Supplementary Material for: Age- and Sex-Specific Reference Values of Estimated Glomerular Filtration Rate in Chinese Population

Background: Due to an aging population, prevalence and mortality of CKD continue to increase. Current CKD definition has been challenged recently. Age- and sex-specific reference values of estimated glomerular filtration rate (eGFR) in China are still lacking. Methods: Age- and sex-stratified, randomly selected inhabitants received a health examination and an inquest into medical history. The GFR was estimated using CKD-EPI equation. We calculated means with ±1.96 times of standard deviation and 2.5th, 97.5th percentiles of eGFR per 5-year age-group. Some of their GFRs were measured by the Gates method (99mTc-DTPA renal scintigraphy) and estimated by cystatin C-based equation. Results: The cohort study included 17,037 male and 9,304 female Chinese persons aged 18–99 years. A reference population of apparently healthy subjects was selected by excluding persons with known hypertension, diabetes, cardiovascular, or renal diseases. This healthy cohort study included 12,231 male subjects and 6,463 female subjects. The mean eGFR was higher in the female than that in the male who were younger than 40-year (122 mL/min/1.73 m2 vs. 111 mL/min/1.73 m2). In these apparently healthy persons, GFR declined approximately 0.8 mL/min/year. The lower limit of eGFR (2.5th percentile or mean minus 1.96 times of standard deviation) was <60 or 45 mL/min/1.73 m2 at the age of ≥40 or 65 years old, respectively. Conclusion: The mean eGFR was higher in young females. GFR declined approximately 0.8 mL/min/year. The lower bound of eGFR was <60 mL/min/1.73 m2 or 45 mL/min/1.73 m2 at the age of ≥40 or ≥65 years, respectively. Our study provides age- and sex-specific reference values of GFR in a Chinese population.

Background: 随着人口老龄化加剧，慢性肾脏病（Chronic Kidney Disease, CKD）的患病率与病死率持续攀升。当前通用的CKD定义近期受到学界质疑，而中国人群中针对年龄与性别的估算肾小球滤过率（estimated glomerular filtration rate, eGFR）参考值仍存在空白。
Methods: 本研究采用年龄与性别分层的随机抽样方法，选取符合要求的居民接受健康体检与病史问询。采用CKD-EPI公式估算肾小球滤过率（glomerular filtration rate, GFR），按每5岁年龄组计算eGFR的均值±1.96倍标准差，以及2.5百分位、97.5百分位数值。部分受试者的GFR通过Gates法（99m锝-二乙三胺五醋酸肾闪烁显像）测定，并采用基于胱抑素C的公式进行估算。
Results: 本队列研究共纳入18至99岁的中国受试者17037名男性与9304名女性。通过排除已知患有高血压、糖尿病、心血管疾病或肾脏疾病者，筛选出表观健康人群作为参考队列，该健康队列共纳入12231名男性与6463名女性。在40岁以下人群中，女性的平均eGFR高于男性（122 mL/min/1.73m² 对比 111 mL/min/1.73m²）。在该表观健康队列中，GFR每年约下降0.8 mL/min。当年龄≥40岁或≥65岁时，eGFR的下限（2.5百分位值或均值-1.96倍标准差）分别低于60 mL/min/1.73m²与45 mL/min/1.73m²。
Conclusion: 年轻女性的平均eGFR水平更高。GFR每年约下降0.8 mL/min。当年龄≥40岁或≥65岁时，eGFR的下限分别低于60 mL/min/1.73m²与45 mL/min/1.73m²。本研究为中国人群提供了基于年龄与性别的GFR参考值。