The difference in blood pressure readings between arms and survival: primary care cohort study
BMJ 2012; 344 doi: https://doi.org/10.1136/bmj.e1327 (Published 20 March 2012) Cite this as: BMJ 2012;344:e1327
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- Christopher E Clark, clinical academic fellow1,
- Rod S Taylor, professor in health services research, medical statistician1,
- Angela C Shore, professor of cardiovascular science2,
- John L Campbell, professor of general practice and primary care1
- 1Primary Care Research Group, Institute of Health Services Research, Peninsula College of Medicine and Dentistry, University of Exeter, Devon EX1 2LU, UK
- 2Institute of Biomedical and Clinical Science, Peninsula College of Medicine and Dentistry, and Peninsula NIHR Clinical Research Facility, University of Exeter, Devon, UK
- Correspondence to: C E Clark christopher.clark{at}pms.ac.uk
- Accepted 13 January 2012
Abstract
Objective To determine whether a difference in systolic blood pressure readings between arms can predict a reduced event free survival after 10 years.
Design Cohort study.
Setting Rural general practice in Devon, United Kingdom.
Participants 230 people receiving treatment for hypertension in primary care.
Intervention Bilateral blood pressure measurements recorded at three successive surgery attendances.
Main outcome measures Cardiovascular events and deaths from all causes during a median follow-up of 9.8 years.
Results At recruitment 24% (55/230) of participants had a mean interarm difference in systolic blood pressure of 10 mm Hg or more and 9% (21/230) of 15 mm Hg or more; these differences were associated with an increased risk of all cause mortality (adjusted hazard ratio 3.6, 95% confidence interval 2.0 to 6.5 and 3.1, 1.6 to 6.0, respectively). The risk of death was also increased in 183 participants without pre-existing cardiovascular disease with an interarm difference in systolic blood pressure of 10 mm Hg or more or 15 mm Hg or more (2.6, 1.4 to 4.8 and 2.7, 1.3 to 5.4). An interarm difference in diastolic blood pressure of 10 mm Hg or more was weakly associated with an increased risk of cardiovascular events or death.
Conclusions Differences in systolic blood pressure between arms can predict an increased risk of cardiovascular events and all cause mortality over 10 years in people with hypertension. This difference could be a valuable indicator of increased cardiovascular risk. Bilateral blood pressure measurements should become a routine part of cardiovascular assessment in primary care.
Footnotes
We thank the staff and patients of the Mid Devon Medical Practice for their support and participation in this study.
Contributors: CEC conceived the study, collected the data, undertook primary analyses, and drafted the manuscript. RST undertook and supervised data analysis and contributed to the manuscript. ACS and JLC advised on data analysis and presentation and contributed to the manuscript. CEC wlll act as guarantor for this study.
Funding: This research was supported by the Scientific Foundation Board of the Royal College of General Practitioners (grant No SFB-2009-06), the South West GP Trust, and the National Institute for Health Research (NIHR) Peninsula Collaboration for Leadership in Applied Health Research and Care, a NIHR funded collaboration of the Peninsula College of Medicine and Dentistry, University of Exeter, University of Plymouth, and NHS South West. The project was also supported by the NIHR Peninsula Clinical Research Facility. The views and opinions expressed in this paper are those of the authors and not necessarily those of the NHS, the NIHR, or the Department of Health.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; and no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: This study was approved by the North and East Devon Research Ethics Committee (No 2000/12/158).
Data sharing: No additional data available.
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