Viktorsdottir Olof, Palsson Runolfur, Andresdottir Margret B, Aspelund Thor, Gudnason Vilmundur, Indridason Olafur S
University of Iceland Faculty of Medicine, Reykjavik, Iceland.
Nephrol Dial Transplant. 2005 Sep;20(9):1799-807. doi: 10.1093/ndt/gfh914. Epub 2005 May 31.
The purpose of this study was to compare three different equations to calculate estimated glomerular filtration rate (eGFR) based on serum creatinine (SCr) and to estimate the prevalence of chronic kidney disease (CKD) in the Icelandic population.
This was a cross-sectional study using data from the Reykjavik Heart Study. GFR was estimated with three equations: Equation I was based on 1/SCr; Equation II based on the Cockcroft-Gault equation; and Equation III was the modified MDRD equation. The eGFR calculated with Equation III and proteinuria were used to estimate the prevalence of CKD. The prevalence was age-standardized to the truncated world population. We used chi-square and ANCOVA to compare the group with low eGFR to age-matched controls.
The subjects consisted of 9229 males and 10,027 females, aged 33-85 years. The equations performed very differently. Equation I showed women with higher eGFR than men and little change with age. Equation II showed men with higher eGFR than women and marked decline in eGFR with age. Equation III was similar to Equation II but the decline in eGFR with age was not as great. Regardless of the equation used, most subjects (63.7-80.7%) had an eGFR in the range of 60-89 ml/min/1.73 m2. Using Equation III, age-standardized prevalence of low eGFR for the population aged 35-80+ years was estimated to be 4.7 and 11.6% for men and women, respectively. The proportion of subjects with eGFR <60 ml/min/1.73 m2 increased with advancing age. An additional 2.39% of men and 0.89% of women had proteinuria. The prevalence of renal and cardiovascular risk factors including proteinuria, hypertension, lipid abnormalities and markers of inflammation was higher among those with low eGFR than age-matched controls.
GFR estimates and the prevalence of CKD are dependent on the equation used to calculate eGFR. Unexpectedly, a low proportion of the Icelandic population had normal kidney function according to the eGFR regardless of the equation used. These equations may not be useful in epidemiological research.
本研究旨在比较三种基于血清肌酐（SCr）计算估计肾小球滤过率（eGFR）的不同方程，并估算冰岛人群中慢性肾脏病（CKD）的患病率。
这是一项横断面研究，使用了雷克雅未克心脏研究的数据。用三种方程估算肾小球滤过率：方程I基于1/SCr；方程II基于Cockcroft-Gault方程；方程III是改良的MDRD方程。用方程III计算的eGFR和蛋白尿来估算CKD的患病率。患病率按年龄标准化为截短的世界人口。我们用卡方检验和协方差分析将低eGFR组与年龄匹配的对照组进行比较。
研究对象包括9229名男性和10027名女性，年龄在33 - 85岁之间。这些方程的表现差异很大。方程I显示女性的eGFR高于男性，且随年龄变化不大。方程II显示男性的eGFR高于女性，且eGFR随年龄显著下降。方程III与方程II相似，但eGFR随年龄的下降幅度没那么大。无论使用哪种方程，大多数受试者（63.7 - 80.7%）的eGFR在60 - 89 ml/min/1.73 m²范围内。使用方程III，35 - 80岁及以上人群中，男性和女性低eGFR的年龄标准化患病率分别估计为4.7%和11.6%。eGFR<60 ml/min/1.73 m²的受试者比例随年龄增长而增加。另外，2.39%的男性和0.89%的女性有蛋白尿。在低eGFR人群中，包括蛋白尿、高血压、血脂异常和炎症标志物在内的肾脏和心血管危险因素患病率高于年龄匹配的对照组。
GFR估计值和CKD患病率取决于用于计算eGFR的方程。出乎意料的是，无论使用哪种方程，根据eGFR，冰岛人群中肾功能正常的比例都很低。这些方程可能在流行病学研究中不太有用。
