Mortality in living kidney donors: An australian and new zealand cohort study using data linkage.

Abstract

Aim: To compare mortality in living kidney donors with the general population in Australia and New Zealand. Background(s): Living kidney donors are a highly selected group in excellent health, but long-term outcome studies are sparse. We hypothesised donors would have lower death rates and improved survival versus the general population. Method(s): We included all living kidney donors in Australia, 1996-2013 and New Zealand, 2003-2012 from the Living Donor Registry. We ascertained primary cause of death from data linkage with national death registries and donor-related data from the Living Donor Registry. Standardized mortality ratios (SMRs) were estimated using indirect standardization, matching on age, gender, calendar year and country. Relative survival was estimated using Paul Dickman approach with Ederer II estimates. Result(s): Among 3,315 living kidney donors, there were 35 deaths over 22,424person-years with median follow-up 5years [Interquartile range, IQR:2.8-7.3]. Median time from donation to death was 5.4years [IQR:1.6-7.2]. There were 5 deaths in the first year; 3 from immediate complications of donation, and one each from traffic accident and accidental fall. The leading cause of death was cancer (n=17), followed by cardiovascular (n=6). The median age at donation was higher in donors who died; 61years [IQR:57-65] compared to donors still alive, 49years [IQR:41-57]. The crude mortality rate during the first year from donation was 151 (95% CI:63-363)/100,000pys. The overall SMR was 0.34 (95%CI:0.24-0.47), where living kidney donors had 66% fewer deaths than expected in the general population. The relative survival remained at or above 1.00 up to 10 years from donation. Conclusion(s): All-cause mortality in living kidney donors was substantially lower than expected in the general population. These data are reassuring and helpful for clinical decision-making.