Albuminuria, metabolic syndrome and the risk of mortality and cardiovascular events

Solbu, Marit D.; Kronborg, Jens; Jenssen, Trond G.; Njølstad, Inger; Løchen, Maja-Lisa; Mathiesen, Ellisiv B.; Wilsgaard, Tom; Eriksen, Bjørn O.; Toft, Ingrid

doi:10.1016/j.atherosclerosis.2008.11.002

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Volume 204, Issue 2 , Pages 503-508, June 2009

Albuminuria, metabolic syndrome and the risk of mortality and cardiovascular events

Marit D. Solbu
- Department of Nephrology, University Hospital of North Norway, Tromsø, Norway
- Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway
- Corresponding author at: Department of Nephrology, University Hospital of North Norway, N-9038 Tromsø, Norway. Tel.: +47 776 26000; fax: +47 776 69408.
Jens Kronborg
- Department of Nephrology, Innlandet Hospital Trust, Lillehammer, Norway
- Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway
Trond G. Jenssen
- Department of Nephrology, Rikshospitalet, National University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway
Inger Njølstad
- Institute of Community Medicine, University of Tromsø, Tromsø, Norway
Maja-Lisa Løchen
- Institute of Community Medicine, University of Tromsø, Tromsø, Norway
- Department of Cardiology, University Hospital of North Norway, Tromsø, Norway
Ellisiv B. Mathiesen
- Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway
- Department of Neurology, University Hospital of North Norway, Tromsø, Norway
Tom Wilsgaard
- Institute of Community Medicine, University of Tromsø, Tromsø, Norway
Bjørn O. Eriksen
- Department of Nephrology, University Hospital of North Norway, Tromsø, Norway
- Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway
Ingrid Toft
- Department of Nephrology, University Hospital of North Norway, Tromsø, Norway
- Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway

Received 10 September 2008; received in revised form 21 October 2008; accepted 2 November 2008. published online 17 December 2008.

Abstract

Aim

Increased urinary albumin-excretion is a cardiovascular risk-factor. The cardiovascular risk of the metabolic syndrome (MetS) is debated. The aim of the present prospective, population-based study of non-diabetic individuals was to examine the association between low-grade urinary albumin-excretion, MetS, and cardiovascular morbidity and all-cause mortality.

Methods

5215 non-diabetic, non-proteinuric men and women participating in the Tromsø Study 1994–1995 were included. Urinary albumin–creatinine ratio (ACR) was measured in three urine samples. The participants were categorized into four groups by the presence/absence of MetS (the International Diabetes Federation definition) and ACR in the upper tertile (≥0.75mg/mmol).

Results

Median follow-up time was 9.6 years for first ever myocardial infarction, 9.7 years for ischemic stroke and 12.4 years for mortality. High ACR (upper tertile)/MetS was associated with increased risk of myocardial infarction (hazard ratio (HR) 1.75; 95% confidence interval (CI): 1.30–2.37, p<0.001), stroke (HR 2.48; 95% CI: 1.66–3.71, p<0.001), and all-cause mortality (HR 1.63; 95% CI: 1.32–2.01, p<0.001) compared to reference (low ACR/no MetS). Similar associations were found for the high ACR/no MetS group. Low ACR/MetS was associated with myocardial infarction only (HR 1.82; 95% CI: 1.39–2.37, p<0.001). MetS predicted neither stroke nor mortality. Adjusted for its individual components, MetS was not associated with any end-point.

Conclusions

ACR≥0.75mg/mmol was associated with cardiovascular morbidity and all-cause mortality independently of MetS. MetS was not associated with any end-point beyond what was predicted from its components. Thus, low-grade albuminuria, but not MetS, may be used for risk stratification in non-diabetic subjects.

Keywords: Albuminuria, Metabolic syndrome, Cardiovascular risk, All-cause mortality, Epidemiology