Understanding normal aging of kidney function is pivotal to help distinguish individuals at particular risk for chronic kidney disease. Glomerular filtration rate (GFR) is typically estimated via serum creatinine (eGFRcrea) or cystatin C (eGFRcys). Since population-based age-group-specific reference values for eGFR and eGFR-decline are scarce, we aimed to provide such reference values from population-based data of a wide age range. In four German population-based cohorts (KORA-3, KORA-4, AugUR, DIACORE), participants underwent medical exams, interview, and blood draw up to five times within up to 25 years. We analyzed eGFRcrea and eGFRcys cross-sectionally and longitudinally (12,000 individuals, age 25-95 years). Cross-sectionally, we found age-group-specific eGFRcrea to decrease approximately linearly across the full age range, for eGFRcys up to the age of 60 years. Within age-groups, there was little difference by sex or diabetes status. Longitudinally, linear mixed models estimated an annual eGFRcrea decline of -0.80 [95% confidence interval -0.82, -0.77], -0.79 [-0.83, -0.76], and -1.20 mL/min/1.73m [-1.33, -1.08] for the general population, “healthy” individuals, or individuals with diabetes, respectively. Reference values for eGFR using cross-sectional data were shown as percentile curves for “healthy” individuals and for individuals with diabetes. Reference values for eGFR-decline using longitudinal data were presented as 95% prediction intervals for “healthy” individuals and for individuals with diabetes, obesity, and/or albuminuria. Thus, our results can help clinicians to judge eGFR values in individuals seen in clinical practice according to their age and to understand the expected range of annual eGFR-decline based on their risk profile.

中文翻译：

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25 至 95 岁无糖尿病和糖尿病德国人肾功能和肾功能下降的人群参考值


了解肾功能的正常衰老对于帮助区分具有慢性肾病特别风险的个体至关重要。肾小球滤过率 （GFR） 通常通过血清肌酐 （eGFRcrea） 或胱抑素 C （eGFRcys） 来估计。由于 eGFR 和 eGFR 下降的基于人群的年龄组特异性参考值很少，我们旨在从广泛年龄范围的基于人群的数据中提供此类参考值。在四个德国人群队列（KORA-3、KORA-4、AugUR、DIACORE）中，参与者在长达 25 年内接受了多达五次的体检、访谈和抽血。我们分析了 eGFRcrea 和 eGFRcys 的横断面和纵向 （12,000 人，年龄 25-95 岁）。在横断面上，我们发现年龄组特异性 eGFRcrea 在整个年龄范围内大致呈线性下降，适用于 60 岁以下的 eGFRcys。在年龄组内，性别或糖尿病状况几乎没有差异。纵向线性混合模型估计，普通人群、“健康”个体或糖尿病个体的年平均 eGFRcrea 下降分别为 -0.80 [95% 置信区间 -0.82， -0.77]、-0.79 [-0.83， -0.76] 和 -1.20 mL/min/1.73m [-1.33， -1.08]。使用横断面数据的 eGFR 参考值显示为“健康”个体和糖尿病个体的百分位曲线。使用纵向数据的 eGFR 下降参考值表示为 “健康” 个体和糖尿病、肥胖和/或白蛋白尿个体的 95% 预测区间。因此，我们的结果可以帮助临床医生根据年龄判断临床实践中观察到的个体的 eGFR 值，并根据他们的风险状况了解每年 eGFR 下降的预期范围。