Measuring Adherence to Control Hypertension

Despite the presence of numerous effective medications, one-half of the adults receiving treatment for hypertension in the United States have uncontrolled blood pressure. At least one-third of these hypertensive patients are not adherent to their blood pressure medications. Given this high rate of non-adherence, clinicians will ideally consider whether their patients are taking their pills before deciding whether to intensify a blood pressure regimen. Yet, in practice, clinicians are often unsure about their patients' level of adherence. This uncertainty limits clinicians' ability to optimally manage hypertension. Electronic medication monitors represent the gold-standard for objectively measuring day-to-day adherence. As a result, they have the potential to best reduce uncertainty regarding medication adherence. The goal of this study is to test whether providing clinicians with an objective measure of medication adherence obtained through electronic monitoring can improve clinician management of uncontrolled hypertension. When data from monitoring indicate poor adherence, it may motivate clinicians to counsel their patients on adherence. Conversely, when data from monitoring indicate good adherence among patients with uncontrolled hypertension, it may motivate clinicians to intensify treatment rather than presume patients were non-adherent.

To test this hypothesis, this study will first enroll and randomize 30 primary care clinicians. Clinicians randomized to the intervention will be trained in the use of a quantitative report that summarizes their patients' adherence to blood pressure medications; they will receive these reports during visits with patients who later get enrolled in the study.

The study will then enroll 300 patients with uncontrolled hypertension from the same clinic. These patients will then have their adherence to up to 4 blood pressure medications measured by an electronic pillbox. The MedSignals® pillbox (LIFETECHniques Inc., San Antonio, TX) is small (5"x3½"x1"), easily portable, and can simultaneous monitor adherence to up to four medications. The device records a pill as taken each time the individual pillbox lid is opened and closed. Data on adherence are easily uploaded (< 1 minute) by connecting the pillbox to a telephone line.

Patients will return to the clinic after 1 month of taking their pills from the electronic pillbox for a visit with a research assistant and their clinician. At this time, data from the pillboxes will be downloaded and used to generate an adherence report. The report will summarize the percent of days that blood pressure medications were taken as prescribed during the monitoring period and will provide guidance on how to take action based on the data. After the report is generated (< 5 minutes), patients will attend visits with their clinicians. Clinicians in the intervention group will receive the adherence report at the time of this visit whereas clinicians in the control group will treat patients according to usual care (without report). Hypertension management during the 1-month clinic visit will be assessed after the visit by 1) reviewing the medical note to determine if clinicians intensified hypertension treatment and 2) surveying patients to determine if clinicians counseled them on adherence. Hypertension management will then be compared between groups.

Inclusion criteria

• established diagnosis of hypertension
• prescribed at least one blood pressure (BP) medication
• at least two consecutive clinic visits with elevated BP according to Joint National Committee (JNC-7) guidelines (i.e., BP ≥ 140/90 mmHg or ≥ 130/80 mmHg if diabetes or chronic kidney disease)
• 18 to 80 years old
• at least one prior visit with a clinician enrolled in the study

Exclusion criteria

• severe mental illness
• resided in a long-term care facility
• unable to use the electronic adherence device due to physical or cognitive impairment
• non-English or non-Spanish speaking
• unavailable for follow-up