The Assessing Long Term Outcomes in Living Kidney Donors (ALTOLD) multicenter/multisite studysuccessfully enrolled 200 pairs of living kidney donors and equally healthy two-kidney controls starting in July2006. ALTOLD measured iohexol glomerular filtration rate (GFR) and traditional cardiovascular disease (CVD)risk factors pre- and 6, 12, 24 and 36 months post-donation. ALTOLD continues to answer important questionsregarding the safety and the science of living kidney donation not addressed in previous uncontrolled crosssectionalstudies. Important preliminary short-term results include the fact that GFR (slopes) increasedbetween 6 and 36 months in donors v. controls, and that serum parathyroid hormone and uric acid levels haveincreased in donors v. controls. It is critically important to maintain these valuable cohorts to continuemeasuring trends in GFR and traditional CVD risk factors, and address new questions. The current proposalwill conduct 6-year and begin 9-year follow-up visits. Long-term follow up will allow us to confirm the safety ofkidney donation, and allow us to address a number of important scientific questions that have broadimplications in our understanding of chronic kidney disease (CKD). ALTOLD will help determine whether theabnormalities associated CKD in observational studies are the cause or the result of the CKD. ALTOLD willtest the hypothesis that GFR declines with age in normal, healthy individuals, and that unilateral nephrectomyaccelerates this decline (Aim 1). It will also test the hypothesis that mild reductions in kidney function lead tochronic changes in mineral and bone disorders and other key CKD biomarkers in kidney donors (Aim 2).Finally, ALTOLD will test the hypothesis that mild declines in GFR affect arterial compliance (Aim 3).Specifically, ALTOLD will measure aortic pulse wave velocity, which has been shown to correlate with CVD inpatients with CKD, as well as small and large artery elasticity using applanation tonometry at the 6-year visit inboth donors and controls. In summary, it is critical to capitalize on the short- term investment in ALTOLD withuninterrupted long-term follow up that will minimize participant dropout and maximize the knowledge we willgain from this valuable cohort.
