Although creatinine clearance (Ccr) has been measured clinically by a simple method as a preoperative renal function test, Ccr is not strictly equal to glomerular filtration rate (GFR). Recently, an equation for estimated GFR (eGFR) for Japanese individuals has been postulated, and eGFR has been accepted as equal to measured GFR in chronic kidney disease. However, there have been no previous studies regarding the reliability of eGFR as a preoperative renal function test.
A research article to be published on May 14, 2009 in the World Journal of Gastroenterology
addresses this question. The research team led by Dr. Tokihiko Sawada from Dokkyo Medical University, Japan retrospectively calculated the preoperative three-variable and five-variable equations for eGFR, and compared the results with Ccr in patients undergoing hepatectomy.
One hundred and ninety seven patients undergoing hepatectomy between August 2006 and August 2008 were enrolled in this study. Preoperative Ccr, a three-variable equation for eGFR (eGFR3) and a five-variable equation for eGFR (eGFR5) were calculated. Abnormal values were defined as Ccr < 50 mL/min, eGFR3 and eGFR5 < 60 mL/min/1.73 m2.
The maximum increases in the postoperative serum creatinine (post Cr) level and postoperative rate of increase in the serum Cr level (post Cr rate) were compared. There were 37 patients (18.8%) with abnormal Ccr, 31 (15.7%) with abnormal eGFR3, and 40 (20.3%) with abnormal eGFR5.
Although there were no significant differences in the post Cr rate between patients with normal and abnormal Ccr, eGFR3 and eGFR5 values, the post Cr level was significantly higher in patients with eGFR3 and eGFR5 abnormality than in normal patients (P < 0.0001). Post Cr level tended to be higher in patients with Ccr abnormality (P = 0.0936 and P = 0.0875, respectively).
They concluded that eGFR5 and the simpler eGFR3, rather than Ccr, are recommended as a first-choice preoperative renal function test in patients undergoing hepatectomy.