older donors is relatively stable over time.
Our data also support that older patients (>50 years) who undergo laparoscopic donation have similar transplantation success rates as younger donors and reasonable donor age has little effect on remaining donor kidney function. We also found no difference in recipient allograft function. Our data is in line with a study published by Kumar and associates 10 that reported no added morbidity or increased risk for older donors, because there was no difference in serum creatinine level up to 2 years after donation.
Limitations of our study include the fact that it is a single institution cohort study, its retrospective nature, the limited follow-up of donors, and use of the serum creatinine level as a surrogate of renal function. We used the serum creatinine level to measure renal function for comparison between control and older groups. Because our institution is a tertiary referral center, many patients travel a great distance to undergo donor nephrectomy. Because of this long distance and our high clinical volume, we encourage donors to follow up with their local physicians if they do not have problems at their 1-month follow-up appointment.
Conclusion
Review of our data clearly indicates that donors older than 50 years of age who are deemed healthy enough to donate a kidney via standard preoperative testing have similar success rates compared with a younger cohort of patients. Perioperative donor complications are similar and, more importantly, postsurgical renal function of both the donor and recipient are similar. These results should alleviate some of the concerns regarding the effect that age has on remaining donor renal function. Age up to 65 years should not exclude a potential donor for LDN who otherwise satisfies donor nephrectomy criteria.
Footnotes
Disclosure Statement
No competing financial interests exist.