Four-Limb Blood Pressure as Predictors of Mortality in Elderly Chinese

Abstract

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.