Ankle brachial index, C-reactive protein, and central augmentation index to identify individuals with severe atherosclerosis

Objectives We examined the ability of ankle brachial index, C-reactive protein and central augmentation index to identify individuals in the general population with severe atherosclerosis, diagnosed as those with ischaemic cardiovascular disease. Methods and results We examined 4159 randomly sampled individuals from the Danish general population, of which 250 had severe atherosclerosis. After adjustment for gender and age, individuals with ankle brachial index of 0.71-0.90 and < 0.70 vs. 0.91-1.10 had odds ratios for severe atherosclerosis of 1.6 (95%CI:1.1-2.3) and 2.9 (1.9-4.6), respectively. C-reactive protein of > 3.0 or 1.0-3.0 mg/L vs. < 1.0 mg/L as well as central augmentation index in quintiles did not identify individuals with severe atherosclerosis, and did not improve further the ability of ankle brachial index to identify such individuals. On a continuous scale using receiver operating characteristics curves, presence of severe atherosclerosis was predicted by ankle brachial index (P=0.00000003), C-reactive protein (P=0.000003), as well as central augmentation index (P=0.001); these three curves did not differ. Conclusion Ankle brachial index < 0.9 identify individuals with severe atherosclerosis in the general population, while C-reactive protein in three groups and central augmentation index in quintiles did not. On a continuous scale, all three variables predicted severe atherosclerosis.