Early renal failure detection by cystatin C in Type 2 diabetes mellitus: varying patterns of renal analyte expression

Abstract

The early stages of renal failure are poorly diagnosed by current routine tests. We studied cystatin C and routine renal analyte patterns in Type 2 diabetes mellitus. Type 2 diabetes mellitus patients (n = 48) were tested for serum cystatin C, urine albumin, haemoglobin A1c, serum creatinine, serum urea, urine creatinine, glucose, triglycerides and low density lipoproteins (LDL). Glomerular filtration rate (GFR) estimates were made using Cockroft-Gault and Modification of Diet in Renal Disease formulae. The cystatin C (95%CI) reference range was 0.78-0.86 mg/L. While serum cystatin C showed general correlation with routine renal tests, a plateau was observed in analytes measured against cystatin C. Cystatin C improved sensitivity led to detection of renal abnormality in 19% of patients not diagnosed by routine tests. Cystatin C is a more sensitive marker of renal disease in Type 2 diabetes mellitus where estimated GFR is unreported at >60 mL/min and where antihypertensive medications render microalbuminuria detection unreliable. Its incorporation into a panel of renal function tests is highly recommended.