NDT Advance Access published online on November 13, 2009
Nephrology Dialysis Transplantation, doi:10.1093/ndt/gfp591
C-reactive protein and microalbuminuria in a multi-ethnic Asian population
1 Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 2 Singapore Eye Research Institute, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 3 Department of Community, Occupational and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 4 Department of Community Medicine, West Virginia University School of Medicine, Morgantown, WV, USA 5 Department of Medicine, Alexandra Hospital, Singapore 6 Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia 7 Department of Endocrinology, Singapore General Hospital, Singapore
Correspondence and offprint requests to: Charumathi Sabanayagam; E-mail: charumathi.s{at}nus.edu.sg
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Abstract |
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Background. C-reactive protein (CRP), a marker for inflammation, has been recently associated with early kidney damage. We examined the association between CRP and micro/macroalbuminuria in a multi-ethnic Asian population using data from two population-based studies in Singapore.
Methods. We studied 5127 individuals, who participated in two separate, cross-sectional studies, the Singapore Prospective Study Program [SP2]/Singapore Cardiovascular Cohort Study 2 (SCCS2), involving 4233 participants of Chinese, Malay and Indian ethnicity, aged 24–95 years in Singapore, and the Singapore Malay Eye Study (SiMES), involving 894 participants of Malay ethnicity, aged 40–80 years. Micro/macroalbuminuria was defined as urinary albumin-to-creatinine ratio of 
17 mg/g for men and 25 g/g for women. CRP was analyzed as a continuous variable and as categories (<1, 1–3, >3 mg/L).
Results. The prevalence of micro/macroalbuminuria in the whole population was 21.1%. The prevalence increased with increasing categories of CRP. Compared with persons with CRP concentrations <1 mg/L, the multivariable odds ratio (OR) (95% confidence interval [CI]) was 1.33 (1.11–1.60) in persons with CRP concentrations 1–3 mg/L and 1.60 (1.30–1.96) in persons with CRP concentrations >3 mg/L; P trend <0.0001. In continuous analysis, each unit increase in log CRP was associated with an OR (95% CI) of 1.20 (1.11–1.28) of having micro/macroalbuminuria (P < 0.0001). This association was independent of potential confounders and was consistent across the two study cohorts with similar effect estimates (OR = 1.6) for micro/macroalbuminuria.
Conclusions. Elevated CRP levels are associated with micro/macroalbuminuria independent of diabetes, hypertension and other potential confounders. This suggests that inflammation may play a role in early kidney damage.
Keywords: albuminuria; inflammation; kidney damage; microvascular disease; Singapore
Received for publication: 15. 6.09
Accepted in revised form: 14.10.09