Accessible Unlicensed Requires Authentication Published by De Gruyter June 1, 2005

Biological Variability of Albumin Excretion Rate and Albumin-to-Creatinine Ratio in Hypertensive Type 2 Diabetic Patients

Andrea Mosca, Renata Paleari, Ferruccio Ceriotti, Annunziata Lapolla and Domenico Fedele
From the journal

Abstract

The importance of measuring microalbuminuria is well established. However, only scanty data are available concerning the biological variability of albumin excretion in type 2 diabetic subjects. We report our experience from a large clinical trial of a new antihypertensive drug (Lercanidipine) designed to reduce albumin excretion and blood pressure in type 2 diabetic patients with hypertension and microalbuminuria.

Eighty seven patients with persistent microalbuminuria were studied within 1 year of the clinical trial. The measurements were performed on blood and timed urine samples frozen at −80 °C and shipped to a central laboratory unit. Preliminary experiments were performed to assess albumin stability in urine under various conditions (4 °C, −20 °C and −80 °C), particularly with regard to the albumin/creatinine ratio. Urine samples can be stored up to 3 weeks at 4 °C or up to 2 months at −80 °C. The biological variability of the albumin excretion rate was 25.7%, while that of the albumin/creatinine ratio was 13.4%. These data are useful in defining the analytical goals of imprecision for microalbuminuria (CV = 13% for albumin, and CV = 6% for albumin/creatinine ratio). No correlation between albumin/creatinine ratio and HbA1c was found in the cohort of 61 microalbuminuric patients who completed the trial.

The results of this study confirm that the albumin/creatinine ratio is much more suitable for monitoring albumin excretion in longitudinal studies than the albumin excretion rate.

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Published Online: 2005-06-01
Published in Print: 2003-09-16

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