Rapid and accurate estimation of creatinine clearance in the muscle-wasted elderly by computed tomography.
To develop a new method for accurately predicting creatinine clearance (Ccr) in the debilitated elderly without urine collections, the total muscle volume of both thighs (MV thigh), as a new predictive parameter, was calculated using computed tomography in 68 debilitated patients aged 61-92 years. A regression line between 24-hour urinary creatinine excretion and MV thigh was divided by serum creatinine (Scr), and then the following formula was derived: Ccr (ml/min) = 9 x [MV thigh (cm3) - 100]/[1,000 x Scr (mg/dl)] Predicted Ccr by the new method more closely correlated with measured Ccr (r = 0.862) than did predicted Ccr by Cockcroft and Gault's method (the C-G method) (r = 0.727). Statistical analysis of prediction error (= predicted Ccr-measured Ccr) suggested that the new method could provide more accurate and less biased estimations of Ccr than did the C-G method, even in patients with renal insufficiency. By using computed tomography, we have proposed a more accurate method for predicting Ccr of the debilitated elderly than the C-G method, although the new method has inherent disadvantages of radiation exposure and high cost.
Sanaka
M
M
Department of Preventive Medicine, Tokyo Medical and Dental University, Japan.
Takano
K
K
Shimakura
K
K
Koike
Y
Y
Mineshita
S
S
D000368:Aged; D000369:Aged, 80 and over; D003404:Creatinine / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000378:metabolism*; D009133:Muscular Atrophy / Q000000981:diagnostic imaging / Q000378:metabolism*; D011446:Prospective Studies; D012044:Regression Analysis; D014057:Tomography, X-Ray Computed
D003404:Creatinine