Diverging association of reduced glomerular filtration rate and albuminuria with coronary and noncoronary events in patients with type 2 diabetes: The renal insufficiency and cardiovascular events (RIACE) Italian multicenter study

OBJECTIVE - Although a reduced estimated glomerular filtration rate (eGFR) was shown to be a powerful independent predictor of cardiovascular disease (CVD), other studies suggested that it confers a much lower risk than albuminuria alone, whereas the combination of the two abnormalities is associated with multiplicative risk. This study aimed at assessing the independent association of previous CVD events, either total or by vascular bed, with eGFR and albuminuria and chronic kidney disease (CKD) phenotypes. RESEARCH DESIGN AND METHODS - This cross-sectional study evaluated 15,773 patients with type 2 diabetes from the Renal Insufficiency And Cardiovascular Events (RIACE) Italian Multicenter Study in 19 outpatient diabetes clinics in years 2007-2008. Albuminuria was assessed by immunonephelometry or immunoturbidimetry. GFR was estimated by the simplified Modification of Diet in Renal Disease Study and the Chronic Kidney Disease-Epidemiology Collaboration equation. CKD was defined as an eGFR 2 or micro- or macroalbuminuria. Major acute CVD events were adjudicated based on hospital discharge records or specialist visits. RESULTS - CVD risk increased linearly with eGFR decline and albuminuria and became significant for values 2 and ≥10.5mg/24 h, respectively. Beyond traditional CVD risk factors, total CVD showed an independent association with albuminuria alone (odds ratio 1.20 [95% CI 1.08-1.33]), reduced eGFR alone (1.52 [1.34-1.73]), and both abnormalities (1.90 [1.66-2.19]). However, coronary events were associated predominantly with reduced eGFR alone, whereas cerebrovascular and peripheral events showed a stronger correlation with the albuminuric CKD phenotypes. CONCLUSIONS - These data, although cross-sectional, show that reduced eGFR, irrespective of albuminuria, is associated with significant CVD, particularly in the coronary district.