Demographic and clinical characteristics associated with glomerular filtration rates in living kidney donors

Abstract

Due to the shortage of organs, living donor acceptance criteria are becoming less stringent. An accurate determination of the glomerular filtration rate (GFR) is critical in the evaluation of living kidney donors and a value exceeding 80ml/min per 1.73m2 is usually considered suitable. To improve strategies for kidney donor screening, an understanding of factors that affect GFR is needed. Here we studied the relationships between donor GFR measured by 125I-iothalamate clearances (mGFR) and age, gender, race, and decade of care in living kidney donors evaluated at the Cleveland Clinic from 1972 to 2005. We report the normal reference ranges for 1057 prospective donors (56% female, 11% African American). Females had slightly higher mGFR than males after adjustment for body surface area, but there were no differences due to race. The lower limit of normal for donors (5th percentile) was less than 80 ml/min per 1.73m2 for females over age 45 and for males over age 40. We found a significant doubling in the rate of GFR decline in donors over age 45 as compared to younger donors. The age of the donors and body mass index increased over time, but their mGFR, adjusted for body surface area, significantly declined by 1.49±0.61 ml/min per 1.73m2 per decade of testing. Our study shows that age and gender are important factors determining normal GFR in living kidney donors.

Age-specific distribution of estimated glomerular filtration rate using Japanese health checkup data

“…During its development and validation, Matsuo et al 2) mentioned that the eGFR according to the Japanese GFR equation might not be applicable to the healthy population, because the equation was derived mostly from patients with CKD. Some studies assessed the bias of the above equation by comparing eGFR and measured GFR (mGFR) in renal transplant donor candidates 13,14) . Horio et al described that eGFR was significantly lower than mGFR in potential kidney donors 14) .…”

Evaluation of Kidney Function and Structure in Potential Living Kidney Donors: Implications for the Donor and Recipient

“…In a cross-sectional study, Rule et al [24] reported that GFR decreases at a rate of about 4 mL/min/ 1.73 m 2 per decade of life in prospective donors. Poggio et al [4] also reported that GFR declines at a rate of approximately 4 mL/min/1.73 m 2 per decade of life in donors aged 45 years or younger but the GFR decreases at a faster rate (approximately 8 mL/min/1.73 m 2 per decade) in older donors. Sex and race appear not to be determinants of GFR.…”

“…Recent practice in the USA reveals that approximately 67 % of transplant centers use the straight cut-off value of 80 mL/min to accept donors, while 25 % use an age-and sex-based approach [12]. It is necessary to emphasize that because GFR is known to decline with aging, the lower limit of normal GFR in subjects medically cleared to donate a kidney is variable [4]. This is an important issue to keep in mind when evaluating young donors, as a simple cut-off of 80 mL/min may represent low kidney function in such a candidate.…”

“…The spectrum of health in accepted donors with isolated medical abnormalities has ranged from subtle metabolic abnormalities to early pre-clinical disease states that may portend future risk [2]. In fact, contemporary donors are older, heavier, and carry more risk factors for chronic kidney disease than donors in earlier generations [3][4][5]. Additionally, recent data suggesting that live kidney donors have higher rates of end-stage renal disease in the long-term compared with otherwise similar healthy persons [6••, 7] highlights the importance of careful predonation selection, including assessment of renal function and structure as critical components of the donor evaluation.…”

GFR Estimating Equations

“…The problem with defining CKD by abnormal levels of GFR is that the GFR threshold varies by method. For example, the fifth percentile for eGFR Cr is about 10 to 15 ml/min per 1.73 m 2 lower than the fifth percentile for mGFR (50). We would define CKD by an elevated serum creatinine level relative to a health-associated reference ranges (e.g., 0.6-1.1 mg/dl in women and 0.8-1.3 mg/dl in men).…”