Factors Associated with an Abnormal Ankle-Brachial Index in Patients with Resistant Hypertension

Fabio Vieira de Bulhoes, Roque Aras Junior, Luciara Leite Brito, Cristiano Ricardo Bastos de Macedo

The ankle-brachial index (ABI) has been used to identify peripheral arterial occlusive disease and is a marker of macrovascular complications in patients with hypertension.  The objective of the present study was to investigate factors associated with an abnormal ABI in patients with resistant hypertension.  A cross-sectional study with a consecutively selected sample was conducted in a referral cardiology outpatient clinic in Salvador, Bahia, Brazil.  Sociodemographic, anthropometric, clinical, laboratory and echocardiographic data were collected.  The association between abnormal ABI and possible risk factors was evaluated using odds ratios (OR), with their respective 95% confidence intervals (95%CI).  Next, logistic regression analysis was performed, using a hierarchical model.  The prevalence of an abnormal ABI was 19.0%.  Most patients were female (74.8%), black (57.1%), overweight or obese (85.8%), of 40-65 years of age (60.3%), and with education above primary school level (63.8%).  In addition, 44.0% were diabetics; 29.9% had hypercholesterolemia, 21.9% had hypertriglyceridemia and 18.1% had had a cerebrovascular accident.  The factors that remained significantly associated with abnormal ABI in the final model were diabetes (OR=4.11; 95%CI: 1.10-15.50), age >65 years (OR=3.30; 95%CI: 1.13-9.69) and hypercholesterolemia (OR=4.18; 95%CI: 1.12-15.58).  The prevalence of abnormal ABI, albeit not as high as in groups of patients with specific pathologies, was found to be significantly associated with the risk factors traditionally described in the literature.  Therefore, the ABI should be used routinely to evaluate patients with severe hypertension as a method of screening for vascular alterations.