Department of Medicine, Division of Nephrology and Hypertension and The Kidney Institute, University of Kansas Medical Center, Kansas City, KS 66160, USA.
Nephrol Dial Transplant. 2011 Jul;26(7):2222-31. doi: 10.1093/ndt/gfq695. Epub 2010 Nov 23.
The association between estimated glomerular filtration rate (eGFR) and progression of Alzheimer disease (AD), as measured by cognitive decline and brain atrophy, has been infrequently studied. Since AD is characterized by sarcopenia and other changes in body composition, which are known to influence GFR, a determination of how lean mass (LM) affects estimation of GFR in AD patients is important.
Participants were drawn from a prospective longitudinal study of brain ageing and AD in community-dwelling individuals. Control (n = 60) and AD (n = 61) participants were enrolled. Estimated GFR was calculated using the four-variable Modification of Diet in Renal Disease (MDRD), Cockroft-Gault, Macdonald appendicular LM and Taylor LM equations. Association of eGFR with 2-year change in cognitive function and brain volume was assessed.
Individuals with AD demonstrated a paradoxical finding in which lower baseline MDRD eGFR was associated with less cognitive decline (P = 0.04) and brain atrophy (P = 0.02), a phenomenon not observed in non-AD controls. This finding was abolished in the AD patients when either the Macdonald appendicular LM or Taylor LM equations were used. While significant group-by-eGFR interactions were present for cognitive decline (P = 0.006) and brain atrophy (P = 0.001) when the MDRD equation was used, no group-by-eGFR interactions were present when either the Macdonald LM (P = 0.58 and P = 0.10 for cognitive decline and brain atrophy, respectively) or Taylor LM (P = 0.97 and P = 0.55) equations were used.
Accounting for measures of LM in GFR estimation appears to significantly mitigate counterintuitive relationships between measures of AD progression and eGFR as calculated by more traditional measures of renal function. This suggests that consideration of LM in eGFR calculations may be important in patients with sarcopenia, such as the AD population.
通过认知能力下降和脑萎缩来衡量，估算肾小球滤过率（eGFR）与阿尔茨海默病（AD）进展之间的关联研究甚少。由于 AD 以肌肉减少症和身体成分的其他变化为特征，这些变化已知会影响 GFR，因此确定瘦体重（LM）如何影响 AD 患者 GFR 的估计值非常重要。
参与者来自一项针对社区居住个体的大脑衰老和 AD 的前瞻性纵向研究。纳入了对照组（n = 60）和 AD 组（n = 61）参与者。使用四变量改良肾脏病饮食研究（MDRD）、 Cockcroft-Gault、Macdonald 四肢 LM 和 Taylor LM 方程计算估计的 GFR。评估 eGFR 与 2 年认知功能和脑容量变化的相关性。
AD 患者的基线 MDRD eGFR 较低与认知能力下降（P = 0.04）和脑萎缩（P = 0.02）的相关性较小，这是一种在非 AD 对照组中未观察到的现象。当使用 Macdonald 四肢 LM 或 Taylor LM 方程时，这种现象在 AD 患者中消失了。虽然当使用 MDRD 方程时，认知能力下降（P = 0.006）和脑萎缩（P = 0.001）的组间 eGFR 交互作用显著，但当使用 Macdonald LM 时，无组间 eGFR 交互作用（P = 0.58 和 P = 0.10，用于认知能力下降和脑萎缩）或 Taylor LM（P = 0.97 和 P = 0.55）方程。
在 GFR 估计中考虑 LM 测量值似乎可以显著减轻 AD 进展和更传统的肾功能测量值计算得出的 eGFR 之间的反直觉关系。这表明在肌肉减少症患者（如 AD 患者）中，考虑 eGFR 计算中的 LM 可能很重要。
