The predictive value of blood pressure (BP) for cardiovascular morbidity and mortality diminishes in the elderly, which may be confounded and compensated by the BP differences across the 4 limbs, markers of peripheral arterial disease. In a prospective elderly (≥60 years) Chinese study, we performed simultaneous 4-limb BP measurement using an oscillometric device in the supine position, and calculated BP differences between the 4 limbs. At baseline, the mean age of the 3133 participants (1383 men) was 69 years. During 4 years (median) of follow-up, all-cause and cardiovascular deaths occurred in 203 and 93 subjects, respectively. In multiple regression analyses, arm BPs on the higher arm side of systolic BP did not predict mortality (P≥0.06) except for a negative association between mean arterial pressure and total mortality (P=0.04). However, in adjusted analyses, the hazard ratios associated with a 1-SD decrease in ankle-brachial BP index or increase in interarm or interankle BP difference were 1.15 to 1.23 for total mortality (P≤0.01) and 1.17 to 1.24 for cardiovascular mortality (P≤0.04). In categorical analyses, similar results were observed for a decreased ankle-brachial index (≤0.90, ≤0.95, or ≤1.00) or increased interarm or interankle difference (≥15 mm Hg or ≥10 mm Hg). In conclusion, in the elderly, above and beyond arm BP level and together with ankle-brachial index, the interarm and interankle BP differences improve prediction of mortality. Simultaneous 4-limb BP measurement has become feasible with current technology and might be useful in cardiovascular prevention.
Keywords: Chinese; ankle-brachial index; elderly; interankle blood pressure difference; interarm blood pressure difference; mortality.