Validation of the Virga GFR Equation in a Renal Transplant Population

Zahran, Ahmed; Hossain, Mohammad A.; Kora, Mahmoud A; Galal, Ali Z; Shoker, Ahmed

doi:10.1159/000145457

Cited by 6 publications

(5 citation statements)

References 26 publications

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“…In our study, this equation estimated the highest GFR levels among creatinine-based equations and the lowest CKD prevalence among all equations, particularly in individuals aged ≥65 years. Similar findings have been previously reported when comparing the Virga and MDRD-4 formulae in adult renal transplant recipients [27]. In our study, the Virga equation showed very poor agreement with all other equations.…”

Section: Discussionsupporting

confidence: 84%

Estimating the Glomerular Filtration Rate in the General Population Using Different Equations: Effects on Classification and Association

Pattaro

Riegler

Stifter³

et al. 2013

Nephron Clin Pract

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Background/Aims: Several formulas for glomerular filtration rate (GFR) estimation, based on serum creatinine or cystatin C, have been proposed. We assessed the impact of some of these equations on estimated GFR (eGFR) and chronic kidney disease (CKD) prevalence, and on the association with cardiovascular risk factors, in a general population sample characterized by a young mean age. Methods: We studied 1,199 individuals from three Alpine villages enrolled into the MICROS study. eGFR was obtained with the 4- and 6-parameter MDRD study equations, the Virga equation, and with the three CKD-EPI formulas for creatinine, cystatin C, and the combination of creatinine and cystatin C. We assessed the concordance between quantitative eGFR levels, CKD prevalence, and in terms of association with total, LDL, and HDL cholesterol. Results: The highest and lowest eGFR levels corresponded to the cystatin C-based and MDRD-4 equations, respectively. CKD prevalence varied from 1.8% (Virga) to 5.8% (MDRD-4). The CKD-EPI based on creatinine showed the highest agreement with all other equations. Agreement between methods was higher at lower eGFR levels, older age, and in the presence of diabetes and hypertension. Creatinine-based estimates of eGFR were associated with total and low-density lipoprotein but not high-density lipoprotein cholesterol. The opposite was observed for the cystatin C-based GFR. Conclusion: GFR estimation is strongly affected by the chosen equation. Differences are more pronounced in healthy and younger individuals. To identify CKD risk factors, the choice of the equation is of secondary importance to the choice of the biomarker used in the formula. If eGFR is not calibrated to a gold standard GFR in the general population, reports about CKD prevalence should be considered with caution.

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Section: Discussionsupporting

confidence: 84%

Estimating the Glomerular Filtration Rate in the General Population Using Different Equations: Effects on Classification and Association

Pattaro

Riegler

Stifter³

et al. 2013

Nephron Clin Pract

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“…In this regard, the results are consistent with our previous work. 16,20 For example, the IDMS demonstrated significantly negative bias in those with minimal renal dysfunction and improved bias especially with those with moderate to severe renal dysfunction, consistent with the literature of all eGFR equation and estimated iGFR. 13,21 Similarly, accuracy of IDMS and precision were significantly lower in patients with minimal renal dysfunction while the CKD-EPI was better particularly in those with minimal renal dysfunction.…”

Section: Discussionsupporting

confidence: 80%

The Practical Implications of Using Estimated GFR as the Presumed Reference Variable to Estimate Transplant Chronic Kidney Disease

Elmoselhi

Hossain

Khamis

et al. 2011

Nephrology Research & Reviews

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We determined the proportions of matched kidney transplant isotope GFRs (iGFRs) to the estimated functions (eGFRs) calculated from Isotope Dilution Mass Spectrometry (IDMS), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and Cockcroft-Gault (CG) equations. Method: 1403 iGFR/eGFR pairs on 390 kidney transplant patients were compared considering the iGFR or eGFR as the reference or test variable. Results: Conformity of iGFR to CG estimates demonstrated the least bias of 1.3±18.4 mL/ min/1.73 m2 (compared to 1.5±19.4 and -2.2±19.2 for IDMS and CKDI-EPI, P<.05) and CKD-EPI estimates the highest precision of 4.1±41.8 (compared to 11.3±43.9 for IDMS and 5.7±37.3 for CG; P<.05). IDMS eGFR cut-off <60 and <30 mL/min/1.73m2 were correctly matched by iGFR in 79.4% and 49.1% of the times, while CKD-EPI was matched by iGFR in 83.5% and 52.5%. CG was matched in 78.3% and 53.6%. IGFR cut-off levels of <60, and <30 mL/min/1.73m2 were predicted by IDMS in 83.8 % and 64.0% of the times. CKD-EPI was correct in 77.8% and 59.0% and CG in 82.5% and 41.6% respectively. Conclusion: Transplant eGFR results obtained by CKD-EPI or CG are likely to be more precise and less biased than IDMS

