Aims: The association between a low ankle brachial index(ABI) and mortality and vascular morbidity in Japanese individuals with diabetes and the independence of this association from other risk factors have not yet been examined in the primary care setting among a large number of patients.
Methods: An observational prospective cohort study was performed among 3,004 Japanese individuals(2,598 patients with diabetes) to examine all-cause death and cardiovascular disease(CVD) in relation to low ABI(＜0.9) values and other risk factors.
Results: Low ABI values were found in 127 subjects(4.2%) and was associated with smoking, diabetes, hypertension, pulse pressure, glycosylated hemoglobin A1C, lipid profiles, glomerular filtration rate, uric acid and prevalent CVD at baseline. Over 13,242 person-years, 93 deaths and 117 cases of CVD occurred. In a multivariate Cox regression analysis, the hazard ratio for low-normal ABI values was 3.97(95% CI, 2.29 to 6.88) for all-cause death and 2.86(95% CI, 1.83-4.49) for fatal and non-fatal CVD and all-cause death. Similar hazard ratios were found when the subjects were confined to those with diabetes. All risk analyses indicated that age, a low ABI, diabetes, a history of CVD and smoking remained significantly and independently predictive of CVD and all-cause death.
Conclusions: A low ABI exhibits significant cross-sectional associations with conventional risk factors and further more with the glomerular filtration rate, uric acid level and presence of prevalent CVD at baseline, and a low ABI independently predicts subsequent death and cardiovascular events. These findings support the concept that a low ABI is an integrated marker of an excess risk of death and cardiovascular events, independent of conventional risk factors.