Accounting for Body Composition does not Improve Cystatin C Estimation of GFR in Diabetic Subjects with CKD
2007; Elsevier BV; Volume: 49; Issue: 4 Linguagem: Inglês
10.1053/j.ajkd.2007.01.024
ISSN1523-6838
AutoresVincent Rigalleau, C. Raffaitin, H. Gin, Marie-Christine Beauvieux, F. Le Moigne, Catherine Lasseur, Philippe Chauveau, Christian Combe, Nicole Barthe,
Tópico(s)Diabetes, Cardiovascular Risks, and Lipoproteins
ResumoMacdonald et al1Macdonald J. Marcora S. Jibani M. et al.GFR estimation using cystatin C is not independent of body composition.Am J Kidney Dis. 2006; 48: 712-719Abstract Full Text Full Text PDF PubMed Scopus (138) Google Scholar recently reported that cystatin C (CysC) levels were influenced by lean body mass (LM) in patients with chronic kidney disease and developed glomerular filtration rate (GFR)-predictive equations based on CysC level alone (GFRCysC) or associated with LM (GFRLM) or demographic variables (GFRdemo). We compared them with isotopic GFRs in 41 patients with diabetes (31 men; 31 patients with type 2 diabetes; age, 65 ± 12 years; body mass index, 26.0 ± 4.6 kg/m2Macisaac R.J. Tsalamandris C. Thomas M.C. et al.Estimating glomerular filtration rate in diabetes: A comparison of cystatin-C and creatinine-based methods.Diabetologia. 2006; 49: 1686-1689Crossref PubMed Scopus (128) Google Scholar). We measured LM (dual-energy X-ray absorptiometry) and CysC (immunonephelometry; N-Latex Cystatin C; Dade Behring, Marburg, Germany). CysC level was 1.81 ± 0.62 mg/L and correlated with GFR (r = 0.80; P < 0.001), but not LM (r = 0.04). Serum creatinine (SCr) level (Jaffé method) was 165 ± 55 μmol/L, correlated with GFR (r = 0.68; P < 0.001), and almost correlated with LM (r = 0.25; P = 0.08). Table 1 shows the comparison between equations.Table 1Comparison Between the Cystatin-C Derived Estimations of GFR, the Abbreviated MDRD Estimation, and Isotopic GFR (mL/min)Included VariablesGFR⁎Mean ± SD. (mL/min)Correlation With GFR (r)Difference From Isotopic GFRAccuracy Within 30% Error (%)51Cr-EDTA–determined GFR: 39.3 ± 18.4GFRCysCCysC45.2 ± 19.20.85+5.9, P < 0.00168.3GFRLMCysC, LM50.3 ± 21.90.63+11.0, P < 0.00153.7GFRdemoCysC, body weight, sex44.4 ± 19.30.59+5.1, P = 0.0648.8MDRD equationSCr, age, sex, race39.4 ± 13.20.84+0.1, not significant65.9Note: To convert GFR in mL/min to mL/s, multiply by 0.01667.Abbreviation: MDRD, Modification of Diet in Renal Disease; 51Cr, chromium 51. Mean ± SD. Open table in a new tab Note: To convert GFR in mL/min to mL/s, multiply by 0.01667. Abbreviation: MDRD, Modification of Diet in Renal Disease; 51Cr, chromium 51. CysC remains a promising marker, correlated better with GFR than SCr level.2Macisaac R.J. Tsalamandris C. Thomas M.C. et al.Estimating glomerular filtration rate in diabetes: A comparison of cystatin-C and creatinine-based methods.Diabetologia. 2006; 49: 1686-1689Crossref PubMed Scopus (128) Google Scholar The simple GFRCysC correlated with GFR and the Modification of Diet in Renal Disease equation, performing well although SCr levels were not recalibrated to the Modification of Diet in Renal Disease laboratory. CysC level did not depend on LM; therefore, equations developed by Macdonald et al1Macdonald J. Marcora S. Jibani M. et al.GFR estimation using cystatin C is not independent of body composition.Am J Kidney Dis. 2006; 48: 712-719Abstract Full Text Full Text PDF PubMed Scopus (138) Google Scholar were poorly predictive of GFR. Some diabetes-specific bias, such as the influence of glucose control,3Rigalleau V. Lasseur C. Raffaitin C. et al.Glucose control influences glomerular filtration rate and its prediction in diabetic subjects.Diabetes Care. 2006; 29: 1491-1495Crossref PubMed Scopus (41) Google Scholar may explain this result. Dual-energy X-ray absorptiometry–determined LM also may not reflect body cell mass well because hydration status changes with chronic kidney disease.4Raffaitin C. Lasseur C. Chauveau P. et al.Nutritional status in patients with diabetes and chronic kidney disease: A prospective study.Am J Clin Nutr. 2007; 85: 96-101PubMed Google Scholar Letters to the Editor may be in response to an article that appeared in AJKD no more than 6 months previously, or may concern a topic of interest to current nephrology. The body of the letter should be as concise as possible and in general should not exceed 250 words. Up to 10 references and 1 figure or table may be included. There is no guarantee that letters will be published. Letters are subject to editing and abridgment without notice.Letters should be submitted via AJKD’s online manuscript handling site, www.editorialmanager.com/ajkd. More information, including details about how to contact the editorial staff for assistance, is available in the journal’s Information for Authors. Letters to the Editor may be in response to an article that appeared in AJKD no more than 6 months previously, or may concern a topic of interest to current nephrology. The body of the letter should be as concise as possible and in general should not exceed 250 words. Up to 10 references and 1 figure or table may be included. There is no guarantee that letters will be published. Letters are subject to editing and abridgment without notice. Letters should be submitted via AJKD’s online manuscript handling site, www.editorialmanager.com/ajkd. More information, including details about how to contact the editorial staff for assistance, is available in the journal’s Information for Authors. In ReplyAmerican Journal of Kidney DiseasesVol. 49Issue 4PreviewWe thank Rigalleau et al for their interest in our report and are encouraged that other researchers have begun applying our methods. As originally stated, our intention is to test the hypothesis that glomerular filtration rate (GFR) estimation using cystatin C (CysC) level is not independent of body composition, not to generate estimation equations for use in clinical practice. Consequently, it is not surprising that our equations, developed in 77 patients, perform poorly against the Modification of Diet in Renal Disease equation. Full-Text PDF GFR Estimation Using Cystatin C Is Not Independent of Body CompositionAmerican Journal of Kidney DiseasesVol. 48Issue 5PreviewBackground: Cystatin C (CysC) is an endogenous marker of glomerular filtration rate (GFR) that is claimed to be unaffected by body composition. In this study, we tested this speculation. Methods: In 77 patients with chronic kidney disease (mean age, 65.1 ± 11.9 [SD] years; mean indexed GFR, 45.7 ± 28.6 mL/min/1.73 m2 [0.76 ± 0.48 mL/s]), we evaluated kidney function (GFR) by means of inulin clearance. CysC level was determined by using a particle-enhanced turbidimetric immunoassay. Total lean (LM) and fat masses were measured by means of dual-energy x-ray absorptiometry. Full-Text PDF
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