Higher systolic blood pressure difference in left not right upper limb is associated with all-cause mortality risk in a community-based population

This study investigated inter-arm systolic blood pressure difference (IASBPD) and mortality risks in 8628 Chinese community residents from an atherosclerosis cohort. IASBPD was calculated by subtracting the systolic blood pressure of the left arm from that of the right arm. Participants were categorized as |IASBPD| <10 mmHg or ≥10 mmHg. These groups were further subdivided into four categories according to specific IASBPD values. The endpoints included all-cause mortality and cardiovascular mortality. Over a median follow-up of 9.87 years, a total of 442 all-cause and 138 cardiovascular deaths were recorded. Compared to |IASBPD| <10 mmHg group, the |IASBPD| ≥10 mmHg group had a 53% increase in all-cause mortality risk (adjusted HR = 1.53, P = 0.002) and a 71% increase in cardiovascular mortality risk (adjusted HR = 1.71, P = 0.021). When comparing specific IASBPD, no significant increase in all-cause mortality risk was observed in the group with a right arm higher ≥10 mmHg (adjusted HR = 1.17, P = 0.507) or in the group with a left arm higher ≤10 mmHg (adjusted HR = 0.90, P = 0.329). Conversely, the left arm higher >10 mmHg group demonstrated a significant 59% increase in the risk of all-cause mortality (adjusted HR = 1.59, P = 0.013). While the association with cardiovascular mortality was not statistically significant in this subgroup, the trend paralleled that observed for all-cause mortality. In conclusion, an elevated IASBPD is significantly associated with all-cause and cardiovascular mortality risks, with higher IASBPD in the left arm showing a stronger link to all-cause mortality risk.