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Serum cystatin C advantageous compared with serum creatinine in the detection of mild but not severe diabetic nephropathy
Author(s) -
Christensson A. G.,
Grubb A. O.,
Nilsson J.Å.,
Norrgren K.,
Sterner G.,
Sundkvist G.
Publication year - 2004
Publication title -
journal of internal medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.625
H-Index - 160
eISSN - 1365-2796
pISSN - 0954-6820
DOI - 10.1111/j.1365-2796.2004.01414.x
Subject(s) - cystatin c , creatinine , renal function , medicine , urology , nephropathy , diabetic nephropathy , cystatin , endocrinology , diabetes mellitus , gastroenterology
. Objective. To determine whether serum cystatin C is more accurate than serum creatinine in the detection of diabetic nephropathy, also after adjustment for age. Methods. Forty‐one patients with type 1 and 82 patients with type 2 diabetes were evaluated with serum creatinine, serum cystatin C, and 51 Cr‐EDTA clearance (reference method). Cystatin C was measured by a particle‐enhanced turbidimetric method and creatinine by an enzymatic method. Statistical estimations were performed both without and with age adjustment created by z ‐scores for 51 Cr‐EDTA clearance, creatinine, and cystatin C. The cut‐off levels for glomerular filtration rate (GFR) ( 51 Cr‐EDTA clearance) were 60 and 80 mL min −1 1.73 m −2 , respectively, in absolute values and 80, 90 and 95% CIs, respectively, in age‐adjusted values ( z ‐scores). Results. Estimations without age adjustment showed significantly ( P = 0.0132) closer correlation for cystatin C ( r = 0.817) versus 51 Cr‐EDTA clearance as compared with creatinine ( r = 0.678). However, when using age‐adjusted values, the correlation for cystatin C and creatinine, respectively, versus 51 Cr‐EDTA clearance did not differ. When comparing the diagnostic utilities for serum cystatin C versus serum creatinine in manifest renal impairment (GFR < 60 mL min −1 1.73 m −2 or z ‐scores <−1.28 SD), there were no significant differences between the two markers whether age adjusted or not. However, for diagnosing mild nephropathy (GFR < 80 mL min −1 1.73 m −2 or z ‐score −0.84 SD), serum cystatin C is significantly more useful. Conclusions. Serum cystatin C performed better compared with serum creatinine even when measured enzymatically, to detect mild diabetic nephropathy. However, serum creatinine was as efficient as serum cystatin C to detect advanced diabetic nephropathy.