Rule Andrew D, Larson Timothy S, Bergstralh Erik J, Slezak Jeff M, Jacobsen Steven J, Cosio Fernando G
Mayo Clinic, Rochester, Minnesota 55905, USA.
Ann Intern Med. 2004 Dec 21;141(12):929-37. doi: 10.7326/0003-4819-141-12-200412210-00009.
The National Kidney Foundation has advocated the use of the abbreviated Modification of Diet in Renal Disease (MDRD) equation to estimate glomerular filtration rate (GFR) from serum creatinine measurements in clinical laboratories. However, healthy persons were not included in the development of the MDRD equation.
To assess the accuracy of the MDRD equation in patients with chronic kidney disease compared with healthy persons and to develop a new equation that uses both patients with chronic kidney disease and healthy persons.
Cross-sectional study.
The Mayo Clinic, a tertiary-care medical center.
Consecutive patients (n = 320) who had an iothalamate clearance test specifically for chronic kidney disease evaluation and consecutive healthy persons (n = 580) who had an iothalamate clearance test specifically for kidney donor evaluation.
Serum creatinine levels, GFR, demographic characteristics, and clinical characteristics were abstracted from the medical record.
The MDRD equation underestimated GFR by 6.2% in patients with chronic kidney disease and by 29% in healthy persons. Re-estimated coefficients for serum creatinine and sex were similar to the original MDRD equation in the chronic kidney disease series but not in the healthy series. At the same serum creatinine level, age, and sex, GFR was on average 26% higher in healthy persons than in patients with chronic kidney disease (P < 0.001). A quadratic GFR equation was developed to estimate logarithmic GFR from the following covariates: 1/SCr, 1/SCr2, age, and sex (where SCr = serum creatinine).
The new equation was not developed in a general population sample. Elderly and African-American persons were underrepresented.
The MDRD equation systematically underestimates GFR in healthy persons. A new equation developed with patients who have chronic kidney disease and healthy persons may be a step toward accurately estimating GFR when the diagnosis of chronic kidney disease is unknown.
美国国家肾脏基金会提倡在临床实验室中使用简化的肾脏病饮食改良（MDRD）方程，通过血清肌酐测量值来估算肾小球滤过率（GFR）。然而，健康人群未被纳入MDRD方程的制定过程。
评估与健康人相比，MDRD方程在慢性肾脏病患者中的准确性，并制定一个同时纳入慢性肾脏病患者和健康人的新方程。
横断面研究。
梅奥诊所，一家三级医疗中心。
连续入选的进行碘肽酸盐清除试验以评估慢性肾脏病的患者（n = 320）以及连续入选的进行碘肽酸盐清除试验以评估肾脏供体的健康人（n = 580）。
从病历中提取血清肌酐水平、GFR、人口统计学特征和临床特征。
MDRD方程在慢性肾脏病患者中使GFR低估了6.2%，在健康人中低估了29%。慢性肾脏病组中血清肌酐和性别的重新估计系数与原始MDRD方程相似，但健康组中则不同。在相同的血清肌酐水平、年龄和性别条件下，健康人的GFR平均比慢性肾脏病患者高26%（P < 0.001）。开发了一个二次GFR方程，通过以下协变量来估算对数GFR：1/SCr、1/SCr²、年龄和性别（其中SCr = 血清肌酐）。
新方程并非在一般人群样本中开发。老年人和非裔美国人的代表性不足。
MDRD方程系统性地低估了健康人的GFR。在慢性肾脏病患者和健康人共同参与下开发的新方程，可能是在慢性肾脏病诊断不明时准确估算GFR的一个进步。
