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

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.

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.

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).

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.