Context Blood pressure (BP) measurement in clinicians' offices with a mercury
sphygmomanometer has numerous drawbacks. In contrast, the use of home BP measurement
improves measurement precision and reproducibility. However, data about its
prognostic value are lacking.
Objective To assess the prognostic value of home vs office BP measurement by general
practitioners in a European population of elderly patients being treated for
Design, Setting, and Participants Office and home BP and cardiac risk factors were measured at baseline
in a cohort of 4939 treated hypertensive patients (mean age, 70 [SD, 6.5]
years; 48.9% men) who were recruited and followed up by their usual general
practitioners without specific recommendations about their management. The
cohort was then followed up for a mean of 3.2 (SD, 0.5) years. The thresholds
defining uncontrolled hypertension were at least 140/90 mm Hg for office BP
and 135/85 mm Hg for home BP.
Main Outcome Measures The primary end point was cardiovascular mortality. Secondary end points
were total mortality and the combination of cardiovascular mortality, nonfatal
myocardial infarction, nonfatal stroke, transient ischemic attack, hospitalization
for angina or heart failure, percutaneous transluminal coronary angioplasty,
or coronary artery bypass graft surgery.
Results At the end of follow-up, clinical status was known for 99.9% of patients.
At least 1 cardiovascular event had occurred in 324 (incidence, 22.2/1000
patient-years). For BP self-measurement at home, each 10-mm Hg increase in
systolic BP increased the risk of a cardiovascular event by 17.2% (95% confidence
interval [CI], 11.0%-23.8%) and each 5-mm Hg increase in diastolic BP increased
that risk by 11.7% (95% CI, 5.7%-18.1%). Conversely, for the same increase
in BP observed using office measurement, there was no significant increase
in the risk of a cardiovascular event. In a multivariable model with patients
having controlled hypertension (normal home and office BP) as the referent,
the hazard ratio of cardiovascular events was 1.96 (95% CI, 1.27-3.02) in
patients with uncontrolled hypertension (high BP with both measurement methods),
2.06 (95% CI, 1.22-3.47) in patients with normal office BP and elevated home
BP, and 1.18 (95% CI, 0.67-2.10) in patients with elevated office BP and normal
Conclusions Our findings suggest that home BP measurement has a better prognostic
accuracy than office BP measurement. Blood pressure should systematically
be measured at home in patients receiving treatment for hypertension.