Inter-arm systolic blood pressure difference: non-persistence and association with incident cardiovascular disease in the Multi-ethnic Study of Atherosclerosis.

We investigated inter-arm systolic blood pressure (sIAD) difference, reproducibility, and incident cardiovascular disease (CVD). We hypothesized that higher sIAD values have low prevalence and nonpersistence over years, but that CVD risk is higher starting from the time of first high absolute sIAD. In Multi-Ethnic Study of Atherosclerosis participants (n = 6725, 53% female, 45-84 years old), Doppler systolic blood pressure (SBP) measurements were made in both arms (10-minute interval) thrice over 9.5 years. Proportional hazards for CVD (coronary heart disease, heart failure, stroke, peripheral arterial disease (PAD)) over 16.4 years were tested according to time-varying absolute inter-arm difference with covariates: (1) age, gender, race, and clinic; (2) model 1 plus height, heart rate, BP, antihypertensives, BMI, smoking status, lipids, lipid lowering medication, and diabetes. High sIAD was not persistent across exams. Maximum absolute sIAD ≥ 15 mmHg was found at least once in 815 persons. Maximum absolute sIAD had a graded relationship with incident stroke or PAD: 6.2% events; model 2 hazard ratio per 10 mmHg 1.34 (95% CI, 1.15-1.56) and this risk was approximately doubled for maximum absolute sIAD ≥ 15 mmHg vs 0-4 mmHg. Total CVD risk (18.4% events) was increased only for maximum absolute sIAD ≥25 mmHg. Associations with incident CVD did not differ for higher SBP in left vs right arm. A higher maximum absolute sIAD at any exam was associated with greater risk for stroke and PAD especially for values ≥ 15 mmHg, and ≥25 mmHg for other CVD. Measuring SBP between arms may help identify individuals at risk for CVD.