Comparison of Different Automated Office Blood Pressure Measurement Devices: Evidence of Nonequivalence and Clinical Implications.

BACKGROUND: Automated office blood pressure (AOBP) measuring devices are increasingly recommended as preferred blood pressure (BP) diagnostic tools, but it is unclear how they compare and how clinical environments impact their performance. METHODS: This prospective randomized factorial parallel 4-group study compared BP estimates by BpTRU (VSM MedTech, Vancouver, BC, Canada) and Omron HEM 907 (Omron Healthcare, Kyoto, Japan) devices in closed vs open areas. Patients diagnosed with hypertension were recruited during office visits. After baseline open-room AOBP measurement with the BpTRU, patients had a second BP measurement with either the BpTRU or HEM 907 in either open or closed areas. Absolute BP levels and differences between the first and second measurements were compared. Diagnostic performance was also assessed. RESULTS: Two hundred fifty-eight patients were studied. Their mean age was 66.2 ± 12.0 years, and 62% were men. The mean of first AOBP estimates was 127.4/73.3 mm Hg. Analyses of subsequent measurements revealed no influence of open or closed areas on BP means and diagnostic performance. Conversely, the Omron HEM 907 exceeded BpTRU systolic BP measurements by 4.6 mm Hg (< 0.01) in closed areas and by 3.9 mm Hg (< 0.01) in open areas. The discrepancy between devices was amplified at lower BP levels. CONCLUSIONS: Although different areas did not influence BP estimates, the Omron HEM 907 significantly exceeded BpTRU measurements on average and especially at lower BP levels. These differences should be considered when interchanging devices and could have clinical decision impacts in a population of patients treated for hypertension. Our results support the constant use of only 1 device type in a given clinic.

The Gap Between Manual and Automated Office Blood Pressure Measurements Results at a Hypertension Clinic.

BACKGROUND: Blood pressure (BP) readings taken in clinics are often higher than BP readings taken in a research setting. Recent guidelines and clinical trials have highlighted the necessity of using automated office blood pressure (AOBP) devices and standardizing measurement procedures. The goal of the present study was to compare AOBP vs manual BP measurement in both research and clinical environments in which operators and devices were the same and measurement procedures were standardized and optimal. METHODS: Clinical manual BP and AOBP measurement estimates were gathered from a retrospective cohort of patients followed in a hypertension clinic. Research AOBP and manual BP measurement data were obtained from past research studies. Descriptive statistics and agreement analyses with Cohen kappa coefficients were developed. The AOBP/manual BP measurement gap between clinical and research follow-up was compared using an unpaired t test. RESULTS: Two hundred eighty-eight patients were included in the clinical cohort, and 195 patients contributed to research-grade BP data. All patients had hypertension. AOBP averages were lower than manual measurement averages in both clinical (-3.6 ± 14.9 mm Hg / -3.0 ± 8.8 mm Hg) and research (-2.7 ± 10.0 / -2.4 ± 6.3 mm Hg) environments. The gap between measurement methods did not differ between research and clinical data. Cohen kappa coefficient was lower in the clinical context because of greater variability and more time between BP measurements (5.5 ± 2.9 months). CONCLUSIONS: Manual BP readings were slightly higher than AOBP estimates. The difference was not influenced by the real-world context of clinical practice. Office nonautomated BP measurements may still be valuable if measurement procedures are well standardized and performed by trained nurses.