Scappaticci Gianni B, Regal Randolph E
Gianni B Scappaticci, Department of Pharmacy Services, University of Michigan Health System and College of Pharmacy, Ann Arbor, MI 48109-2054, United States.
World J Hepatol. 2017 Jan 28;9(3):131-138. doi: 10.4254/wjh.v9.i3.131.
The Cockcroft-Gault (CG) equation has become perhaps the most popular practical approach for estimating renal function among health care professionals. Despite its widespread use, clinicians often overlook not only the limitations of the original serum creatinine (SCr) based equation, but also may not appreciate the validity of the many variations used to compensate for these limitations. For cirrhotic patients in particular, the underlying pathophysiology of the disease contributes to a falsely low SCr, thereby overestimating renal function with use of the CG equation in this population. We reviewed the original CG trial from 1976 along with data surrounding clinician specific alterations to the CG equation that followed through time. These alterations included different formulas for body weight in obese patients and the "rounding up" approach in patients with low SCr. Additionally, we described the pathophysiology and hemodynamic changes that occur in cirrhosis; and reviewed several studies that attempted to estimate renal function in this population. The evidence we reviewed regarding the most accurate manipulation of the original CG equation to estimate creatinine clearance (CrCl) was inconclusive. Unfortunately, the homogeneity of the patient population in the original CG trial limited its external validity. Elimination of body weight in the CG equation actually produced the estimate closest to the measure CrCl. Furthermore, "rounding up" of SCr values often underestimated CrCl. This approach could lead to suboptimal dosing of drug therapies in patients with low SCr. In cirrhotic patients, utilization of SCr based methods overestimated true renal function by about 50% in the literature we reviewed.
Cockcroft-Gault（CG）方程或许已成为医疗保健专业人员中估算肾功能最常用的实用方法。尽管其应用广泛，但临床医生往往不仅忽视了基于血清肌酐（SCr）的原始方程的局限性，而且可能并未认识到用于弥补这些局限性的众多变体的有效性。特别是对于肝硬化患者，该疾病的潜在病理生理学导致SCr假性降低，从而在该人群中使用CG方程时高估了肾功能。我们回顾了1976年的原始CG试验以及随时间推移围绕临床医生对CG方程的特定改动的数据。这些改动包括肥胖患者体重的不同计算公式以及SCr较低患者的“向上取整”方法。此外，我们描述了肝硬化中发生的病理生理学和血流动力学变化；并回顾了几项试图估算该人群肾功能的研究。我们所回顾的关于对原始CG方程进行最准确操作以估算肌酐清除率（CrCl）的证据尚无定论。不幸的是，原始CG试验中患者群体的同质性限制了其外部有效性。在CG方程中去除体重实际上得出了最接近测量的CrCl的估算值。此外，SCr值的“向上取整”往往会低估CrCl。这种方法可能导致SCr较低患者的药物治疗剂量欠佳。在我们所回顾的文献中，肝硬化患者使用基于SCr的方法高估真实肾功能约50%。
