Purpose of our survey was to happen out correlativity between estimated Glomerular Filtration Rate ( eGFR ) by Modification of Diet in Renal Disease ( MDRD ) expression and eGFR by Cockcroft-Gault ( CG ) equations, in patients with chronic kidney disease ( CKD ) , and to see whether they can be used interchangeably.
We conducted a cross subdivision survey of 70 patients presented to the nephrology clinic over a period of one twelvemonth. We compared the eGFR by these two expressions in five phases of CKD. Abbreviated 4 variable MDRD expression was used.
MDRD consequences were expressed in ml/min/1.73m2 and CG consequences in ml/min. Age scope was 15 – 79 old ages ; Male 49 % , Female 51 % . The correlativity ( R ) between eGFR by MDRD and eGFR by CG for CKD stages 1 to 5 was 0.64 ; 0.31 ; 0.32 ; 0.67 ; and 0.45 severally. The correlativity ( R ) between creatinine clearance by 24 hr urine aggregation to eGFR by MDRD expression was 0.84 ( P: 0.001 ) and to eGFR by CG expression was and 0.79 ( P: 0.001 ) .
We conclude that Cockcroft-Gault ( CG ) equation correlates best with MDRD expression at CKD phase 4 followed by phase one. Cockcroft-Gault expression underestimated eGFR in phases 1, 2 and 3. We speculate that standardization of Cockcroft-Gault equation to the organic structure surface country of.73m2 will farther better the correlativity but will diminish its utility on bed side. . There is a demand of a big graduated table population based survey to formalize our consequences.
MDRD, Cockcroft-Gault, Chronic kidney disease
Alteration of Diet in Renal Disease ( MDRD ) and Cockcroft-Gault ( CG ) equations are the most common methods of appraisal of Glomerular Filtration Rate ( GFR ) . Both formulas depend upon serum Creatinine to gauge GFR. Creatinine clearance measuring utilizing 24 hours urine aggregation is mostly abandoned in favour of the MDRD and CG expressions. It is chiefly because of the familial troubles in accurate aggregation of 24 hours urine.
Cockcroft-Gault expression remained the most common method of bedside appraisal of GFR. It requires weight in add-on to age but still is really easy to utilize without a reckoner or computing machine.
This advantage of CG expression is maintaining it alive in spite the of rapid popularity of MDRD expression. Numerous surveies are done to compare these two equations in assorted scenes. However the information from Asia particularly from Pakistan is bare [ 1 ] .
Purpose of our survey was to happen out correlativity between the two equations in patients with chronic kidney disease ( CKD ) and to see whether they can be used interchangeably.
We conducted a cross subdivision survey of 70 patients presented to the nephrology clinic of a third attention infirmary in Karachi Pakistan over a period of 1 twelvemonth from January 2006 to December 2006. Aim of our survey was to happen out correlativity between estimated Glomerular Filtration Rate ( eGFR ) by Modification of Diet in Renal Disease ( MDRD ) and eGFR by Cockcroft-Gault ( CG ) equations in patients with chronic kidney disease ( CKD ) and to see whether they can be used interchangeably.
Age scope was 15 – 79 old ages. Male were 49 % , female were 51 % . Patients with acute nephritic failure were excluded. All the patients in the survey were divided into five groups harmonizing to the kidney disease outcome quality enterprise ( KDOQI ) categorization of chronic kidney disease as follows: Group 1: GFR & gt ; 90 ; Group 2: GFR 90 – 60 ; Group 3: GFR 30 – 59 ; Group 4: GFR 15 – 29 and group 5: GFR & lt ; 15 ml/ min/1.73m2.
Abbreviated four variable MDRD expression was used.to estimated GFR ( ml/min per 1.73 M2 ) utilizing the equation:186 x [ serum creatinine ( mg/dl ) ] -1.154 x ( age ) -0.203 x ( 0.742 if female ) . Estimated GFR utilizing the CG equation ml/min ) was calculated as follows: ( 140 – age ) ten ( weight in kilogram ) /serum creatinine ( mg/dl ) x 72 ten ( 0.85 if female ) . Measured creatinine clearance was calculated by 24 hr urine aggregation and utilizing the expression: creatinine elimination ( mg/kg per twenty-four hours ) divided by serum creatinine ( mg/dl ) divided by 14.4 ( min/d per dl/ml ) . Data was analyzed utilizing SPSS package.
MDRD consequences were expressed in ml/min/1.73m2 and CG consequences in ml/min. Mean GFR by MDRD expression for CKD stages 1 to 5 was 111A±30, 77A±24, 39A±9, 21A±6 and 13A±4 severally. Mean GFR by Cockcroft-Gault equation for CKD phase 1 to 5 was 119A±28, 78A±13, 43A±7, 23A±3 and 12A±2 severally ( table 1 ) . The correlativity coefficient ( R ) between eGFR by MDRD and eGFR by Cockcroft-Gault for CKD phases 1-5 was 0.64 ; 0.31 ; 0.32 ; 0.67 ; and 0.45 severally ( table 2 ) .
Mean and average eGFR by MDRD was 48A±40 and 32 ( 58-7 ) severally for all patients. Mean and average eGFR by Cockcroft-Gault was 52A±42 and 36 ( 197-7 ) severally for all patients ( table 3 ) .
The Cockcroft-Gault equation correlated best with MDRD expression at CKD phase four followed by the phase one. The eGFR by MDRD was lesser as comparison to by CG, in phases 1, 2 and 3.
