Ability of Cystatin C to Detect Changes in Glomerular Filtration Rate After ACE Inhibition in Patients with Uncomplicated Type 1 Diabetes

• Published in: Clinical and experimental hypertension (1993) 2012-01, Vol.34 (8), p.606-611
• Main Authors: Perkins, Bruce A., Sochett, Etienne B., Cherney, David Z.I.
• Format: Article
• Language: English
• Subjects: Adolescent; Angiotensin-Converting Enzyme Inhibitors - therapeutic use; Biomarkers - blood; Child; creatinine; Creatinine - blood; cystatin C; Cystatin C - blood; Diabetes Mellitus, Type 1 - blood; Diabetes Mellitus, Type 1 - diagnosis; Diabetes Mellitus, Type 1 - drug therapy; Diabetes Mellitus, Type 1 - physiopathology; Diabetic Nephropathies - blood; Enalapril - therapeutic use; Female; Glomerular Filtration Rate - drug effects; Humans; hyperfiltration; inulin; Male; Predictive Value of Tests; Sensitivity and Specificity; type 1 diabetes mellitus
• ISSN: 1064-1963; 1525-6006
• DOI: 10.3109/10641963.2012.681732

Although it is known that glomerular filtration rate (GFR) declines in response to angiotensin converting enzyme (ACE) inhibition, recent observations using GFRCYSTATIN C have shown a paradoxical increase calling into question its validity. In this descriptive study, we aimed to reconcile this observation by simultaneously measuring GFRCYSTATIN C, GFRCREATININE, and gold standard GFRINULIN responses to ACE inhibition. Adolescents with type 1 diabetes and hyperfiltration (n = 9, GFRINULIN ≥ 135 mL/min/1.73 m2) or normofiltration (n = 11) were studied during clamped euglycemia at baseline and after 3-week enalapril therapy. In hyperfilterers, the anticipated GFRINULIN decline before and after enalapril was observed (174 ± 29 mL/min/1.73 m2 to 140 ± 26 mL/min/1.73 m2, P = .01). Although GFRCYSTATIN C equations tended to underestimate while GFRCREATININE equations tended to overestimate baseline GFRINULIN in hyperfilterers, both approaches generally reflected declining GFRINULIN responses to enalapril. Normofilterers demonstrated a trend toward rising GFRINULIN in response to enalapril (112 ± 16 mL/min/1.73 m2 to 119 ± 27 mL/min/1.73 m2, P = .35). Although all estimating equations tended to overestimate baseline GFRINULIN, they generally reflected the rising trend in GFRINULIN in response to enalapril in normofilterers. Although GFRINULIN declines in response to enalapril among hyperfilterers, we confirm the previous observation that it demonstrates a trend to rising among normofilterers. These group trends are both reflected by cystatin C- and creatinine-based estimates.