Inter-arm blood pressure difference and mortality: a cohort study in an asymptomatic primary care population at elevated cardiovascular risk

Br J Gen Pract. 2016 May;66(646):e297-308. doi: 10.3399/bjgp16X684949. Epub 2016 Apr 14.


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.

Keywords: blood pressure; cardiovascular diseases; cohort studies; inter-arm difference; primary care; subclavian artery stenosis.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Arm / blood supply*
  • Aspirin / therapeutic use
  • Blood Pressure / physiology*
  • Blood Pressure Determination / methods*
  • Body Mass Index
  • Cross-Sectional Studies
  • Female
  • Follow-Up Studies
  • Humans
  • Hypertension / complications
  • Hypertension / diagnosis*
  • Hypertension / mortality
  • Male
  • Middle Aged
  • Peripheral Vascular Diseases / diagnosis*
  • Peripheral Vascular Diseases / mortality
  • Peripheral Vascular Diseases / physiopathology
  • Platelet Aggregation Inhibitors / therapeutic use
  • Population Surveillance
  • Primary Health Care*
  • Risk Factors
  • Scotland / epidemiology


  • Platelet Aggregation Inhibitors
  • Aspirin