Predictive value of nephelometric and high-performance liquid chromatography assays of urine albumin for mortality in a high-risk Aboriginal population

Wang, Zaimin, Hoy, Wendy E., Nicol, Jennifer L., Wang, Zhiqiang, Su, Qing, Atkins, Robert C. and Polkinghorne, Kevan R. (2008) Predictive value of nephelometric and high-performance liquid chromatography assays of urine albumin for mortality in a high-risk Aboriginal population. American Journal of Kidney Diseases, 52 4: 672-682. doi:10.1053/j.ajkd.2008.03.007


Author Wang, Zaimin
Hoy, Wendy E.
Nicol, Jennifer L.
Wang, Zhiqiang
Su, Qing
Atkins, Robert C.
Polkinghorne, Kevan R.
Title Predictive value of nephelometric and high-performance liquid chromatography assays of urine albumin for mortality in a high-risk Aboriginal population
Journal name American Journal of Kidney Diseases   Check publisher's open access policy
ISSN 0272-6386
1523-6838
Publication date 2008-10-01
Year available 2008
Sub-type Article (original research)
DOI 10.1053/j.ajkd.2008.03.007
Open Access Status Not yet assessed
Volume 52
Issue 4
Start page 672
End page 682
Total pages 11
Place of publication New York, U.S.A.
Publisher W. B. Saunders
Language eng
Subject C1
9203 Indigenous Health
920119 Urogenital System and Disorders
111706 Epidemiology
1103 Clinical Sciences
111701 Aboriginal and Torres Strait Islander Health
Abstract Background: Urine albumin assays by high-performance liquid chromatography (HPLC) yield greater values than immunoassays at lower albumin levels. We compared predictive values of albumin-creatinine ratios (ACRs) by these 2 techniques for mortality in Aboriginal people.
Formatted abstract
Background
Urine albumin assays by high-performance liquid chromatography (HPLC) yield greater values than immunoassays at lower albumin levels. We compared predictive values of albumin-creatinine ratios (ACRs) by these 2 techniques for mortality in Aboriginal people.

Study Design & Setting
This was a longitudinal study of 741 adults in a remote Aboriginal community who participated in a baseline health survey between 1992 and 1998 at ages ranging from 18 to 84 years (mean, 34 years). All natural deaths were documented on follow-up until 2006. Urine albumin concentrations were measured simultaneously by using both nephelometric and HPLC techniques on baseline urine samples retrieved from −70°C storage, as well as creatinine concentrations, and ACRs were derived. Age- and sex-specific tertiles of ACR were compiled. Cox regression analyses were used to evaluate the predictive value of ACR for natural deaths by ACR tertiles and again by z score changes in ACRs as continuous variables.

Results
Participants were followed up for a median of 11 years, during which a total of 119 natural deaths were documented. ACRs on baseline urine samples were greater by HPLC than immunoassay at lower ACR ranges, but were fairly concordant at levels greater than 100 mg/mmol. Levels of ACR by both techniques were strong predictors of death, but correlations of death with ACR tertiles and with ACR levels on a continuum were similar for the 2 techniques.

Limitations
The age- and sex-specific tertiles used might introduce some risk of bias in the assessment of predictive value. In addition, assays were performed on urine after more than 10 years of cold storage.

Conclusion
Despite different absolute values, this study did not show that ACR level by either technique was superior in predicting deaths.
© 2008 by the National Kidney Foundation, Inc.
Keyword Aboriginal people
Albumin-creatinine ratio
Natural deaths
Cox regression
Immuno-assay
High-performance liquid chromatography
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID 921134
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2009 Higher Education Research Data Collection
Excellence in Research Australia (ERA) - Collection
School of Medicine Publications
 
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Citation counts: TR Web of Science Citation Count  Cited 11 times in Thomson Reuters Web of Science Article | Citations
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Created: Thu, 02 Apr 2009, 22:44:35 EST by Amy Wong on behalf of Faculty Of Health Sciences