NDT Advance Access originally published online on December 19, 2006
Nephrology Dialysis Transplantation 2007 22(3):959-960; doi:10.1093/ndt/gfl723
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Prediction of glomerular filtration rate decline in diabetic subjects with impaired renal function
Email: vincent.rigalleau{at}wanadoo.frFontseré et al. [1] recently questioned the value of the Cockcroft–Gault (CG) formula and the MDRD equation for the long-term monitoring of glomerular filtration rate (GFR) in type 2 diabetic patients. As also reported by Rossing et al. [2], they found that these equations underestimate the GFR decline; however, they concluded that the MDRD prediction could be used in their most advanced patients (CKD stages 2 and 3; baseline isotopic GFR: 71.2 ± 13.9 ml/min/1.73 m2). We tested whether the prediction equations can also be used in diabetic patients with more advanced renal impairment.
We have prospectively followed-up for 2 years 50 diabetic subjects (31, type 2) with impaired renal function (K/DOQI stages 3–5). Their GFR was determined by 51Cr-EDTA clearance, and compared to the CG and MDRD-predicted values by paired t-tests. The subjects were defined as ‘progressors’ if their GFR decline was higher than the mean of the studied group.
The mean initial GFR was 37.9 ± 21.7 ml/min/1.73 m2, similar to the MDRD (38.1 ± 15.9), whereas the CG overestimated GFR (42.4 ± 18.0; P < 0.05). Five subjects died during the follow-up. Their GFR (38.6 ± 21.8) did not differ from the others, but was overestimated by the CG (55.6 ± 12.0; P < 0.05) and the MDRD (44.1 ± 12.1; NS). Twelve subjects started haemodialysis. Their GFR (17.7 ± 8.9) was lower than the others (P < 0.0001), and was overestimated by the CG (26.4 ± 9.5; P < 0.0001) and the MDRD (22.3 ± 11.6; P < 0.05). Thirty-three subjects had a second GFR measurement 2 years later. Their GFR declined by –(7.7 ± 18.0) ml/min/1.73 m2 [–(14 ± 37)%], from 45.1 ± 20.6 to 37.3 ± 21.6 (P < 0.05). The assessment of GFR decline by the CG and the MDRD is shown in Table 1.
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In accordance with Fontseré [1] and Rossing's [2] findings, we found that the GFR decline was underestimated by the predictive equations. The prediction was, however, correlated to the measured loss of renal function, and the underestimation was moderate: most of the subjects were well-classified as progressors or non-progressors according to their predicted GFR, especially with the MDRD. Despite its limitations, we think that the MDRD prediction is an acceptable alternative when the direct measurement of GFR cannot be performed in renally insufficient diabetic patients [3].
Conflict of interest statement. None declared.
1Nutrition-Diabétologie
Hôpital Haut-Lévêque
Avenue de Magellan
33600 Pessac
2Néphrologie Université
de Bordeaux 2 – Victor Segalen
33000 Bordeaux
3Médecine Nucléaire
Hôpital Pellegrin
Place Amélie Raba-Léon
33000 Bordeaux
France
References
- Fontseré N, Salinas I, Bonal J, et al. (2006) Are prediction equations for glomerular filtration rate useful for the long-term monitoring of type 2 diabetic patients? Nephrol Dial Transplant 21:2152–2158.
[Abstract/Free Full Text] - Rossing P, Rossing K, Gaede P, Pedersen O, Parving HH. (2006) Monitoring kidney function in type 2 diabetic patients with incipient and overt diabetic nephropathy. Diabetes Care 29:1024–1030.
[Abstract/Free Full Text] - Rigalleau V, Lasseur C, Perlemoine C, et al. (2005) Estimation of glomerular filtration rate in diabetic subjects, Cockcroft or MDRD formula? Diabetes Care 28:838–843.
[Abstract/Free Full Text]
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