CLINICAL EPIDEMIOLOGY www.jasn.org Population Income and Longitudinal Trends in Living Kidney Donation in the United States

Living kidney donation is declining in theUnited States.Weexamined longitudinal trends in living donation as a function of median household income and donor relation to assess the effect of financial barriers on donation in a changing economic environment. The zip code–level median household income of all 71,882 living donors was determined by linkage to the 2000 US Census. Longitudinal changes in the rate of donation were determined in income quintiles between 1999 and 2004, when donations were increasing, and between 2005 and 2010, when donations were declining. Rates were adjusted for population differences in age, sex, race, and ESRD rate using multilevel linear regression models. Between 1999 and 2004, the rate of growth in living donation per million population was directly related to income, increasing progressively from the lowest to highest incomequintile, with annualized changes of 0.55 (95% confidence interval [95% CI], 0.14 to 1.05) for Q1 and 1.77 (95% CI, 0.66 to 2.77) for Q5 (P,0.05). Between 2005 and 2010, donation declined in Q1, Q2, and Q3; was stable in Q4; and continued to grow in Q5. Longitudinal changes varied by donor relationship, and the association of income with longitudinal changes also varied by donor relationship. In conclusion, changes in living donation in the past decade varied by median household income, resulting in increased disparities in donation between lowand high-income populations. These findings may inform public policies to support living donation during periods of economic volatility. J Am Soc Nephrol 26: ccc–ccc, 2014. doi: 10.1681/ASN.2014010113 For patients with ESRD, living-donor kidney transplantation is the preferred therapy because it allows for timely transplantation and is associated with superior outcomes compared with deceased-donor transplantation or dialysis.1,2 The expanded use of living-donor transplantation in the 1990s (a 125% increase between 1990 and 19993) was an important strategy to address the increasing demand for kidney transplantation, while efforts to expand deceased-donor kidney transplantation provided a more modest (10%3) increase in transplantable organs during the same time period. Since 2005, however, living-donor transplantation has declined in the United States for uncertain reasons. Given that lower-incomepopulations have lower rates of live kidney donation4 and .20% of living kidney donors report financial hardship after donation,5 it is possible that the financial implications of living donation may have contributed to the decline in living-donor transplantation. The costs of living donation include travel, lodging, and services, such as child or elder care, as well as lost wages. Costs as high as $20,000 have been reported, with an average estimated cost of $5000.6 Although many states have developed mechanisms to at least partially reimburse these costs, these initiatives have been inconsistently associated with an increase in living donation.7 To further understand Received January 30, 2014. Accepted May 17, 2014. Published online ahead of print. Publication date available at www.jasn.org. Correspondence: Dr. Jagbir Gill, University of British Columbia, St. Paul’s Hospital, Providence Building, Ward 6a, 1081 Burrard Street, Vancouver, BCV6Z1YZ,Canada. Email: jagill@providencehealth. bc.ca Copyright © 2014 by the American Society of Nephrology J Am Soc Nephrol 26: ccc–ccc, 2014 ISSN : 1046-6673/2601-ccc 1 the recent retraction in living donation and inform future health policy initiatives to address the financial costs of living donation, we determined the association of donor income with longitudinal changes in living kidney donation.