Department of Pharmacy, University of Southern California, Los Angeles, California 90033, USA.
Pharmacotherapy. 2010 Oct;30(10):1004-10. doi: 10.1592/phco.30.10.1004.
To compare the predictive performance of four equations for estimating glomerular filtration rate (GFR) relative to the gold standard measurement, iothalamate clearance, in patients with human immunodeficiency virus (HIV) who have various degrees of kidney function.
Prospective, cross-sectional analysis.
General clinical research center.
Twenty-two adult (mean age 51 yrs) HIV-positive patients with various degrees of stable kidney function and with lean body mass considered normal for a well-nourished person.
Patients were administered a single dose of intravenous iothalamate 456 mg as a rapid infusion over 3 minutes, 1 hour after an oral fluid load of 600 ml of caffeine-free, sugar-free liquids.
Serial blood and urine samples were obtained for determination of measured GFR. Estimated GFR values were calculated by using four equations: the Cockcroft-Gault equation, the simplified Modification of Diet in Renal Disease Study (MDRD) equation, an equation that incorporates serum creatinine and cystatin C concentrations, and an equation incorporating only serum cystatin C concentration. The predictive performance of the equations was determined by comparing the bias, accuracy, and precision of the estimates with the measured values. Body composition was determined by dual-energy x-ray absorptiometry. The four predictive equations underestimated the measured GFR obtained by the iothalamate method, but the differences were not statistically significant. The MDRD equation and the equation that included both serum cystatin C and creatinine concentrations, as well as age, sex, and race, provided the least bias, most precision, and best accuracy in estimating the measured GFR.
The MDRD equation and the equation that included both serum cystatin C and creatinine concentrations appear to provide accurate, precise, and relatively unbiased estimates of GFR in patients with HIV. Larger studies are needed that include patients with muscle wasting and lipodystrophy in order to validate these preliminary observations and the effects of body composition on the predictability of GFR with use of these equations.
比较 4 种估算肾小球滤过率（GFR）的方程在不同肾功能的人类免疫缺陷病毒（HIV）患者中与金标准碘海醇清除率相比的预测性能。
前瞻性、横断面分析。
综合临床研究中心。
22 名成年（平均年龄 51 岁）HIV 阳性患者，肾功能不同程度稳定，且瘦体重被认为是营养良好的正常人。
患者接受单剂量静脉内碘海醇 456mg，在口服 600ml 无咖啡因、无糖液体负荷后 3 分钟内快速输注。
连续采集血样和尿样，以确定实测 GFR。通过使用 4 种方程计算估算的 GFR 值： Cockcroft-Gault 方程、简化的肾脏病饮食改良研究（MDRD）方程、纳入血清肌酐和胱抑素 C 浓度的方程以及仅纳入血清胱抑素 C 浓度的方程。通过比较估计值与实测值的偏差、准确性和精密度来确定方程的预测性能。通过双能 X 射线吸收法测定身体成分。4 种预测方程均低估了碘海醇法测定的实测 GFR，但差异无统计学意义。MDRD 方程和纳入血清胱抑素 C 和肌酐浓度以及年龄、性别和种族的方程在估计实测 GFR 时提供的偏差最小、精度最高、准确性最好。
MDRD 方程和纳入血清胱抑素 C 和肌酐浓度的方程似乎可以为 HIV 患者提供准确、精确且相对无偏差的 GFR 估计值。需要更大的研究来包括肌肉减少症和脂肪营养不良的患者，以验证这些初步观察结果以及身体成分对这些方程预测 GFR 的可预测性的影响。
