UNDERSTANDING POST-DONATION KIDNEY FUNCTION IN LIVING KIDNEY DONORS

Living donors provide a third of the kidney transplants each year in the United States. Because donor nephrectomy is truly elective, transplant providers must offer personalized risk estimates to people considering kidney donation, as well as individualized post-donation care. This dissertation focuses on post-donation kidney function and the association of early post-donation outcomes with recipient graft outcomes. First, since hypertension and diabetes are the predominant causes of end-stage renal disease (ESRD) in living kidney donors, we sought to clarify their early post-donation incidence rates (Chapter 2). Using national registry data, we estimated 310 per 10,000 donors developed hypertension within 2-years of donation, while only 15 per 10,000 donors developed diabetes. We then focused on hypertension and obesity and their association with post-donation renal function (Chapters 3 and 4). We compared a cohort of 1295 donors to a weighted cohort of 8233 healthy non-donors. We found that kidney donation was independently associated with a 19% higher risk of hypertension and that donors who developed hypertension had a plateau in the usual post-donation increase of estimated glomerular filtration rate (eGFR). We also found that donor eGFR trajectory varied by obesity. Non-obese donors had an increase in eGFR of +0.55 mL/min/year while obese donors had an attenuated increase of +0.30 mL/min/year. In comparison, obese and non-obese non-donors had a similar decrease in eGFR over time. Finally, we studied early post-donation markers of donor renal function and recipient graft outcomes using national registry data (Chapters 5 and 6). Given that donor ESRD is associated with recipient graft loss, we found that the risk of recipient graft loss increased with each decrement in 6-month post-donation eGFR. Last, although hypertension is a frequent causes of donor ESRD, we found iii that recipients whose donors developed incident hypertension within 2-years post-donation had no higher risk of graft loss. Our results will be used by nephrologists and transplant surgeons to better personalize counseling for people considering living kidney donation as well as better individualize post-donation care