The long-term survival rate of living kidney donors was no different from that of the general population, but kidney donors went through more socioeconomic difficulties, a study showed.
On Wednesday, the National Evidence-based Healthcare Collaborating Agency (NECA) released the study results on changes in the health status of living kidney donors before and after the transplantation and their socioeconomic changes.
More than 2,000 kidney transplants are performed in Korea annually, and about 50 percent of them are donated from living donors. However, local research has been insufficient to deal with short-term and long-term complications of living kidney donors, their health status, psychological and socioeconomic issues.
The researchers matched 2,051 living kidney donors to 2,051 healthy people. The living kidney donors underwent nephrectomy for kidney transplantation from January 1979 to December 2018 at seven national university hospitals, including the Seoul National University Hospital (SNUH). Based on retrospective cohort data, the researchers compared the metabolic risk of the two groups.
The results showed no significant difference in the prevalence of each disease between the donors and the general public.
The prevalence of hyperuricemia (greater than 7 mg/dL in men and greater than 6 mg/dL in women) rose sharply over time in both the donors and the general population. In the donor group, it jumped from 4.6 percent in 1995-2000 to 11.5 percent in 2012-2016. In the general population group, it also rose sharply from 6.5 percent to 16.5 percent during the same period. There was no difference in the increasing trend of the prevalence between the two groups.
Also, the two groups did not show a difference in the prevalence of hypertension (systolic blood pressure at 140 mmHg or higher), which rose from 7.2 percent in 1995-200 to 18.5 percent in 2012-2016 in the donor group, and from 10.5 percent to 24.4 percent in the same period in the general population group.
The prevalence of hypercholesterolemia was similar at 32 percent in the two groups in 1995-2000 but soared to 40 percent in the donor group and 50 percent in the general population in 2012-2016.
To check the donors’ recovery of renal function, the researchers analyzed the chronic kidney disease risk of 1,358 donors from 1982 to 2018.
The study found that kidney survival was longer when the estimated glomerular filtration rate (eGFR) measured early after transplantation was high. Conversely, the donors with a low initial level of eGFR showed a difference in the kidney survival rate according to the amount of change in eGFR measured one month later. Thus, close observation of renal function after kidney donation is necessary, the research team said.
The long-term follow-up of 1,701 living kidney donors and their matching 1,701 general people at the seven national university hospitals showed that the donors’ mortality rate appeared to increase. However, when adjusted with socioeconomic status and residential areas, there was no difference in mortality rates between living kidney donors and the general population.
However, kidney donors had more socioeconomic difficulties than the general population.
The researchers examined the socioeconomic changes of 1,369 donors who received nephrectomy for kidney transplantation at the seven national university hospitals between 2003 and 2016 and the matching 1,369 ordinary people.
The results showed that the donors were more likely to lose a job after kidney donation. In addition, their chance of getting newly employed was significantly lower than that of the general population.
The inequality in employment did not appear two years after the kidney donation, but it could have caused an economic impact in the short term and the long term, the researchers said.
The probability that the donors’ quintile of economic power would rise was also significantly lower, about 0.5 times that of the general population. Conversely, the likelihood of a decline in their economic power quintile, compared to that before the donation, was about 1.4 times higher. This trend was maintained until five years after the donation.
Also, the researchers polled 240 kidney donors at the SNUH and Keimyung University Dongsan Hospital on their socioeconomic changes.
The survey showed that 34.2 percent said they experienced socioeconomic changes. More specifically, 69.5 percent said they were financially worse off due to the cost of surgery for donation. About 55 percent said their subscription or maintenance of health insurance was restricted because of the surgery. Around 43 percent said their careers were interrupted because they had to discontinue study or work for a while.
The donors could not work for 67 days on average. Donors who had a job took only 35 days of unpaid leave, signaling that they did not receive sufficient time to recover.
Regarding pre- and post-donation exams, surgery, and hospitalization, 40.8 percent said the donors had to pay the entire cost, and another 35.4 percent said the recipients did so. Only 24.4 percent of the donors said the cost was covered by private insurance.
Professor Lee Ha-jeong at the Nephrology Department of the SNUH, who led the study, said the researchers confirmed no difference in the metabolic risk and long-term survival rate of living kidney donors compared to the control group in Korea.
However, considering the recent increase in metabolic syndrome, it is not clear whether this trend will be maintained in the future, she said.
“In the long term, it is necessary to establish a systematic and forward-looking national data management system for the safety management of living kidney donors,” she added.