High ACR, incident heart disease linked in blacks.
A higher urinary albumin-to-crea- tinine ratio was associated with an increased risk of incident coronary heart disease in black adults in a large, population-based study.
No such association was seen in white adults in the prospective cohort study, suggesting that blacks are more susceptible to vascular injury, said Dr. Orlando M. Gutierrez of the University of Alabama at Birmingham, reporting on behalf of the Reasons for Geographic and Racial Differences in Stroke (REGARDS) investigators.
Over a mean follow-up period of 4.5 years, 616 incident coronary heart disease events - 421 nonfatal Mis and 195 CHD deaths - occurred in 23,273 individuals who were free of CHD at baseline. The incidence rates of CHD per 1,000 person-years of follow-up increased with increasing al- bumin-to-creatinine ratio (ACR) in these patients, and the increases were significantly greater for black adults, the researchers reported.
Age- and sex-adjusted incidence rates were nearly 1.5-fold greater in blacks than in whites in the two highest categories of ACR: For black vs. white adults with an ACR of 30-300 mg/g, the incidence rates per 1,000 person-years were 11.2 and 8.0, respectively, and for those with ACR greater than 300 mg/g, the rates were 20.6 and 13.6, respectively, both significant differences.
After adjustment for traditional cardiovascular risk factors and medications, higher baseline urinary ACR (greater than 300 mg/g vs. less than 10 mg/g) was associated with greater risk of incident CHD among blacks, but not whites (hazard ratios of 3.21 and 1.49, respectively).
A similar association was not seen for recurrent CHD. Over 4.4 years of follow-up, 468 recurrent CHD events - 279 nonfatal Mis and 189 CHD deaths
occurred in 4,934 adults who had CHD at baseline. No differences were seen between black and white adults in this group with respect to baseline urinary ACR and first recurrent CHD event (JAMA 2013; 310:706-13).
REGARDS comprised adults in the United States aged 45 years and older at baseline between 2003 and 2007, and oversampled those who self-re- ported as black and those living in the stroke belt.
Blacks are known to have higher levels of urinary albumin excretion than those of whites - a finding that may contribute to racial disparities in cardiovascular outcomes. Previous REGARDS findings showed that an association between urinary ACR and incident stroke differed by race, and that higher urinary ACR was independently associated with a greater risk of incident stroke in blacks, but not whites, the researchers said.
However, little is known about racial differences with respect to the association of urinary ACR and cardiovascular outcomes apart from stroke, they noted.
"These findings confirm the results of prior studies showing that urinary ACR is an important biomarker for CHD risk in the general population, even among individuals with ACR values that are less than the current threshold for defining microalbuminuria (30 mg/g)," they noted. "To our knowledge, this is the first study to demonstrate that the higher risk of incident CHD associated with excess ACR differs by race."
The National Institute of Neurological Disorders and Stroke, National Heart, Lung, and Blood Institute, National Institute of Diabetes and Digestive and Kidney Diseases, and Amgen funded the work. Several authors disclosed ties with Amgen, REATA Pharmaceuticals, Arbor Research, Sanofi-Genzyme, and/ or diaDexus.
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|Publication:||Internal Medicine News|
|Article Type:||Clinical report|
|Date:||Sep 15, 2013|
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