Background Guidelines recommend estimation of glomerular filtration rate (eGFR) prior to iodine contrast media (CM) examinations. It is also recommended that absolute eGFR in mL/min, not commonly used relative GFR (adjusted to body surface area; mL/min/1.73?m(2)), should be preferred when dosing and evaluating toxicity of renally excreted drugs. Purpose To validate the absolute Lund-Malmö equation (LM-ABS) in comparison with the absolute Cockcroft-Gault (CG) equation and the relative equations, revised Lund-Malmö (LM-REV), MDRD, and CKD-EPI, after converting relative estimates to absolute values, and to analyze change in eGFR classification when absolute instead of relative eGFR was used. Material and Methods A total of 3495 plasma clearance of iohexol to measure GFR (mGFR) served as reference test. Bias, precision, and accuracy (percentage of estimates ±30% of mGFR; P30) were compared overall and after stratification for various mGFR, eGFR, age, and BMI subgroups. Results The overall P30 results of CG/LM-ABS/LM-REV/MDRD/CKD-EPI were 62.8%/84.9%/83.7%/75.3%/75.6%, respectively. LM-ABS was the most stable equations across subgroups and the only equation that did not exhibit marked overestimation in underweight patients. For patients with relative eGFR 30-44 and 45-59?mL/min/1.73?m(2), 36% and 58% of men, respectively, and 24% and 32% of women, respectively, will have absolute eGFR values outside these relative eGFR intervals. Conclusion Choosing one equation to estimate GFR prior to contrast medium examinations, LM-ABS may be preferable. Unless absolute instead of relative eGFR are used, systematic inaccuracies in assessment of renal function may occur in daily routine and research on CM nephrotoxicity may be flawed.
Decentralized glomerular filtration rate (GFR) estimates in healthy kidney donors show poor correlation and demonstrate the need for improvement in quality and standardization of GFR measurements in Sweden.
OBJECTIVE: Glomerular filtration rate (GFR) is generally accepted as the best overall index of renal function. Thus, all potential live kidney donors are tested to ensure that they have a normal GFR before they are eligible for kidney transplantation. The choice of GFR test is very much dependent on local traditions and may include iohexol, 51Cr-EDTA, inulin, or creatinine clearance based on urine collection, and creatinine clearance calculated from the Cockcroft-Gault or Modification of Diet in Renal Disease (MDRD) equation as well as cystatin C. The aim of this study was to compare the results of GFR measurements performed in all actual live kidney donors who have undergone live donor nephrectomy at the University Hospital in Uppsala, Sweden, between the years 2000 and 2004. MATERIAL AND METHODS: The patients were selected from all parts of Sweden and the measurements were performed at their local hospital. RESULTS: We found large discrepancies between repeated iohexol measurements in these presumably healthy individuals. There was also a poor correlation between iohexol clearance and calculated creatinine clearance using the Cockcroft-Gault (R2=0.046) or MDRD formula (R2=0.045). CONCLUSIONS: The study shows that the standardization and quality of GFR measurements in Sweden have to be improved.
Differences in body composition may lead to imprecision in estimates of glomerular filtration rate (eGFR) derived from serum creatinine. Our aims were to examine the relationship between eGFR and anthropometric and body composition measures and handgrip strength.
We analyzed data from a cross-sectional study comprising 1,630 randomly selected community-dwelling adults. The Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations were used to calculate eGFR from IMDS-standardized serum creatinine. Body mass index and body surface area were calculated from measured height and weight. Body composition was determined by dual-energy x-ray absorptiometry, handgrip strength measured by a hand-held dynamometer. Regression analysis was used to examine the association between eGFR and other factors.
In women, eGFR determined by the MDRD equation was inversely associated with height (ß = -0.08; p = 0.012), lean mass percentage (ß = -0.06; p = 0.047) and handgrip strength (ß = -0.15; p