Comparison of urinary albumin-creatinine ratio and albumin excretion rate in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study.
OBJECTIVE
The objective of this study was to compare random urine albumin-creatinine ratio (ACR) with timed urine albumin excretion rate (AER) in patients with type 1 diabetes.


METHODS
A total of 1186 participants in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Study provided spot urine specimens concurrent with 4-hour timed urine collections. ACR and AER were compared using Bland-Altman plots, cross-classification of albuminuria status and its change over time, and within-person variability.


RESULTS
Despite moderate correlation (r=0.62), ACR levels (mg/g) were lower than AER levels (mg/24 hr). This difference was greatest for men. Gender-specific estimated AER (eAER) values were empirically derived from ACR. Comparing the eAER with measured AER, agreement of prevalent microalbuminuria and macroalbuminuria classification was fair to moderate, and classification of change in albuminuria status over time was different. Intraclass correlations were 0.697 for ACR and 0.803 for AER. Effects of DCCT intensive versus conventional diabetes therapy on urine albumin excretion or classification of albuminuria were similar using the eAER versus measured AER, as were the effects of the previous glycosylated hemoglobin.


CONCLUSIONS
Systematic differences exist between urine ACR and AER, related to gender and other determinants of muscle mass. Use of ACR (or eAER) versus AER yields differences in classification of prevalent albuminuria states and changes in albuminuria states over time. These findings support the use of consistent ascertainment methods over time and further efforts to standardize and optimally interpret measurement of urine albumin excretion.
Younes
Naji
N
Biostatistics Center, George Washington University, 6110 Executive Boulevard, Suite 700, Rockville, MD 20852. cleary@biostat.bsc.gwu.edu, USA.
Cleary
Patricia A
PA
Steffes
Michael W
MW
de Boer
Ian H
IH
Molitch
Mark E
ME
Rutledge
Brandy N
BN
Lachin
John M
JM
Dahms
William
W
D000328:Adult; D000419:Albuminuria / Q000652:urine*; D015415:Biomarkers / Q000652:urine; D003404:Creatinine / Q000652:urine*; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy / Q000652:urine*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012737:Sex Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States
D015415:Biomarkers; D003404:Creatinine; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; C517652:hemoglobin A1c protein, human
JAMA. 2003 Jun 25;289(24):3273-7
12824208
Arch Intern Med. 1991 Sep;151(9):1761-5
1888242
Clin Chem. 2009 Jan;55(1):24-38
19028824
Diabetes Care. 1987 Jul-Aug;10(4):414-8
3622198
J Clin Lab Anal. 1992;6(6):368-74
1432362
J Am Soc Nephrol. 1996 Jun;7(6):930-7
8793803
Diabetes Care. 1999 Jan;22(1):99-111
10333910
Am J Kidney Dis. 2007 Jul;50(1):69-77
17591526
Lancet. 1986 Feb 8;1(8476):307-10
2868172
N Engl J Med. 1993 Sep 30;329(14):977-86
8366922
N Z Med J. 1990 Nov 28;103(902):562-4
2243654
JAMA. 2003 Oct 22;290(16):2159-67
14570951
Am J Clin Nutr. 1983 Mar;37(3):478-94
6829490
N Engl J Med. 1983 Dec 22;309(25):1543-6
6656849
Ann Intern Med. 1999 Mar 16;130(6):461-70
10075613
Clin Chem. 1987 Nov;33(11):2034-8
3677375
Am J Epidemiol. 2002 Jun 15;155(12):1114-9
12048225
Am J Epidemiol. 2004 Dec 1;160(11):1122-31
15561992
J Am Soc Nephrol. 2009 Feb;20(2):436-43
19092125
Kidney Int. 1995 Jun;47(6):1703-20
7643540
J Am Soc Nephrol. 2002 Apr;13(4):1034-1039
11912263
Atherosclerosis. 2008 Mar;197(1):407-14
17681346