A Prospective Observational Study of Changes in Renal Function and Cardiovascular Risk Following Living Kidney Donation G.V. Ramesh Prasad, 1,2,3 Deborah Lipszyc, 2 Michael Huang, 2 Michelle M. Nash, 2 and Lindita Rapi 2 The effect of unilateral nephrectomy on the cardiovascular risk profile of living kidney donors has not been prospec- tively studied. We performed an observational cohort study of 58 living donors to 6 months postdonation for changes in 24-hr ambulatory blood pressure profiles, renal function, urine protein excretion, body mass index, glucose toler- ance, and fasting lipid profiles. The 24-hr systolic blood pressure average and night-day ratio were unchanged from pre- to postdonation (118.911 vs. 118.114 mm Hg, P=0.77; 0.870.07 vs. 0.870.09, P=0.68, respectively). Estimated glomerular filtration rate declined from 91.916 to 61.612 mL/min/1.73 m 2 (P0.0001). Protein excre- tion, body mass index, glucose, and lipids were unchanged. No significant differences were noted between dippers and nondippers either pre- or postdonation. In summary, living kidney donation in the short term is safe. We suggest further observation of individuals with lower glomerular filtration rate for possible increased cardiovascular risk factors in the future. Keywords: Cardiovascular risk, Nephrectomy, Living donors, Ambulatory blood pressure, Renal function, Protein- uria, Kidney donation. (Transplantation 2008;86: 1315–1318) L iving kidney donors undergo unilateral nephrectomy without medical benefit. The procedure is considered ac- ceptably safe (1–9), which is a paradigm based predominantly on retrospective, cross-sectional studies prone to selection and information bias (10). Subtle evolution of cardiovascular risk factors such as blood pressure (BP) elevation and hypertension (11), decline in kidney function and chronic renal insufficiency (12), and de novo proteinuria (12) may therefore be undetected. There is also concern about circadian BP rhythm disturbance, which may occur with kidney function loss less than required for hypertension (13), and likewise, there is also concern about de- velopment of the metabolic syndrome (14). The purpose of this prospective, observational study was to describe changes in BP, renal function, and urinary protein excretion to 6 months postdonation. In addition, we describe the short-term natural history of additional markers of cardiovascular risk including the body mass index (BMI), the fasting lipid profile, and glucose metabolism in a prospec- tively assembled cohort of living kidney donors. METHODS Our hospital performs approximately 100 renal trans- plants annually, of which one half are derived from living donors. Presurgical evaluation includes excluding hyperten- sion by office BP measurement (140/90 mm Hg) and 24-hr ambulatory BP (ABP) monitoring (135/85 mm Hg); renal insufficiency: estimated glomerular filtration rate (eGFR) (70 mL/min/1.73 m 2 ); proteinuria (300 mg/24 hr); dia- betes (fasting blood glucose7.0 mmol/L and/or 2-hr blood glucose11.1 mmol/L on 75 g oral glucose tolerance testing); and morbid obesity (BMI40 kg/m 2 ). Nephrolithiasis and surgical contraindications are excluded through abdominal computerized tomography. Standard postdonation evalua- tion includes an office visit 3 months postdonation, during which a sphygmomanometer-measured BP is obtained, renal function is estimated by the abbreviated Modification of Diet in Renal Disease (MDRD) equation (15), and a random urine sample is evaluated for proteinuria. All potential donors re- ceiving prior approval to donate by an independent team were approached for participation. This study was funded by the Dean’s Fund new staff grant program at the University of Toronto, Canada. 1 Division of Nephrology, University of Toronto, St. Michael’s Hospital, Toronto, ON, Canada. 2 Renal Transplant Program, St. Michael’s Hospital, Toronto, ON, Canada. 3 Address correspondence to: G.V. Ramesh Prasad, M.B., B.S., M.Sc., F.R.C.P.(C), F.A.C.P., Division of Nephrology, University of Toronto, St. Michael’s Hospital, 61 Queen Street East, 9th Floor, Toronto, ON M5C 2T2, Canada. E-mail: prasadr@smh.toronto.on.ca Received 27 June 2008. Accepted 7 July 2008. Copyright © 2008 by Lippincott Williams & Wilkins ISSN 0041-1337/08/8609-1315 DOI: 10.1097/TP.0b013e318188425b TABLE 1. Demographic characteristics of study population Age, yrs (meanSD, 95% CI) 45.311 (42–48) Gender (M/F) 12/46 Smoker (Y/N) 6/52 Ethnicity White 38 Black 5 East Asian 8 South Asian 5 Other 2 Relation to recipient Parent 5 Sibling 9 Child 5 Spouse/partner 27 Friend 12 Transplantation • Volume 86, Number 9, November 15, 2008 1315