Scarr Daniel, Bjornstad Petter, Lovblom Leif E, Lovshin Julie A, Boulet Genevieve, Lytvyn Yuliya, Farooqi Mohammed A, Lai Vesta, Orszag Andrej, Weisman Alanna, Keenan Hillary A, Brent Michael H, Paul Narinder, Bril Vera, Cherney David Z I, Perkins Bruce A
Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
Division of Endocrinology, Department of Pediatrics, University of Colorado, Aurora, Colorado, USA.
Kidney Int Rep. 2019 Feb 21;4(6):786-796. doi: 10.1016/j.ekir.2019.02.010. eCollection 2019 Jun.
Glomerular filtration rate (GFR) is routinely used for clinical assessment of kidney function. However, the accuracy of estimating equations in older adults is uncertain.
In 66 adults with ≥50 years type 1 diabetes (T1D) duration and 73 nondiabetic controls from age/sex-matched subgroups (65 ± 8 years old and 77[55%] were women) we evaluated the performance of estimated GFR (eGFR) by creatinine (Modification of Diet and Renal Disease [MDRD], Chronic Kidney Disease-Epidemiology [CKD-EPI]), cystatin C (CKD-EPI, CKD-EPI), and β-microglobulin (β2M) compared with measured GFR by inulin clearance (mGFR). Performance was evaluated using metrics of bias (mean difference), precision (SD), and accuracy (proportion of eGFR that differed by >20% of mGFR).
Mean mGFR was 104 ± 18 ml/min per 1.73 m (range: 70-154 ml/min per 1.73 m) and was not different between T1D and controls (103 ± 17 vs. 105 ± 19 ml/min per 1.73 m, 0.39). All equations significantly underestimated mGFR (bias: -15 to -30 ml/min per 1.73 m, < 0.001 for all comparisons) except for β2M, which had bias of 1.9 ml/min per 1.73 m ( 0.61). Bias was greatest in cystatin C-based equations. Precision was lowest for β2M (SD: 43.5 ml/min per 1.73 m, < 0.001 for each comparison). Accuracy was lowest for CKD-EPI (69.1%, < 0.001 for each comparison). Cystatin C-based equations demonstrated greater bias and lower accuracy in older age subgroups (<60, 60-69, ≥70 years). All equations demonstrated greater bias across higher ranges of mGFR (60-89, 90-119, ≥120 ml/min per 1.73 m). Results were similar between T1D and controls except that β2M had lower performance in T1D.
Better estimates of GFR in older adults are needed for research and clinical practice, as this subgroup of the population has an amplified risk for the development of chronic kidney disease (CKD) that requires accurate GFR estimation methods.
肾小球滤过率（GFR）常用于临床肾功能评估。然而，老年人估算方程的准确性尚不确定。
在66名1型糖尿病（T1D）病程≥50年的成年人和73名年龄/性别匹配亚组的非糖尿病对照者（65±8岁，77名[55%]为女性）中，我们评估了基于肌酐（饮食改良与肾病[MDRD]、慢性肾脏病流行病学协作组[CKD-EPI]）、胱抑素C（CKD-EPI、CKD-EPI）和β-微球蛋白（β2M）的估算GFR（eGFR）与菊粉清除率测量的GFR（mGFR）相比的性能。使用偏倚（平均差异）、精密度（标准差）和准确性（eGFR与mGFR相差>20%的比例）指标评估性能。
平均mGFR为每1.73平方米104±18毫升/分钟（范围：每1.73平方米70 - 154毫升/分钟），T1D患者和对照者之间无差异（每1.73平方米103±17 vs. 105±19毫升/分钟，P = 0.39）。除β2M外，所有方程均显著低估了mGFR（偏倚：每1.73平方米-15至-30毫升/分钟，所有比较P < 0.001），β2M的偏倚为每1.73平方米1.9毫升/分钟（P = 0.61）。基于胱抑素C的方程偏倚最大。β2M的精密度最低（标准差：每1.73平方米43.5毫升/分钟，每次比较P < 0.001）。CKD-EPI的准确性最低（69.1%，每次比较P < 0.001）。基于胱抑素C的方程在老年亚组（<60岁、60 - 69岁、≥70岁）中表现出更大的偏倚和更低的准确性。所有方程在较高mGFR范围（每1.73平方米60 - 89、90 - 119、≥120毫升/分钟）内均表现出更大的偏倚。T1D患者和对照者的结果相似，只是β2M在T1D患者中的性能较低。
对于研究和临床实践而言，需要更好地估算老年人的GFR，因为该人群亚组发生慢性肾脏病（CKD）的风险增加，这需要准确的GFR估算方法。
