Self-monitoring of Blood Pressure in Primary Care

Hypertension is a major risk factor for renal and cardiovascular disease (CVD). While the health benefits of lowering blood pressure (BP) are well documented, population surveys have consistently found that less than a quarter of hypertensive patients have their BP under good control. Self-monitoring of BP at home has been extensively evaluated as a potentially useful tool to improve BP control and medication adherence in hypertensive patients.

We developed a user-centric home BP tele-management system. The system captures all home self-measured BP readings and requires patients to set jointly with their physician their BP treatment goal, home BP monitoring schedule and BP alert levels. The system tracks the frequency, date and time of home readings, generates messages for patients and reports for physicians indicating whether the BP treatment goal has been reached, and sends BP alerts and adherence reminders for BP readings to patients and clinical BP alerts and reports to physicians. Using an open, randomized controlled parallel group trial design, older diabetic patients with uncontrolled systolic hypertension, recruited from the practice of primary care physicians, will receive either usual care approach to home BP monitoring or care that incorporates the use of the home BP tele-management system. The primary outcome measure is the change in mean daytime systolic BP from baseline to the last (12-month) visit on 24-hour ambulatory. The secondary objective is to examine the psychosocial factors that may make it difficult for some patients to monitor their blood pressure at home. The rationale for including a psychological component in the study is that a critical component of the system is adherence to self-monitoring. While adherence can be automatically determined through the telemanagement system, the determinants of adherence to this behaviour have not been adequately assessed in the literature. To gain insights into this aspect of health behaviour we will measure psychological predictors using quantitative and qualitative techniques. Moreover, monitoring adherence with home BP monitoring will provide a proxy measure of acceptance of the system as a poor adherence rate would suggest that patients perceive it as a futile exercise, not leading to any changes in their care.

This study tests a novel approach to treat hypertension, a major health problem in diabetic patients. The information from this study will be invaluable for future health care planning.

Inclusion criteria

• Diagnosis of type 2 diabetes mellitus (the onset of diabetes must have occurred on or after the age of 30 years and there is no history of diabetic ketoacidosis)
• Uncontrolled systolic hypertension (defined as a daytime systolic BP of 130 mm Hg or higher on 24-hour ambulatory)

Exclusion criteria

• Conditions making the patient unsuitable for study such as severe cognitive impairment, language difficulties (unable to speak and understand instructions in English), frequent (more than once per month for more than week) or prolonged (more than 2 months) trips away from home, homelessness, self-identified substance abuse, being pregnant, or unable to use home BP device;
• Life expectancy less than one year
• Coexisting conditions that require frequent (more than once a month) office visits or repeated (more than once in the past year) hospitalizations
• Atrial fibrillation or other cardiac arrhythmias requiring drug treatment
• Moderately severe chronic renal failure defined as estimated GFR less than 25 mL/min
• Myocardial infarction, episode of heart failure requiring hospitalization, or paralyzing stroke in the past year
• Having unstable angina
• Severe valvular heart diseases such as severe aortic stenosis
• Symptomatic orthostatic hypotension
• Refusal to sign consent form or to carry out the demands made by the study