The creatinine clearance by 24 urine aggregation was correlated to the eGFR by MDRD expression. The R value was 0.84 with p value of 0.001. Similarly the creatinine clearance by 24 urine aggregation was correlated to the eGFR by CG expression. The R value was 0.79 with p value of 0.001. ( Table 4 )
Accurate measuring of GFR in chronic kidney disease can non be overemphasized. It is particularly of import when GFR reaches near phase 3 and 4. The of import determination like doing AV fistulous withers and induction of nephritic replacing therapy are taken at this clip.
There were more than eight expressions introduced to gauge GFR but merely two viz. Cockcroft-Gault ( CG ) and MDRD got the credence by the medical community. The CG Formula was proposed every bit early as 1976 [ 2 ] . Because of its simpleness and bedside usage, it was readily accepted by the doctors. The CG expression enjoyed this monopoly till the MDRD equation was introduced in 1999 [ 3 ] .
Twenty four hr urine aggregation for Creatinine clearance measuring is non method of pick because of several booby traps. The most of import being the 24 hr urine aggregation is frequently non accurate. In add-on the serum creatinine remains within normal scope in early phases of CKD due to increased cannular secernment ensuing in overestimate of GFR.
Using Inulin clearance to mensurate GFR is really cumbrous and non practical for everyday clinical pattern. Alternatively, the radioactive and non-radioactive based markers e.g. Iothalamate, Iohexol, DTPA and EDTA are used. The isotope based GFR measurings are thought to be the most accurate but they are dearly-won and non available in many research labs. Therefore their public-service corporation is confined practically to research. They are used as a gilded criterion to formalize the truth of eGFR by MDRD or CG equations. In our survey we still used the traditional 24 hr urine aggregation to cipher creatinine clearance. We were really peculiar and thorough in giving the direction to the patients. The strong correlativity of 24 hr creatinine clearance to eGFR by CG every bit good as MDRD expression goes in favour of our premise that urine aggregation was accurate.
MDRD survey equation originally required six variables viz. Serum Creatinine, Serum Albumin, Serum Urea Nitrogen, Gender, Age and Race. Later a simpler four variable equation was proposed and is considered to be a good as six variable equation [ 3 ] . This brief MDRD equation requires Serum Creatinine, Age, Gender and Race merely. It does non necessitate Serum Albumin and Serum Urea Nitrogen. The usage of standardised serum creatinine in re-expressed 4 variable MDRD expression improves the truth [ 4, 5 ] . Surveies have shown that accommodation for organic structure surface country improves the truth of Cockcroft-Gault expression [ 6,7 ] . The demand of this simpler four variable MDRD equation raised due to trouble of utilizing 6 variable equation on bedside. However still its chief drawback remains the demand of a computing machine.
There are a figure of surveies comparing the MDRD to CG expression with variable consequences. Following is the reappraisal of some of import surveies.
MDRD equation provides indifferent and moderately accurate estimations across broad scope of subgroups when GFR is less than 60 ( CKD Stage 3, 4 & A ; 5 ) [ 8 ] . They besides proved to be dependable for followup in CKD patients in longitudinal surveies [ 9 ] .
MDRD equation performed better than CG equation in CKD, when GFR was less than 60 ml/min/ 1.73 M2. On the other manus CG equation performed better in healthy kidney givers [ 10 ] . CG expression was less precise than MDRD equation in most instances with average GFR of 59.8 ml/ min/ 1.73 M2s [ 11 ] .
In another survey appraisal of GFR in older patients with CKD and average GFR of 53 ml/ min/ 1.73 m2. , the CG Formula was more precise than MDR Formula [ 12 ] . In diabetic patients MDRD every bit good as CG expression correlated good with isotopic GFR measurings, but MDRD equation turned-out to be more accurate [ 13 ] .
In ill hospitalized patients the public presentation of MDRD and CG equation was compared, utilizing Iodine iothalamate as a control. MDRD equation performed better [ 14 ] . MDRD Formula as comparison to CG expression underestimates GFR in healthy persons [ 15 ] .
MDRD expression was more accurate than CG expression in ESRD patients. However MDRD expression underestimated GFR when inulin clearance was more than 8 ml/min/1.73 M2 and overestimated GFR when inulin clearance was less than 8 ml/min/1.73 M2. On the other manus CG expression overestimated GFR when inulin clearance was less than 13 ml/mim/11.73 M2. [ 16 ] .
In patients with CKD but normal serum creatinine, CG Formula was found to be more accurate than MDRD Formula. Measurement of GFR by endogenous and exogenic filtration markers might be the most prudent scheme [ 17 ] .
We conclude that CG Formula correlates with MDRD equation best at CKD stages 4 and overestimated GFR at phases 1, 2, 3. The two expressions may be used interchangeably at phase 4 & A ; 1. Measurement of 24 hr urine creatinine clearance may still be dependable if patients are counseled decently.
Standardization of GFR for organic structure surface country of 1.73 m2.improves the truth of Cockcroft Gualt expression. We speculate that this in bend will better its correlativity with MDRD expression. However we suspect that perplexing the Cockcroft Gualt expression by including the organic structure surface country in equation will diminish its utility on bed side.
It is improbable that MDRD expression will replace Cockcroft Gualt expression in clinical medical pattern shortly because of its dependence upon a computing machine plan.