Continued Blood Pressure Monitoring Necessary for Hypertension Control

Karen Margolis, MD

In an effort to further investigate hypertension, the leading cause of cardiovascular disease, investigators followed up with 450 patients with uncontrolled hypertension from a cluster randomized clinical trial evaluating telemedicine on long-term hypertension outcomes.

Notably, the team found that continued monitoring for blood pressure (BP) control is likely required for long-term maintenance, and resumed intervention is likely necessary if BP increases.

“Previous research showed telemonitoring and pharmacist consultation helped patients manage blood pressure for about one year,” Karen Margolis, MD, executive director of research at HealthPartners Institute told MD Magazine^Ò. “Beyond 1 year, though, we did not know whether telemonitoring and pharmacists consultation would provide sustained, long-term benefits.”

The study was designed, Margolis said, to figure out the longer-term implications of this approach to BP. As such, the two-group follow-up conducted from March 2009 to November 2015 randomized participants to either the telemonitoring intervention (228) or usual care (222) among 16 primary care clinics at HealthPartners Medical Group.

Qualification criteria for patients included a BP of 140/90 mm Hg or higher at the 2 most recent primary care encounters in the previous year.

From baseline to the 54-month research clinic, the primary outcome was a change in systolic BP (SBP). Other outcomes measured included changes from baseline to 54 months in diastolic BP (DBP) and the number of antihypertensive medication classes recorded from the medication inventory at each visit. Outcomes from patient surveys included assessments on use of a home BP monitor.

At each research clinic visit, 3 BP measurements were taken at one-minute intervals at 6, 12, 18, and 54 months.

Upon data collection, investigators observed the differential reduction by study group in SBP from baseline to 54 months to be -2.5 mm Hg (95% CI; -6.3 - 1.2). Similarly, the differential reduction by study group in DBP from baseline to 54 months was observed to be -1 mm Hg (95% CI; -3.2 - 1.2).

According to the study authors, the SBP and DBP results suggested significantly lower BP in the intervention group for up to 24 months.

In the intervention group, the number of antihypertensive medication classes showed differentially greater increases compared to the usual care group. With increases of 0.63 (95% CI; 0.46 - 0.79) in the intervention and 0.64 (95% CI; 0.47 - 0.80) in usual care, no differential increase was displayed (P = .92).

At 6 and 12 months in the intervention group, the proportion of patients using a home BP monitor increased markedly; however, the usual group did not. At 18 months, a decline in home BP monitoring in the TI group was observed. At 54 months, no differential long-term increase was observed, with home BP monitoring in the intervention group (59.6%) comparing similarly to the usual care group (50%).

Investigators noted home BP monitors were returned to the monitor at 12 months and were not replaced by the study. In addition, over time in both groups, patients’ belief in their ability to include home BP monitoring in their weekly routine declined.

Investigators also indicated a limitation of the study, which included that about 28% of the original study cohort did not attend the 54-month follow-up visit.

Overall, investigators concluded that no significant differences in SBP or DBP at 54 months are evident with home BP telemonitoring with pharmacist management. This conclusion is primarily related to an increase in BP in the intervention group. However, at 18 months, a significant difference in SBP was recorded.

Additionally, an intervention effect may continue for up to 24 months—12 months after the end of the intervention—according to the BP documented in the electronic health record (HER).

“We are building upon this research by conducting a similar trial in a real-world primary care setting,” Margolis added, “which should tell us whether and to what extent this intervention is beneficial for the broad population of patients seeking medical care.”

The study, "Long-term Outcomes of the Effects of Home Blood Pressure Telemonitoring and Pharmacist Management on Blood Pressure Among Adults With Uncontrolled Hypertension," was published in JAMA Open on Friday.