Comparison of ambulatory blood pressure measurement with home, office and pharmacy measurements: is arterial blood pressure measured at pharmacy reliable?

Rationale, aims and objectives: Standardizing arterial blood pressure (BP) measurement is difficult because of different performers like doctor or pharmacy employee. We investigated the reliability between different BP measurement methods.

Methods: The study was conducted in an internal medicine service with 160 patients in Ankara, Turkey. First, the subjects' BP was measured by doctor. Then, 24-hour BP monitoring devices were placed. Participants were then instructed to measure their BPs both at home and in pharmacy. The next day, arterial BP was measured by the doctor for the second time.

Results: The prevalence rates of masked and white coat hypertension were 8.8% (n = 14) and 8.1% (n = 13), respectively. There was no statistically significant differences between ambulatory measurement and home, office and pharmacy measurements (P > 0.05). The consistency rate between ambulatory and home measurements was 97.5% (kappa = 0.947, P < 0.001). The consistency rate between ambulatory and pharmacy measurements was 82.5% (kappa = 0.634, P < 0.001). When compared with ambulatory measurement, the most sensitive (98.0%) and most specific (96.8%) method was home measurement. There was a moderate positive correlation between ambulatory and other measurements in both systolic and diastolic values. There was a positive and very strong correlation between ambulatory and home measurements of systolic and diastolic ABP values (respectively; r = 0.926 and r = 0.968) and there was a statistically significant relation between these measurements (P < 0.001).

Conclusion: The results of all measurement methods were close to each other. The most sensitive and specific method was home measurement when compared with ambulatory measurement. But both office and pharmacy measurements had also high sensitivity and specificity.