EVALUATION OF THE THREE METHODS AVAILABLE FOR THE ESTIMATION OF CREATININE CLEARANCE
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Radhika Krishnaswamy, Soniya Lukose
Volume : 2
Issue : 2
Online ISSN : 2394-6377
Print ISSN : 2394-6369
Article First Page : 83
Article End Page : 88
Background: The Glomerular filtration rate (GFR) is considered to be the most reliable measure of the functional capacity of the kidneys and is it has proved to be the most sensitive and specific marker of changes in overall renal function. The accurate measurement of the GFR is time consuming, expensive, and not practical for routine clinical use.1 Though Inulin clearance is considered to be the gold standard test, it has not been used widely because it time consuming, expensive, requires continuous infusion, and constraining for the patient. 2, 3, 4 Creatinine clearance is most commonly used for the estimation of GFR. The need to collect a urine sample remains a major limitation of the creatinine clearance test.5 Many formulae have been developed to transform serum creatinine so that it may accurately reflect, GFR.6 Variations in creatinine production owing to age and sex related differences in muscle mass have been measured and incorporated into the formulas to improve the GFR.7 In adults, the most commonly used formulae are those derived from the Modification of Diet in Renal Disease (MDRD) and the Cockcroft-Gault (CG), which have not been validated in Indian population. 8 This study was aimed to compare the diagnostic performance of the MDRD Cockcroft-Gault formulae, and Measured Creatinine Clearance in Indian population.
Materials and Methods: In 370 subjects Creatinine Clearance was calculated by Routine Creatinine Clearance test using serum and urine Creatinine and also through MDRD and the Cockcroft-Gault formulae. Subjects were divided into two groups based on the Measured Creatinine Clearance values. Group A consisted of subjects with Measured Creatinine Clearance >60 ml/min. Group B consisted of subjects with Measured Creatinine Clearance <60 ml/min
Statistical analysis: Correlation (Pearsons correlation) between the values of Clearance obtained through the three methods in the above two groups was analyzed using SPSS-16 version.
Group A (Measured Creatinine Clearance >60 ml/min) The Cockcroft-Gault formula showed strong positive correlation (r value 0.756, p value <0.001) with the Measured Creatinine Clearance than the MDRD formula. (r value 0.684,p value <0. 001)
Group B (Measured Creatinine Clearance <60 ml/min) both Cockcroft and MDRD showed weak positive correlation with Measured Creatinine Clearance. Cockcroft ((r value 0.617, p value <0.001) MDRD (r value 0.613, p value <0.001)
Conclusion: The present study shows weak positive correlation between the Measured Creatinine Clearance, MDRD and Cockcroft formulae at Clearance values<60 ml/min and strong positive correlation between Measured Creatinine Clearance and Cockcroft formula at Clearance values >60 ml/min. Since MDRD formula includes age, gender, and race and developed for the western population with chronic renal insufficiency, further research is needed in our population, to establish and incorporate adjustment& Correction factors in the formula, so that it can be used for a wider range of renal function, in our population to give reliable results and therefore can replace the traditional Measured Creatinine Clearance test.
Keywords: eGFR, Modification of Diet in Renal Disease (MDRD), Cockcroft-Gault (CG) Measured Creatinine clearance.