Impact of the Albumin to Creatinine Ratio and the Coronary Artery State on Vascular Events

Albuminuria is an important indicator of cardiovascular risk. However, whether albuminuria predicts cardiovascular events independently of the baseline coronary artery state has not yet been investigated. We measured urinary albumin and creatinine concentrations in 867 consecutive patients who underwent coronary angiography for the evaluation of suspected or established stable coronary artery disease (CAD). Albuminuria was defined as a urinary albumin to creatinine ratio of 30 μg/mg or greater. Prospectively, we recorded the vascular events over 3.2 ± 1.2 years. From our patients, 318 had neither albuminuria nor significant CAD (i.e., coronary stenoses ≥50%) at baseline angiography, 69 had albuminuria but no significant CAD, 343 did not have albuminuria but significant CAD, and 137 had both albuminuria and significant CAD. Compared with the event rate among patients with neither albuminuria nor significant CAD (8.2%), event rates were significantly higher in patients with albuminuria without significant CAD (18.8%; p = 0.002) and in normoalbuminuric patients with significant CAD (19.2%; p <0.001); it was highest in patients with both albuminuria and significant CAD (33.6%; p <0.001). Importantly, event rates were similar in patients with albuminuria free of significant CAD and those with significant CAD but normoalbuminuria (p = 0.767). In conclusion, this is the first study demonstrating that albuminuria per se is a CAD risk equivalent after adjusting for the angiographically proven atherosclerotic state at baseline.