Arm and ankle blood pressure indices, and peripheral artery disease, and mortality: a cohort study

Background and aims: Few studies have compared arm and ankle blood pressures (BPs) with regard to peripheral artery disease (PAD) and mortality. These relationships were assessed using data from three large prospective clinical trials.

Methods: Baseline BP indices included arm systolic BP (SBP), diastolic BP (DBP), pulse pressure (arm SBP minus DBP), ankle SBP, ankle-brachial index (ABI, ankle SBP divided by arm SBP), and ankle-pulse pressure difference (APPD, ankle SBP minus arm pulse pressure). These measurements were categorized into four groups using quartiles. The outcomes were PAD (the first occurrence of either peripheral revascularization or lower-limb amputation for vascular disease), the composite of PAD or death, and all-cause death.

Results: Among 40 747 participants without baseline PAD (age 65.6 years, men 68.3%, diabetes 50.2%) from 53 countries, 1071 (2.6%) developed PAD, and 4955 (12.2%) died during 5 years of follow-up. Incident PAD progressively rose with higher arm BP indices and fell with ankle BP indices. The strongest relationships were noted for ankle BP indices. Compared with people whose ankle BP indices were in the highest fourth, adjusted hazard ratios (95% confidence interval) for each lower fourth were 1.64 (1.31-2.04), 2.59 (2.10-3.20), and 4.23 (3.44-5.21) for ankle SBP; 1.19 (0.95-1.50), 1.66 (1.34-2.05), and 3.34 (2.75-4.06) for ABI; and 1.41 (1.11-1.78), 2.04 (1.64-2.54), and 3.63 (2.96-4.45) for APPD. Similar patterns were observed for mortality. Ankle BP indices provided the highest c-statistics and classification indices in predicting future PAD beyond established risk factors.

Conclusions: Ankle BP indices including the ankle SBP and the APPD best predicted PAD and mortality.