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“…When more than one CR was done, the lowest value was used, to avoid CR results possibly associated with acute renal impairment. Estimated glomerular ltration rates (eGFR's) were calculated in the original Modi cation of Diet in Renal Disease Study Group (MDRD) equation that uses age, sex, CR, black/ white ethnicity [17]. We did not adjust for ethnicity because Saskatchewan has only a small black population and the unadjusted eGFR equation has been preliminarily validated in a North American Indian population [18].…”

Section: Methodsmentioning

confidence: 99%

Differences in glycemic control and survival predict higher ESRD rates in diabetic first nations adults

Dyck¹,

Sidhu²,

Klomp³

et al. 2010

CIM

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Di erences in glycemic control and survival predict higher ESRD rates in diabetic rst nations adults Abstract Purpose: Diabetic First Nations people (FN) have higher ESRD rates than other Canadians but the reasons remain unclear. We sought to better understand this disparity by comparing demographic, laboratory and survival features of diabetic FN and other Saskatchewan residents (OSK) by renal function stage.Methods: Prevalent diabetes cases in 2005/06 were identi ed in Saskatchewan's two largest health regions using administrative databases, and linked with centralized laboratory tests. ey were sub-divided into ve stages of renal function using estimated glomerular ltration rates (eGFR) that were determined in 992 of 2,321 FN (42.7%) and 14,054 of 21,886 OSK (64.2%). Age, sex, urine microalbumin (MA), glycosylated hemoglobin (A1C), low density lipoprotein cholesterol (LDL-C) and two year mortality risk was compared for all subjects.Results: Diabetic FN were younger (mean age 52.7 vs. 64.2, p<0.0001), more likely to be female (59.6% vs.45.4%, p<0.001), had increased MA (56.6% vs. 48.4%, p<0.0001) and displayed higher mean A1C levels (8.16% vs.7.36%, p<0.0001) than OSK. Despite a larger proportion having eGFR's >60 ml/min (87.0% vs.77.3%, p<0.001), FN were also more likely to have ESRD (2.3% vs.0.8%, p<0.001). Although FN with eGFR's >30 ml/min experienced higher age/sex adjusted mortality risk than OSK, the trends for both adjusted and unadjusted mortality risks for those with advanced pre-ESRD renal failure were lower for FN than for OSK.Conclusions: Elevated rates of ESRD experienced by FN with diabetes are related to poorer glycemic control at all levels of renal function, and lower age-related mortality at advanced stages of chronic kidney disease. ORIGINAL RESEARCH © 2010 CIMClin In E390 Diabetes mellitus is the most common cause of end stage renal disease (ESRD) in Canada [1] but the burden of diabetic ESRD upon indigenous peoples is of particular concern. In 1994, a disproportionate incidence of ESRD was reported among Saskatchewan First Nations (FN) people with diabetes [2] and a recent study shows that such disparities persist [3]. While the mechanisms underlying these observations are incompletely understood, there are two possibilities. First, FN with diabetes may be more prone to the initial development of diabetic glomerulosclerosis, which can lead to ESRD. is is supported by reports that diabetic FN have higher rates of microalbuminuria [4]. Second, FN with early diabetic glomerulosclerosis may progress to ESRD more frequently than others because of a more rapid course and/or lower mortality rates. Although our recent ndings that FN are diagnosed at a a younger age and experience a longer duration between diabetes and ESRD diagnoses are consistent with a di erential mortality e ect [5] other studies report lower survival rates among FN with all-cause advanced chronic kidney disease (CKD) [6].Identifying the mechanisms underlying ethnicity-based di erences in diabetic ESRD is important for understa...

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Validation of the Virga GFR Equation in a Renal Transplant Population

Cited by 6 publications

References 26 publications

Estimating the Glomerular Filtration Rate in the General Population Using Different Equations: Effects on Classification and Association

Estimating the Glomerular Filtration Rate in the General Population Using Different Equations: Effects on Classification and Association

The Practical Implications of Using Estimated GFR as the Presumed Reference Variable to Estimate Transplant Chronic Kidney Disease

Differences in glycemic control and survival predict higher ESRD rates in diabetic first nations adults

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