Long-term Mortality Risks Among Living Kidney Donors in Korea

Abstract

Rationale & objective: Living kidney donors may have a higher risk for death and kidney failure. This study aimed to investigate the long-term mortality experience of living kidney donors compared with members of the general public in Korea who underwent voluntary health examinations.

Study design: Cohort study.

Setting & participants: We first calculated standardized mortality ratios for 1,292 Korean living kidney donors who underwent donor nephrectomy between 1982 and 2016 and 72,286 individuals who underwent voluntary health examinations between 1995 and 2016. Next we compared survival between the 1,292 living kidney donors and a subgroup of the health examination population (n=33,805) who had no evident contraindications to living kidney donation at the time of their examinations. Last, a matched comparator group was created from the health examination population without apparent contraindication to donation by matching 4,387 of them to donors (n=1,237) on age, sex, body mass index, estimated glomerular filtration rate, urine dipstick albumin excretion, previously diagnosed hypertension and diabetes, and era.

Exposures: Donor nephrectomy.

Outcomes: All-cause mortality and other clinical outcomes after kidney donation.

Analytical approach: First, standardized mortality ratios were calculated separately for living kidney donors and the health examination population standardized to the general population. Second, we used Cox regression analysis to compare mortality between living kidney donors versus the subgroup of the health examination population without evident donation contraindications. Third, we used Cox regression analysis to compare mortality between living kidney donors and matched comparators from the health examination population without apparent contraindication to donation.

Results: The living kidney donors and health examination population had excellent survival rates compared with the general population. 52 (4.0%) of 1,292 kidney donors died during a mean follow-up of 12.3±8.1 years and 1,072 (3.2%) of 33,805 in the health examiner subgroup without donation contraindications died during a mean follow-up of 11.4±6.1 years. Donor nephrectomy did not elevate the hazard for mortality after multivariable adjustment in kidney donors and the 33,805 comparators (adjusted HR, 1.01; 95% CI, 0.71-1.44; P=0.9). Moreover, living donors showed a similar mortality rate compared with the group of matched healthy comparators.

Limitations: Donors from a single transplantation center. Residual confounding owing to the observational study design.

Conclusions: Kidney donors experienced long-term rates of death comparable to nondonor comparators with similar health status.

Keywords: All-cause mortality; Asian ethnicity; ESRD risk; donor safety; end-stage renal disease (ESRD); estimated glomerular filtration rate (eGFR); health screening; kidney donor outcomes; living kidney donor; long-term risk; renal function; safety of donation.