Overall and cardiovascular mortality in Norwegian kidney donors compared to the background population

There are concerns regarding potential long-term risks to the living kidney donor. Cardiovascular mortality has not been evaluated. The aim of this study was to assess overall and cardiovascular mortality in previous kidney donors compared with a general population sample.

All live kidney donors in Norway in the period 1963-2007 were included. Controls matched 3:1 for age, gender and year of birth were provided by Statistics, Norway. Cause of death was retrieved from the death master file. Vital status as of 1 January 2010 was provided for all participants, and cause of death was available until 1 January 2008. Comparative survival analyses were performed by Kaplan-Meier curves and log-rank test. Age-stratified death rates were calculated and compared with a selected group with a health status hypothetically allowing donation.

There were 2269 living kidney donors in the study period. At donation, mean age was 47.6 + 12.6 years, 41.3% were male. Median observation time was 14.3 years. A total of 324 donors died during the study period. Causes of death were similar for donors and controls. By Kaplan-Meier analysis, overall and cardiovascular mortality was lower for previous kidney donors than for matched controls (P < 0.001 and P = 0.004, respectively). Age-stratified death rates were elevated for the oldest group of donors.

Overall and cardiovascular mortality results are partially reassuring. However, the seemingly elevated mortality rate among the oldest donors requires further study.