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Serum cystatin C and urinary enzymes as screening markers of renal dysfunction in diabetic patients.
J Nephrol 2005 Sep-Oct; 18(5):559-67JN

Abstract

BACKGROUND

In clinical practice, the assessment and follow-up of early renal dysfunction is important in diabetic nephropathy. Therefore, this study was designed to determine whether the serum cystatin C (Cys C) and activities of some tubular enzymes could be used as screening markers for renal dysfunction in diabetic patients.

METHODS

Serum Cys C levels and urinary activities of N-acetyl-b-D-glucosaminidase (NAG), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) and whole blood glycolyse hemoglobin (HbA1C) were measured in 56 diabetic patients and 20 healthy subjects (controls). The results were compared with serum creatinine (Cr) and creatinine clearance (CCr), which were measured and estimated with the Cockcroft-Gault formula (CCG) and 24-hr urine microalbuminuria (MAU). We examined the influence of albuminuria, HbA1C and CCr levels of patients on the levels of the analyzed parameters. Sensitivity and specificity for the diagnosis of renal impairment were calculated by a receiver operating characteristics (ROC) curve for serum Cys C, Cr and urinary enzymes.

RESULTS

In normoalbuminurics, only serum Cys C levels and urinary NAG activities were found elevated as compared to controls. In addition to the elevation of serum Cys C levels and urinary activities of NAG, urinary ALP and LDH activities were also found elevated in microalbuminurics. Serum Cys C levels and urinary NAG, ALP, LDH activities started to increase above the normal range when CCr declined and while serum Cr was in the normal range in patients with 50<CCr<80 (grade 2 group). Moreover, these parameters in patients with good metabolic control were significantly lower than in patients with poor metabolic control. There was a significant positive correlation between serum Cys C, urinary NAG, LDH, ALP activities and serum Cr levels. However, there was an inverse correlation between serum Cys C, urinary NAG, LDH, ALP and CCr and CCG in diabetic patients. The ROC plot indicated that serum Cys C and urinary NAG and ALP had higher sensitivity than serum Cr and met the criteria for detecting glomerular and tubular dysfunction as screening tests for early diagnosis of diabetic nephropathy.

CONCLUSION

This study demonstrated that measuring serum Cys C levels and urinary NAG, ALP and LDH activities could be useful as screening markers to follow-up glomerular and tubular dysfunction in diabetic patients.

Authors+Show Affiliations

Department of Biochemistry, Medical Faculty, Osmangazi University, Eskişehir--Turkey. suslu@ogu.edu.trNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Validation Study

Language

eng

PubMed ID

16299682

Citation

Uslu, Sema, et al. "Serum Cystatin C and Urinary Enzymes as Screening Markers of Renal Dysfunction in Diabetic Patients." Journal of Nephrology, vol. 18, no. 5, 2005, pp. 559-67.
Uslu S, Efe B, Alataş O, et al. Serum cystatin C and urinary enzymes as screening markers of renal dysfunction in diabetic patients. J Nephrol. 2005;18(5):559-67.
Uslu, S., Efe, B., Alataş, O., Kebapçi, N., Colak, O., Demirüstü, C., & Yörük, A. (2005). Serum cystatin C and urinary enzymes as screening markers of renal dysfunction in diabetic patients. Journal of Nephrology, 18(5), pp. 559-67.
Uslu S, et al. Serum Cystatin C and Urinary Enzymes as Screening Markers of Renal Dysfunction in Diabetic Patients. J Nephrol. 2005;18(5):559-67. PubMed PMID: 16299682.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Serum cystatin C and urinary enzymes as screening markers of renal dysfunction in diabetic patients. AU - Uslu,Sema, AU - Efe,Belgin, AU - Alataş,Ozkan, AU - Kebapçi,Nur, AU - Colak,Omer, AU - Demirüstü,Canan, AU - Yörük,Ayşe, PY - 2005/11/22/pubmed PY - 2006/1/18/medline PY - 2005/11/22/entrez SP - 559 EP - 67 JF - Journal of nephrology JO - J. Nephrol. VL - 18 IS - 5 N2 - BACKGROUND: In clinical practice, the assessment and follow-up of early renal dysfunction is important in diabetic nephropathy. Therefore, this study was designed to determine whether the serum cystatin C (Cys C) and activities of some tubular enzymes could be used as screening markers for renal dysfunction in diabetic patients. METHODS: Serum Cys C levels and urinary activities of N-acetyl-b-D-glucosaminidase (NAG), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) and whole blood glycolyse hemoglobin (HbA1C) were measured in 56 diabetic patients and 20 healthy subjects (controls). The results were compared with serum creatinine (Cr) and creatinine clearance (CCr), which were measured and estimated with the Cockcroft-Gault formula (CCG) and 24-hr urine microalbuminuria (MAU). We examined the influence of albuminuria, HbA1C and CCr levels of patients on the levels of the analyzed parameters. Sensitivity and specificity for the diagnosis of renal impairment were calculated by a receiver operating characteristics (ROC) curve for serum Cys C, Cr and urinary enzymes. RESULTS: In normoalbuminurics, only serum Cys C levels and urinary NAG activities were found elevated as compared to controls. In addition to the elevation of serum Cys C levels and urinary activities of NAG, urinary ALP and LDH activities were also found elevated in microalbuminurics. Serum Cys C levels and urinary NAG, ALP, LDH activities started to increase above the normal range when CCr declined and while serum Cr was in the normal range in patients with 50<CCr<80 (grade 2 group). Moreover, these parameters in patients with good metabolic control were significantly lower than in patients with poor metabolic control. There was a significant positive correlation between serum Cys C, urinary NAG, LDH, ALP activities and serum Cr levels. However, there was an inverse correlation between serum Cys C, urinary NAG, LDH, ALP and CCr and CCG in diabetic patients. The ROC plot indicated that serum Cys C and urinary NAG and ALP had higher sensitivity than serum Cr and met the criteria for detecting glomerular and tubular dysfunction as screening tests for early diagnosis of diabetic nephropathy. CONCLUSION: This study demonstrated that measuring serum Cys C levels and urinary NAG, ALP and LDH activities could be useful as screening markers to follow-up glomerular and tubular dysfunction in diabetic patients. SN - 1121-8428 UR - https://www.unboundmedicine.com/medline/citation/16299682/Serum_cystatin_C_and_urinary_enzymes_as_screening_markers_of_renal_dysfunction_in_diabetic_patients_ L2 - http://ovidsp.ovid.com/ovidweb.cgi?T=JS&amp;PAGE=linkout&amp;SEARCH=16299682.ui DB - PRIME DP - Unbound Medicine ER -