Effect of Obesity on Long-term Clinical Outcomes After Kidney Donation

Study Summary

Several studies have shown that renal function in patients who have donated a kidney (but are otherwise healthy) remains stable and within normal limits. However, it is unclear how donor nephrectomy affects patient subsets with comorbidities, an issue that becomes relevant in the current environment where inclusion criteria are continuously becoming less stringent and more patients are being considered as potential donors. In the present study, the investigators plan to evaluate long-term renal function in obese patients who have donated a kidney as part of a living donor renal transplant procedure. The investigators have selected this group because it is at higher risk for developing obesity-related complications such as diabetes and hypertension that may impair renal function, it is rapidly becoming a major subgroup in the kidney donor population, and no studies have systematically followed obese patients after kidney donation. Establishment of an appropriate control group is of primary importance in studies examining long-term outcomes. The investigators will also evaluate a 2-kidney control group to allow us to compare the individual and interactive effects of obesity and kidney donation on long-term renal function. Study participants will complete a medical questionnaire, undergo blood pressure measurements, and provide blood and urine samples for analysis of various metabolic parameters. Some study participants will have ambulatory blood pressure monitoring performed which involves application of an automated blood pressure cuff for 24 hours. Some study participants will also undergo direct measurements of glomerular filtration rate (GFR) with iohexol. In the proposed research, the investigators hypothesize that obesity in kidney donors increases the likelihood of developing renal dysfunction and risk factors for cardiovascular disease (CVD) and may increase the likelihood even more than in healthy controls.