Ankle Brachial Index is a strong predictor of mortality in hypertensive patients: results of a five-year follow-up study

Background: In the hypertensive population, the peripheral arterial disease (PAD) is considered one of the target organ damages. Ankle Brachial Index (ABI) measurement represents the widely accepted clinical method that may objectively detect the presence of PAD. The study aimed to assess how PAD revealed by ABI predicts mortality in patients with hypertension.Methods: In the follow-up time (5 years period) of the Hungarian ERV Study, a large scale, multicenter observational study, recruiting hypertensive subjects between 50-75 years, the association of PAD with the survival time was analysed. Several multivariate, interval-censored survival models were developed to assess this association. Results: Among the 21892 enrolled hypertensive patients, the prevalence of PAD (ABI<0.9) was 14.4%. The crude death rate was 5.44% (1190 cases) over the available observational period. In multivariate models male sex, myocardial infarction in patients' history, diabetes, renal failure, PAD and cardiovascular risk (SCORE risk) were significantly associated with mortality. Lower ABI showed a continuous, close to linear association with worse survival. PAD was predictive for mortality risk in all SCORE patient groups. Conclusions: Low ABI is a strong predictor of mortality in hypertensive patients between the age 50-75, even after adjustment for several potential confounders. The association is linear, with no apparent cut-off, suggesting that ABI should be handled as a continuous variable. The detection of PAD in hypertensives may contribute to the determination of total cardiovascular risk in hypertensive population.