By Leslie Spry, MD, FACP FASN
In 2007, there were 6,041 kidney transplants performed with living donors and this number has remained stable over the last seven years. Indeed, since 1988, a total of 89,488 living donor kidney transplants have been performed. This means that there are many living donors and recipients that have been involved in a very special act of altruism. Altruism is defined as the “unselfish concern for the welfare of others”. As a transplant physician, I consider it one of my duties to inquire about the health of the donor for each and every transplant patient that I see in my office. I want transplant recipients to understand this wonderful act of altruism. This article discusses what is known about the physical and psychological aspects of donating a kidney to another individual. My goal is to bring the donor and the recipient of a kidney transplant into an interchange whereby both can feel comfortable discussing the act that has changed both of their lives forever.
On average, any person who is accepted as a kidney transplant donor is healthier than the average person in the population. Many studies have looked at the physical and psychological characteristics of kidney transplant donors to find that, prior to donation, these individuals are in excellent health. Studies that compare the outcomes of patients who donate kidneys with the “expected outcome in the general population” should recognize that kidney donors are among the healthiest individuals in the population.
The risks of donor nephrectomy (the surgery to donate a kidney) are very small. Most studies report death rates for donor nephrectomy in the range of 1 or 2 per 10,000 donor surgeries. About 1 or 2 per 100 patients may experience a post-operative wound infection or complication and about 50% of these may require re-operation for a complication. Hence, the immediate risk from donating a kidney is very small, but all donors and all transplant recipients need to understand the risks that have been taken by the donor. This truly does qualify as an act of altruism. This unselfish act should benefit both individuals. The benefits to the recipient are obvious. The risks and benefits to the donor, over the long term, need to be explored and appreciated.
The removal of one kidney results in the loss of 50% of the kidney mass for that donor. Hence, one would expect that after donation the measured kidney function would be decreased by 50%. We measure kidney function by tests that measure glomerular filtration rate (GFR). GFR is the rate at which the kidney filters the waste products or toxins. Removal of one kidney for donation means the other kidney must do the work of two and when we use tests to measure the remaining kidney function, we find that that GFR test, with one kidney, averages about 70 to 75% at one year post donation. Hence, the remaining kidney increases its function by 20 to 25% over the course of one year. This means that the remaining kidney is working harder, but this does not seem to cause problems for most donors.
Aging alone results in some loss of kidney function. Age-related loss of kidney function is usually estimated at about 1% per year after age 40. In long term studies of kidney function after donation, it is rare for donors to lose their entire remaining kidney function. In a report from the Organ Procurement and Transplantation Network in 2002, only 56 donors out of over 50,000 donations since 1987 resulted in kidney failure that required a transplant. Current policy in the United States is that donors who lose their entire remaining kidney function and require dialysis, go to the top of the list for kidney transplantation.
In studies of kidney function after donation, some studies have suggested an increase in the protein loss from the kidney into the urine after donation. As mentioned earlier, the remaining kidney increases its work as a result of loss of the other kidney. This increase in work is described as hyperfiltration and can result in an increase in the protein losses by the kidney. The test for hyperfiltration and protein in the urine is known as a microalbuminuria test and should be monitored in the donor to see if this becomes a complication. If microalbuminuria is detected, we do have medical treatment for this complication.
The other complication that has been mentioned in long term studies of donation is high blood pressure and heart disease. This has been an inconsistent finding. Recall that donors are generally healthier than the average population at the time of donation and, as such, would be expected to have a lower risk of heart disease and high blood pressure. Indeed, it has been shown that living donors, on average, live longer than the general population. Despite this, some studies have shown a higher blood pressure after donation than age matched controls and this could translate into complications of high blood pressure such as stroke and heart disease. Another aspect of this complication is that family members of patients with kidney disease are known to be at increased risk of high blood pressure, heart disease and kidney disease, just by virtue of the fact that they are genetically related to the individual with kidney disease. So the development of high blood pressure and heart disease may not directly result from the donation, but rather from the risk factor of family history and genetics. I recommend that all donors have their blood pressure checked regularly and treatment is indicated for blood pressures above normal.
The psychological aspects of kidney donation have not been as well studied, but are usually cited as the benefit to the donor. In the case of living related donor and living emotionally related donors (spouses), the benefit is in seeing a loved one restored to good health after seeing them struggle with dialysis. Studies have indicated that more than 80% of living related donors look back on their act of donation and have very positive feelings about that act. Most living donors undergo psychological assessment prior to donation to make sure they are not being pressured into an operation they do not want and, if this is found, they are commonly offered a medical excuse as to why they are not a donor in order to escape the prejudice that might be associated with a refusal to donate. In some psychological reports, 10% of donors feel some pressure to donate and similar numbers have been pressured not to donate by family and spouse. Hence, it is important that the reasons behind the offer to donate be explored completely prior to allowing a donation to proceed. Psychological testing must also determine that the donor is capable of participating fully in the informed consent process for the donor operation. This is especially true in donors who are not genetically or emotionally related. These so-called “Samaritan donors” have commonly been subjected to very intense psychological screening because the emotional benefit to these donors is not intuitively obvious. In psychological evaluation of these Samaritan donors, it has been shown that a number of them have underlying psychological problems that result in their rejection as a donor. Intolerable motivations for Samaritan donors have been listed as: (1) seeking individual or societal approval, (2) compensation of any kind, (3) atonement for past deeds, or (4) redemption for past deeds. Most decisions to accept Samaritan donors have been very individualized on a case-by-case decision as judged by the transplant team. There have not been any reports of long term follow up of Samaritan donors, either physically or emotionally. Such studies need to be done.
For long term follow up of living donors, the most important factor has been the closeness of the relationship prior to donation. Psychological studies of potential donors have generally shown the same thing as physical characteristics. Transplant donors tend to rate their quality-of-life as better than the general population prior to transplant donation, and after donation tends to be a bit lower, but still better than the general population. These studies show that 80 to 97 would have made the decision to donate in retrospect and less than 1% regretted the decision. Psychological complications reported in studies included 3 to 10% incidence of depression, 10% reported “family conflicts”, 7% with anxiety disorders, 16% concerned about negative financial consequences of donation, and 3 to 15% concerned about a negative impact on their health. In general, the more distant the relative who was the donor, the more likely there was to be a report of emotional complications or problems. In a United States study of live kidney donors from 1998 (prior to widespread use of laparoscopic kidney donation techniques) 29% reported concerns about the time they missed work, 26% were concerned about a return to their usual level of physical activity, 10% were concerned about their ability to care for their children and 2% about their job security. In this study that used a follow up survey of 61 donors, 29% had no socioeconomic concerns at all. Most studies report a closer relationship between the donor and the recipient after transplant than prior to transplant. Most welcomed this aspect of the donation experience.
In conclusion, we need more long term follow up studies of living donors in order to make sure that the benefits do occur as reported. We have some long term studies of the physical health of living kidney donors, but we need more long term follow up of the psychological and emotional aspects of kidney donation. Kidney transplant recipients need to inquire regularly about their donors and transplant physicians should do the same.
Dr. Leslie Spry is a transplant nephrologist at the Lincoln Nephrology and Hypertension Dialysis Center in Nebraska.