Ability of Cystatin C to detect changes in glomerular filtration rate after ACE inhibition in patients with uncomplicated type 1 diabetes.
Although it is known that glomerular filtration rate (GFR) declines in response to angiotensin converting enzyme (ACE) inhibition, recent observations using GFR(CYSTATIN C) have shown a paradoxical increase calling into question its validity. In this descriptive study, we aimed to reconcile this observation by simultaneously measuring GFR(CYSTATIN C), GFR(CREATININE), and gold standard GFR(INULIN) responses to ACE inhibition. Adolescents with type 1 diabetes and hyperfiltration (n = 9, GFR(INULIN) ≥ 135 mL/min/1.73 m(2)) or normofiltration (n = 11) were studied during clamped euglycemia at baseline and after 3-week enalapril therapy. In hyperfilterers, the anticipated GFR(INULIN) decline before and after enalapril was observed (174 ± 29 mL/min/1.73 m(2) to 140 ± 26 mL/min/1.73 m(2), P = .01). Although GFR(CYSTATIN C) equations tended to underestimate while GFR(CREATININE) equations tended to overestimate baseline GFR(INULIN) in hyperfilterers, both approaches generally reflected declining GFR(INULIN) responses to enalapril. Normofilterers demonstrated a trend toward rising GFR(INULIN) in response to enalapril (112 ± 16 mL/min/1.73 m(2) to 119 ± 27 mL/min/1.73 m(2), P = .35). Although all estimating equations tended to overestimate baseline GFR(INULIN), they generally reflected the rising trend in GFR(INULIN) in response to enalapril in normofilterers. Although GFR(INULIN) 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.
Division of Endocrinology, University Health Network, University of Toronto, Toronto, ON, Canada.
Bruce A
BA
Perkins
Etienne B
EB
Sochett
David Z I
DZ
Cherney
D000293:Adolescent; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D015415:Biomarkers / Q000097:blood; D002648:Child; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology*; D003928:Diabetic Nephropathies / Q000097:blood; D004656:Enalapril / Q000627:therapeutic use*; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
D000806:Angiotensin-Converting Enzyme Inhibitors; D015415:Biomarkers; D055316:Cystatin C; D004656:Enalapril; D003404:Creatinine