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Inter-arm systolic blood pressure difference (sIAD) has recently been recognized as a risk factor for cardiovascular mortality. However, sIAD reproducibility remains unclear.
We evaluated between-visit reproducibility of sIAD in hypertensive patients. We examined 1,875 hypertensive participants aged 20 years and older (mean age of 61.1 years, 45.1% female) from nine primary clinics and 27 secondary and tertiary hospitals. Blood pressure (BP) in both arms was automatically and simultaneously measured in triplicate using a cuff-oscillometric BP device. Increased sIAD was defined as ≥10 mmHg of the absolute difference in averaged systolic BPs between left and right arms.
Overall mean sIAD was 4.28 ± 4.10 mmHg. The prevalence of increased sIAD was 7.7%. Intraclass correlation coefficient was 0.706 (95% confidence interval 0.683-0.728) between first and second measurements, 0.693 (95% confidence interval 0.668-0.715) between second and third measurement, 0.661 (95% confidence interval 0.635-0.686) between first and third measurements. The Cohen’s kappa value was 0.387 (95% CI 0.339 to 0.436) between first and second measurements, 0.409 (95% CI 0.359 to 0.469) between second and third measurements, 0.353 (95% CI 0.303 to 0.40) between first and third measurements for increased sIAD.
The reproducibility in sIAD determination among three measurements lacked agreement in hypertensive patients. Further studies should identify relevant variables and characteristics of the poor reproducibility.