Godfrey T, Cuadrado M J, Fofi C, Abbs I, Khamashta M A, Nunan T, Hughes G R
Lupus Research Unit, The Rayne Institute, St Thomas' Hospital, London SE1 7EH, UK.
Rheumatology (Oxford). 2001 Mar;40(3):324-8. doi: 10.1093/rheumatology/40.3.324.
To investigate whether the ethylenediamine tetraacetic acid (EDTA) glomerular filtration rate (GFR) is a better indicator of the degree of renal involvement than serum creatinine concentration or creatinine clearance calculated by the Cockroft-Gault formula.
We studied prospectively all systemic lupus erythematosus (SLE) patients with normal or borderline serum creatinine concentration (<110 micromol/l) and urinary sediment abnormalities and/or proteinuria in the last 2 yr. EDTA-GFR, serum creatinine concentration, calculated creatinine clearance (Cockroft-Gault formula) and 24-h urine protein were determined at the same time. Renal biopsies were performed in patients with low values of EDTA-GFR or significant proteinuria.
Twenty-three patients were identified, of whom 22 were females. The average age of the patients was 31.6+/-8.2 yr. Biopsies were assigned to WHO classes as follows: class II, 1 patient; class III, 6 patients; class IV, 10 patients; class V, 6 patients. The average serum creatinine concentration, EDTA-GFR and calculated creatinine clearance were 79.8+/-mol/l, 74.5 ml/min and 97 ml/min respectively. EDTA-GFR showed abnormal values (<80 ml/min) in 15 of the 23 patients (65.2%) while calculated creatinine clearance was abnormal (<80 ml/min) in three of the 23 patients (13%) (P<0.001). Using the Pearson correlation test, we did not find any correlation between EDTA-GFR or creatinine clearance values and the sum of activity and chronicity indices.
GFR performed by EDTA-GFR correctly predicted renal involvement in SLE patients, whereas GFR calculated by the Cockcroft-Gault formula may have underestimated renal function. Significant numbers of patients with WHO class III, IV or V lupus nephritis may be missed if biochemical creatinine clearance or serum creatinine concentration alone is used to assess renal disease.
研究乙二胺四乙酸（EDTA）肾小球滤过率（GFR）是否比血清肌酐浓度或通过Cockcroft-Gault公式计算的肌酐清除率更能准确反映肾脏受累程度。
我们前瞻性研究了过去2年中血清肌酐浓度正常或临界（<110微摩尔/升）且伴有尿沉渣异常和/或蛋白尿的所有系统性红斑狼疮（SLE）患者。同时测定EDTA-GFR、血清肌酐浓度、计算的肌酐清除率（Cockcroft-Gault公式）和24小时尿蛋白。对EDTA-GFR值低或蛋白尿显著的患者进行肾活检。
共纳入23例患者，其中22例为女性。患者的平均年龄为31.6±8.2岁。肾活检结果根据世界卫生组织（WHO）分类如下：II类1例；III类6例；IV类10例；V类6例。平均血清肌酐浓度、EDTA-GFR和计算的肌酐清除率分别为79.8±微摩尔/升、74.5毫升/分钟和97毫升/分钟。23例患者中有15例（65.2%）的EDTA-GFR值异常（<80毫升/分钟），而23例患者中有3例（13%）计算的肌酐清除率异常（<80毫升/分钟）（P<0.001）。使用Pearson相关性检验，我们未发现EDTA-GFR或肌酐清除率值与活动指数和慢性指数之和之间存在任何相关性。
EDTA-GFR测定的GFR能正确预测SLE患者的肾脏受累情况，而通过Cockcroft-Gault公式计算的GFR可能低估了肾功能。如果仅使用生化肌酐清除率或血清肌酐浓度来评估肾脏疾病，可能会遗漏大量WHO III、IV或V级狼疮性肾炎患者。
