Effects of Age and Race on GFR Estimation in a Population-based Cohort

本方案将在约翰霍普金斯临床中心基于人群的多种族动脉粥样硬化研究（梅萨）队列的375名黑人和白色成人受试者中，评价两种GFR标志物（肌酐和胱抑素C）与通过碘海醇清除率测量的肾小球滤过率（GFR）相比的效用。虽然在过去的十年中，通过肌酐估计GFR有所改善，但65岁以上人群的纳入不足，并且在美国黑人和白人的人群样本中没有进行GFR测量的研究。为了在广泛的年龄范围内推进CKD的检测和定义，我们必须关注GFR的较高范围，并且我们必须确定GFR估计的最佳策略。本横断面研究的第一个目的是确定黑人种族对一般人群中滤过标志物（肌酐和胱抑素C）血清水平的影响，并修改当前GFR方程，以最佳方式捕获黑人种族的影响。第二个目标是：评价与年龄相关的GFR下降;比较滤过标志物捕获随年龄下降的GFR的相对能力;以及修改当前GFR方程以纳入年龄的影响。在执行这些目标时，我们将确定用于GFR估计的最佳生物标志物：肌酐、胱抑素C或两者。此外，将储存血液标本，以便将来检查滤过标志物。为了实现我们的目标，我们将测量约375名黑人和白色梅萨参与者的碘海醇-GFR，目标年龄范围为55-95岁。这项研究可能是国家卫生研究所努力解决美国肾脏疾病负担中持续存在的种族差异的主要贡献者。

This protocol will evaluate the utility of the two GFR markers, creatinine and cystatin C, in comparison with measured glomerular filtration rate (GFR) by iohexol clearance in 375 Black and White adult participants of the population-based Multi-ethnic Study of Atherosclerosis (MESA) cohort from the Johns Hopkins clinical center. Although GFR estimation by creatinine has improved over the past decade, there has been inadequate inclusion of persons over 65 years of age, and no study of GFR measurement has occurred within a population-based sample of Blacks and Whites in the United States. To advance the detection and definition of CKD across a broad age range of diverse adults,, we must focus on the higher ranges of GFR, and we must identify the optimal strategy for GFR estimation. The first Aim of this cross-sectional study will be to determine the influence of Black race-ethnicity on serum levels of filtration markers (creatinine and cystatin C) in the general population, and to modify current GFR equations to capture optimally the influence of Black race. The second Aim will be: to evaluate age-related decline in GFR; to compare the relative ability of the filtration markers to capture declining GFR with age; and, to modify current GFR equations to incorporate the influence of age. In executing these Aims, we will determine the optimal biomarker(s) for GFR estimation ¿ creatinine, cystatin C, or both. In addition, blood specimens will be stored with the potential for examination of future filtration markers. To accomplish our objectives, we will measure iohexol-GFR in approximately 375 Black and White MESA participants, spanning a target age range of 55-95. This study could be a major contributor to the National Institute of Health¿s efforts to address the persistent racial disparities in the burden of kidney disease in the United States.