Purpose: Hypertension guidelines recommend measuring blood pressure (BP) on both arms, since an abnormal inter-arm difference (IAD) in BP is associated with an increased risk of vascular abnormalities and cardiovascular (CV) disease. We tested whether an automatic oscillometric BP monitor allowing simultaneous both arm BP measurement might be effective for screening of subjects with potential vascular disease.
Materials and methods: 220 consecutive subjects from an unselected sample of individuals of a small Italian community were screened using an automated upper-arm electronic BP monitor (Microlife WatchBP Office). Seated BP was measured in triplicate at 1 min interval. Demographic and clinical data were collected prior to any BP measurement. An average IAD difference >20 mmHg for systolic (S) and/or >10 mmHg for diastolic (D) BP was considered abnormal.
Results: In 9 subjects (4.1%) an abnormal IAD was found, with lower BPs measured in the non-dominant arm (147 ± 28/78 ± 9 vs. 154 ± 15/92 ± 11 mmHg dominant, p<.01). Subjects with a significant IAD were significantly older (71 ± 8 vs. 57 ± 15 years, p=.005), had a greater body mass index (BMI: 32 ± 7 vs. 25 ± 4 kg/m2, p=.0001), higher BP levels (154 ± 15/92 ± 11 vs. 133 ± 18/80 ± 10 mmHg, p=.001) and were more likely to report obesity (56 vs. 13%, p=.001), a history of hypertension (67 vs. 35%, p=.044) or cardiovascular disease (33 vs. 10%, p=.034) than subjects with normal IAD. In a multivariate analysis, a higher BMI [odds ratio (95% confidence interval): 1.29 (1.11, 1.51)] and SBP [1.06 (1.01, 1.10)] were significantly associated with a larger risk of an abnormal IAD (p=.001 and p=.012, respectively).
Conclusions: An abnormal IAD in BP is associated with a larger prevalence of CV risk factors and CV disease. Our study confirms that simultaneous both arm BP measurement must always be accomplished in subjects at risk for or with established CV disease.
Keywords: Blood pressure measurement; Italy; cardiovascular disease; hypertension; inter-arm difference in blood pressure.