Comparison of cystatin C- and creatinine-based estimation of glomerular filtration rate according to glycaemic status in Type 2 diabetes

Authors


Tae Seo, Sohn, Uijeongbu St Mary’s Hospital, Geumo-dong, Uijeongbu-si, Gyeonggi-do, 480-717, Korea. E-mail: imsts@catholic.ac.kr

Abstract

Diabet. Med. 29, e121–e125 (2012)

Abstract

Aims  The influence of hyperglycaemia on the performance of glomerular filtration rate (GFR) estimating equations remains to be determined. We compared the performance of creatinine-based GFR with cystatin C-based GFR in patients with Type 2 diabetes according to glycaemic status.

Methods  In a cross-sectional study of 210 patients with Type 2 diabetes, we staged glycaemic status by HbA1c tertiles [HbA1c≤ 75 mmol/mol (9.0%) (n = 70), HbA1c 76–95 mmol/mol (9.1–10.8%) (n = 70), HbA1c >95 mmol/mol (10.8%) (n = 70)] and measured GFR. Isotopic GFR was measured using renal dynamic imaging with 99mTc-diethylene-triamine-penta-acetic acid. Estimated GFR (eGFR) was measured using creatinine-based formulae (Cockcroft–Gault-eGFR, the Modification of Diet in Renal Disease equation-eGFR and the Chronic Kidney Disease Epidemiology Collaboration formula-eGFR) and a cystatin C-based formula (cystatin C-eGFR).

Results  The isotopic GFR of all patients was 93.1 ± 34.1 ml min−1 1.73 m−2. All methods for estimating GFR underestimated isotopic GFR [Cockcroft–Gault-eGFR (68.8 ± 38.6 ml min−1 1.73 m−2) (P < 0.05), Modification of Diet in Renal Disease-eGFR (74.8 ± 31.3 ml min−1 1.73 m−2) (P < 0.05), Chronic Kidney Disease Epidemiology Collaboration-eGFR (72.9 ± 26.6 ml min−1 1.73 m−2) (P < 0.05) and cystatin C-eGFR (83.5 ± 33.2 ml min−1 1.73 m−2) (P < 0.05)]. In all patient groups, cystatin C-eGFR was less biased and more accurate than the creatinine-based formulae, especially in the group with HbA1c > 95 mmol/mol (10.8%) where there was no difference between cystatin C-eGFR and isotopic GFR.

Conclusions  Performance of cystatin C-eGFR was superior to creatinine-based GFR in patients with Type 2 diabetes with HbA1c > 95 mmol/mol (10.8%).

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