Long-term survival similar for kidney donors, general population

The long-term survival rate of living kidney donors was no different from that of the general population, but kidney donors had more socio-economic difficulties, one study showed.

On Wednesday, the National Evidence-based Healthcare Collaborating Agency (NECA) published the study results on changes in the health status of living kidney donors before and after transplantation and their socio-economic changes.

More than 2,000 kidney transplants are performed in Korea each year, and about 50 percent of these are from living donors. However, local research was insufficient to address the short- and long-term complications of living kidney donors, their health status, and psychological and socio-economic issues.

The researchers assigned 2,051 living kidney donors to 2,051 healthy people. The living kidney donors underwent nephrectomy for a kidney transplant from January 1979 to December 2018 at seven national university hospitals, including 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 donors and the general public.

The prevalence of hyperuricemia (greater than 7 mg / dl in men and more than 6 mg / dl in women) increased sharply over time in both donors and the general population. In the donor group, it rose 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 over the same period. There was no difference in the increasing trend in prevalence between the two groups.

Also, the two groups showed no difference in the prevalence of hypertension (systolic blood pressure at 140 mmHg or higher), which went from 7.2 percent in 1995-200 to 18.5 percent in 2012-2016 in the donor group and from 10.5 percent rose to 24.4 percent over the same period in the general population.

The prevalence of hypercholesterolemia was similar in the two groups at 32 percent in 1995-2000, but increased to 40 percent in the donor group and 50 percent in the general population between 2012 and 2016.

To verify the restoration of the donors’ kidney 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 the transplant, was high. Conversely, the donors with a low initial eGFR level showed a difference in kidney survival according to the change in eGFR measured one month later. Therefore, close monitoring of kidney function is needed after a kidney donation, the research team said.

Long-term follow-up examinations of 1,701 living kidney donors and their corresponding 1,701 general patients at the seven national university hospitals showed that donor mortality rates appeared to be increasing. However, after adjusting for socioeconomic status and residential areas, there was no difference in the mortality rate between living kidney donors and the general population.

However, kidney donors have faced more socio-economic difficulties than the general population.

The researchers examined the socio-economic changes of 1,369 donors who received nephrectomy for a kidney transplant between 2003 and 2016 at the seven national university hospitals, and the corresponding 1,369 ordinary people.

The results showed that donors were more likely to lose their jobs after kidney donation. In addition, their chances of being hired were significantly lower than that of the general population.

Employment inequality did not occur two years after kidney donation, but it could have had economic effects in the short and long term, the researchers said.

The probability that the quintile of the donors’ economic power would rise was also significantly lower, around 0.5 times the total population. Conversely, the likelihood of a decline in their economic power quintile was around 1.4 times higher than before the donation. This trend was maintained until five years after the donation.

The researchers also asked 240 kidney donors at the SNUH and the Dongsan Hospital of Keimyung University about their socio-economic changes.

The survey found that 34.2 percent said they had experienced socio-economic changes. More precisely, 69.5 percent said they were financially worse off because of the cost of a donation operation. About 55 percent said their subscription or maintaining health insurance was restricted because of the surgery. Around 43 percent said that their career had been interrupted because they had to temporarily break off their studies or work.

The donors could not work for an average of 67 days. Job donors only took 35 days of unpaid leave, suggesting they did not have enough time to recover.

For pre-donation and post-donation examinations, surgeries, and hospital stays, 40.8 percent said the donors paid all of the costs, and another 35.4 percent said the recipients did. Only 24.4 percent of the donors said that the costs were covered by private insurance.

Professor Lee Ha-jeong of the SNUH’s Nephrology Division, who led the study, said the researchers had confirmed no difference in metabolic risk and long-term survival rate of living kidney donors compared to controls in Korea.

However, given the recent surge in metabolic syndrome, it is not clear whether this trend will continue in the future, she said.

“In the long term, it is necessary to establish a systematic and future-oriented national data management system for the safety management of living kidney donors,” she added.

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