Is 7-days home BP measurement comparable to 24-hours Ambulatory BP Measurement?

High blood pressure (BP) or hypertension is a significant risk factor for the global burden of cardiovascular diseases. Home blood pressure measurements (HBPM) have been recommended for hypertension diagnosis, treatment initiation and medication titration, but guidelines for the number of measurements and duration are inconsistent. This study compared the accuracy of 3 home BP measurements per day for seven days with 24-hour ambulatory BP measurements. We examined 24-hour ambulatory BP measurements (ABPM) and HBPM during-morning, afternoon, and evening each day for seven days in healthy community living volunteers. Standardized Bland-Altman scatterplots and limits of agreement (LOA) were used to assess absolute reliability and the variability of measurement biases. We used nonparametric Mann-Whitney U-tests to compare the mean (SD) of the devices. Correlations between HBPM and 24-hour ABPM measurements were statistically significant at p<0.05. The high correlation coefficient (r=0.75) was observed between the systolic BP retrieved from two devices compared to moderate correlation (r=0.46) among diastolic BP. A significant difference was found for systolic BP (P<0.05) between the HBPM and ABPM but was non-significant for diastolic BP (P>0.05). In Bland-Altman plots, the LOA between HBPM and ABPM was 0.07-26.23 mmHg for SBP and 11.24 -16.20 mmHg for DBP. The overall mean difference (bias) in SBP and DBP was 13.08 and 2.48, respectively. Our results suggest that HBPM three times per day for seven days can potentially be used where ABPM is unavailable. Further studies in a diverse group of people with hypertension are needed.