Comparison of office, home and ambulatory blood pressure measurements in hypertensive and suspected hypertensive SWICOS participants

PLAIN LANGUAGE SUMMARY What is already known? Comparing blood pressure measurements in the doctor's office or clinic (OBPM) with out-of-office measurements (either self-measurement at home (HBPM) or ambulatory over 24 hours during both day and night times (ABPM)) improves the accuracy of hypertension diagnosis. Why was the study done? This study was done to provide additional information by comparing HBPM and ABPM in individuals with elevated OPBMs (& GE;140/& GE;90mmHg), who participated in the Swiss Longitudinal Cohort Study (SWICOS) What was found? Our study confirmed differences between office and out-of-office measurements. In 60% of the study participants, ABPM or HBPM confirmed the elevated OBPM but only around half of these participants were treated with antihypertensive drugs. A high proportion of the participants (28%) had white coat hypertension. What does this study add? Our study adds to the literature already available on this issue by reporting on data obtained from a cohort of individuals living in a countryside area of Southern Switzerland. This study also showed that HBPM might underestimate BP in the younger working population. How might this impact on clinical practice? The findings of this population-based study support the European Society of Hypertension recommendations for wider use of out-of-office blood pressure measurement for the confirmation of hypertension in individuals with elevated OBPM to avoid underdiagnosis and uncontrolled hypertension. In the young working population, ABPM should be used instead of only HBPM to confirm hypertension. Purpose Hypertension should be confirmed with the use of home BP measurement (HBPM) or 24h ambulatory BP measurement (ABPM). The aim of our study was to compare measurements obtained by OBPM, HBPM and ABPM in individuals with elevated OBPM participating in the population-based Swiss Longitudinal Cohort Study (SWICOS). Material and Methods Participants with OBPM & GE;140/90 mmHg assessed their BP using HBPM and ABPM. The cut-off for hypertension was & GE;135/85 mmHg for HBPM, & GE;130/80 mmHg for ABPM. White-coat hypertension (WCH) was defined as normal HPBM and ABPM in participants not taking antihypertensive drugs. Uncontrolled hypertension was defined as hypertension in HBPM or ABPM despite antihypertensive treatment. Results Of 72 hypertensive subjects with office BP & GE;140/90 mmHg and valid measurements of HBPM and ABPM, 39 were males (aged 62.8 & PLUSMN; 11.8y), 33 were females (aged 57.4 & PLUSMN; 14.2y). Hypertension was confirmed with HBPM and ABPM in 17 participants (24%), with ABPM only in 24 further participants (33%), and with HBPM only in 2 further participants (3%). Participants who had hypertension according to ABPM but not HBPM were younger (59 & PLUSMN; 11 y versus 67 & PLUSMN; 16 y; p < 0.001) and more frequently still working (83% versus 23%; p < 0.001). The prevalence of WCH was 28%. Among the 32 subjects taking antihypertensive drugs, uncontrolled hypertension was found in 49%. Conclusion This population-based study found a high prevalence of WCH and potential uncontrolled hypertension among individuals with elevated OBPM. This study, therefore, supports the ESH recommendations of complementing OBPM by ABPM or HBPM. The use of HBPM instead of ABPM for the confirmation of hypertension in individuals with elevated OBPM might lead to underdiagnosis and uncontrolled hypertension, in particular in the younger working population. In these individuals, this study suggests using ABPM instead of HBPM.