Home blood pressure monitoring in clinical practice: how many measurements and when?

The impact of a multidisciplinary information technology-supported program on blood pressure control in primary care

BACKGROUND

Hypertension is a leading mortality risk factor yet inadequately controlled in most affected subjects. Effective programs to address this problem are lacking. We hypothesized that an information technology-supported management program could help improve blood pressure (BP) control.

METHODS AND RESULTS

This randomized controlled trial included 223 primary care hypertensive subjects with mean 24-hour BP >130/80 and daytime BP >135/85 mm Hg measured with ambulatory monitoring (ABPM). Intervention subjects received a BP monitor and access to an information technology-supported adherence and BP monitoring system providing nurses, pharmacists, and physicians with monthly reports. Control subjects received usual care. The mean (+/-SD) follow-up was 348 (+/-78) and 349 (+/-84) days in the intervention and control group, respectively. The primary end point of the change in the mean 24-hour ambulatory BP was consistently greater in intervention subjects for both systolic (-11.9 versus -7.1 mm Hg; P<0.001) and diastolic BP (-6.6 versus -4.5 mm Hg; P=0.007). The proportion of subjects that achieved Canadian Guideline target BP (46.0% versus 28.6%) was also greater in the intervention group (P=0.006). We observed similar BP declines for ABPM and self-recorded home BP suggesting the latter could be an alternative for confirming BP control. The intervention was associated with more physician-driven antihypertensive dose adjustments or changes in agents (P=0.03), more antihypertensive classes at study end (P=0.007), and a trend toward improved adherence measured by prescription refills (P=0.07).

CONCLUSIONS

This multidisciplinary information technology-supported program that provided feedback to patients and healthcare providers significantly improved blood pressure levels in a primary care setting.

Ambulatory blood pressure monitoring versus self-measurement of blood pressure at home: correlation with target organ damage

OBJECTIVE

Ambulatory blood pressure (BP) monitoring and home blood pressure measurements predicted the presence of target organ damage and the risk of cardiovascular events better than did office blood pressure.

METHODS

To compare these two methods in their correlation with organ damage, we consecutively included 325 treated (70%) or untreated hypertensives (125 women, mean age = 64.5 +/- 11.3) with office (three measurements at two consultations), home (three measurements morning and evening over 3 days) and 24-h ambulatory monitoring. Target organs were evaluated by ECG, echocardiography, carotid echography and detection of microalbuminuria. Data from 302 patients were analyzed.

RESULTS

Mean BP levels were 142/82 mmHg for office, 135.5/77 mmHg for home and 128/76 mmHg for 24-h monitoring (day = 130/78 mmHg; night = 118.5/67 mmHg). With a 135 mmHg cut-off, home and daytime blood pressure diverged in 20% of patients. Ambulatory and Home blood pressure were correlated with organ damage more closely than was office BP with a trend to better correlations with home BP. Using regression analysis, a 140 mmHg home systolic blood pressure corresponded to a 135 mmHg daytime systolic blood pressure; a 133 mmHg daytime ambulatory blood pressure and a 140 mmHg home blood pressure corresponded to the same organ damage cut-offs (Left ventricular mass index = 50 g/m, Cornell.QRS = 2440 mm/ms, carotid intima media thickness = 0.9 mm). Home-ambulatory differences were significantly associated with age and antihypertensive treatment.

CONCLUSION

We showed that home blood pressure was at least as well correlated with target organ damage, as was the ambulatory blood pressure. Home-ambulatory correlation and their correlation with organ damage argue in favor of different cut-offs, that are approximately 5 mmHg higher for systolic home blood pressure.