Inter-arm blood pressure difference and mortality: a cohort study in an asymptomatic primary care population at elevated cardiovascular risk.
British Journal of General Practice
Royal College of General Practitioners
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Under indefinite embargo due to publisher policy. The final version is freely available from the publisher via the DOI in this record.
BACKGROUND: Differences in blood pressure between arms are associated with increased cardiovascular mortality in cohorts with established vascular disease or substantially elevated cardiovascular risk. AIM: To explore the association of inter-arm difference (IAD) with mortality in a community-dwelling cohort that is free of cardiovascular disease. DESIGN AND SETTING: Cohort analysis of a randomised controlled trial in central Scotland, from April 1998 to October 2008. METHOD: Volunteers from Lanarkshire, Glasgow, and Edinburgh, free of pre-existing vascular disease and with an ankle-brachial index ≤0.95, had systolic blood pressure measured in both arms at recruitment. Inter-arm blood pressure differences were calculated and examined for cross-sectional associations and differences in prospective survival. Outcome measures were cardiovascular events and all-cause mortality during mean follow-up of 8.2 years. RESULTS: Based on a single pair of measurements, 60% of 3350 participants had a systolic IAD ≥5 mmHg and 38% ≥10 mmHg. An IAD ≥5 mmHg was associated with increased cardiovascular mortality (adjusted hazard ratio [HR] 1.91, 95% confidence interval [CI] = 1.19 to 3.07) and all-cause mortality (adjusted HR 1.44, 95% CI = 1.15 to 1.79). Within the subgroup of 764 participants who had hypertension, IADs of ≥5 mmHg or ≥10 mmHg were associated with both cardiovascular mortality (adjusted HR 2.63, 95% CI = 0.97 to 7.02, and adjusted HR 2.96, 95% CI = 1.27 to 6.88, respectively) and all-cause mortality (adjusted HR 1.67, 95% CI = 1.05 to 2.66, and adjusted HR 1.63, 95% CI = 1.06 to 2.50, respectively). IADs ≥15 mmHg were not associated with survival differences in this population. CONCLUSION: Systolic IADs in blood pressure are associated with increased risk of cardiovascular events, including mortality, in a large cohort of people free of pre-existing vascular disease.
Christopher E Clark is supported by a National Institute for Health Research (NIHR) clinical lectureship award. This work was funded jointly, as part of his PhD studies, by the NIHR Collaboration for Leadership in Applied Health Research and Care (CLAHRC) for the South West Peninsula at the Royal Devon and Exeter NHS Foundation Trust, and by a grant from the Scientific Foundation Board of the Royal College of General Practitioners (grant number SFB-2009-06). Rod S Taylor was supported by the NIHR CLAHRC for the South West Peninsula at the Royal Devon and Exeter NHS Foundation Trust. Angela C Shore is supported by the NIHR Exeter clinical research facility. The views expressed in this publication are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health in England. Data extraction for this study was funded by the South West General Practice Trust. The AAA trial was supported by the British Heart Foundation and the Chief Scientist’s Office of the Scottish Government.
Vol. 66, pp. e297 - e308
Place of publication