A Successful Multifaceted Trial to Improve Hypertension Control in Primary Care: Why Did it Work?

Abstract

BACKGROUND: It is important to understand which components of successful multifaceted interventions are responsible for study outcomes, since some components may be more important contributors to the intervention effect than others. OBJECTIVE: We conducted a mediation analysis to determine which of seven factors had the greatest effect on change in systolic blood pressure (BP) after 6 months in a trial to improve hypertension control. DESIGN: The study was a preplanned secondary analysis of a cluster-randomized clinical trial. Eight clinics in an integrated health system were randomized to provide usual care to their patients (n=222), and eight were randomized to provide a telemonitoring intervention (n=228). PARTICIPANTS: Four hundred three of 450 trial participants completing the 6-month follow-up visit were included. INTERVENTIONS: Intervention group participants received home BP telemonitors and transmitted measurements to pharmacists, who adjusted medications and provided advice to improve adherence to medications and lifestyle modification via telephone visits. MAIN MEASURES: Path analytic models estimated indirect effects of the seven potential mediators of intervention effect (defined as the difference between the intervention and usual care groups in change in systolic BP from baseline to 6 months). The potential mediators were change in home BP monitor use, number of BP medication classes, adherence to BP medications, physical activity, salt intake, alcohol use, and weight. KEY RESULTS: The difference in change in systolic BP was 11.3 mmHg. The multivariable mediation model explained 47 % (5.3 mmHg) of the intervention effect. Nearly all of this was mediated by two factors: an increase in medication treatment intensity (24 %) and increased home BP monitor use (19 %). The other five factors were not significant mediators, although medication adherence and salt intake improved more in the intervention group than in the usual care group. CONCLUSIONS: Most of the explained intervention effect was attributable to the combination of self-monitoring and medication intensification. High adherence at baseline and the relatively low intensity of resources directed toward lifestyle change may explain why these factors did not contribute to the improvement in BP.

Long-term Outcomes of the Effects of Home Blood Pressure Telemonitoring and Pharmacist Management on Blood Pressure Among Adults With Uncontrolled Hypertension

“…The study design and methods are described in detail in the Supplement and in previous reports, 15,18,19,20,21,22 and recruitment, enrollment, and follow-up of the study cohort are shown in Figure 1. Briefly, we used electronic data to identify individuals and mail recruitment letters between March 2009 and April 2011 to 14 492 adult patients who had BP of 140/90 mm Hg or higher at the 2 most recent primary care encounters in the previous year.…”

Short-term telemedical home blood pressure monitoring does not improve blood pressure in uncomplicated hypertensive patients

“…Especially, studies with a long follow-up have shown effect on blood pressure, like the HyperLink study using a multifaceted approach in a cluster randomized design. 18 After 12 months they found a 11.3-mm Hg systolic difference in blood pressure reduction. After 6 months another primary-care study found a mean difference in daytime ABPM of 4.3 mm Hg systolic and 2.3 mm Hg diastolic.…”

A substudy evaluating treatment intensification on medication adherence among hypertensive patients receiving home blood pressure telemonitoring and pharmacist management

“…Paul, MN, metropolitan area that is part of an integrated health system. Study recruitment, enrolment and outcomes from the HyperLink trial are described previously . In the HyperLink trial, 2020 patients were screened and 450 were identified as eligible and volunteered to participate.…”

“…Self‐reported medication adherence improved more in the TI group compared with UC; however, it was not a significant mediator of the greater blood pressure lowering in the TI group. One potential explanation is the high rate of medication adherence at baseline may have left little room for further improvement . Another possibility is that measurement error inherent in self‐reported adherence made it difficult to discern any improvement.…”