OBJECTIVE: The objectives have been to determine the prognostic value of having a low ankle-brachial index (ABI) for different cardiovascular diseases and whether it improves the predictive capacity of the main cardiovascular risk scores proposed for Spain.
DESIGN: Population-based cohort study LOCATION: A health area of the province of Badajoz (Spain) PARTICIPANTS: 2,833 subjects, representative of residents, between 25 and 79 years old, MEASUREMENTS: The ABI was measured at baseline and the first episode of ischemic heart disease or stroke, cardiovascular and total mortality, was recorded during 7 years of follow-up. The hazard ratio (HR) adjusted for cardiovascular risk factors and net reclassification index (NRI) by category, clinical and continuous for the risk functions REGICOR, FRESCO coronary heart disease, FRESCO cardiovascular disease and SCORE, were calculated.
RESULTS: 2,665 subjects were analysed after excluding people with cardiovascular history and loss of follow-up. Low ABI was associated with adjusted HR (95% CI): 6.45 (3.00 - 13.86), 2.60 (1.15 - 5.91), 3.43 (1.39 - 8.44), 2.21 (1.27 - 3.86) for stroke, ischemic heart disease, cardiovascular mortality and total mortality respectively. The ABI improved the NRI (95% CI) in the intermediate risk category according to FRESCO cardiovascular equation by 24.1% (10.1 - 38.2).
CONCLUSIONS: Low ABI is associated with a significant increase in the risk of stroke, ischemic heart disease, cardiovascular mortality and total mortality in our population. The inclusion of ABI improved the reclassification of people at intermediate risk, according to FRESCO cardiovascular, so its use in that risk category would be justified.
Keywords: Ankle brachial index Cardiovascular diseases Cohort studies Enfermedad arterial periférica Enfermedad cardiovascular Epidemiology Epidemiología Estudios de cohortes Medición del riesgo Net reclassification index Peripheral arterial disease Risk assessment Índice de reclasificación neta Índice tobillo brazo