PHILADELPHIA – A home blood pressure telemonitoring program featuring pharmacist management of patients with uncontrolled hypertension reduced cardiovascular events by half and was cost saving over the course of 5 years, even though the intervention ended after year 1, , reported at the American Heart Association scientific sessions.
“The return on investment was 126%. That means that for every dollar spent on the intervention, that dollar was recouped by $1.00 plus another $1.26,” explained Dr. Margolis, a general internist who serves as executive director for research at the HealthPartners Institute in Bloomington, Minn., and professor of medicine at the University of Minnesota, Minneapolis.
She presented 5-year follow-up data from the(Home Blood Pressure Telemonitoring and Case Management to Control Hypertension) study, a cluster randomized controlled trial involving 16 primary care clinics. Half of the clinics were randomized to the intervention, which entailed home blood pressure telemonitoring and pharmacist-led case management in collaboration with the primary care team. The other eight clinics provided usual care. The intervention portion of the trial, which lasted for 12 months, included 450 adults with uncontrolled hypertension as defined by repeated on-treatment blood pressure readings of 140/90 mm Hg or more. Participants’ baseline mean blood pressure was 148/85 mm Hg while on an average of one and a half antihypertensive drug classes. On average, pharmacists ended up adding one additional drug from a different antihypertensive drug class to achieve improved blood pressure control.
The details of the intervention and the short-term blood pressure results have previously been reported (). Briefly, 6 months into the study, patients in the intervention arm averaged 11/6 mm Hg lower blood pressure than did the usual care controls. At 12 months – when the intervention ended – the between-group difference was similar at 10/5 mm Hg. At 18 months, the difference, while attenuated, remained significant at 7/3 mm Hg in favor of the intervention group. However, at 54 months, the intervention group’s advantage – a 3–mm Hg lower SBP and a 1–mm Hg lower DBP than in controls – was no longer significant.
The exciting new findings Dr. Margolis presented at the AHA scientific sessions focused on 5-year outcomes. Since HealthPartners is an integrated health care system, follow-up was essentially complete.
“None of the other telemetry studies I’m aware of have published anything on cardiovascular events. And we were somewhat surprised when we looked at our data to see fairly substantial differences in our primary outcome,” she noted.
That outcome was a composite of MI, stroke, heart failure, or cardiovascular death occurring over 5 years. The rate was 4.4% in the intervention group and nearly double at 8.6% in controls. That translated to a 51% relative risk reduction. The biggest difference was in stroke: 4 cases in the intervention arm, 12 in usual care controls.
The 5-year coronary revascularization rate was 5.3% in the intervention arm and 10.4% in controls, for a 52% relative risk reduction.
A major caveat regarding the Hyperlink trial was that, even at 450 patients and 5 years of follow-up, the study was underpowered to show significant differences in event rates, with P =.09 for the primary endpoint.
That being said, the financial results were striking. The intervention cost $1,511 per patient in 2017 U.S. dollars. The cost of treatment for major adverse cardiovascular events totaled $758,000 in the intervention group and $1,538,000 in usual care controls. That works out to $3,420 less per patient in the intervention arm. Offset by the cost of the intervention, that spells a net savings of $1,908 per patient achieved by implementing the year-long intervention. It’s a rare instance in health care of an intervention that actually makes money.
These results were unusual enough that Dr. Margolis and her coinvestigators decided to feed their wealth of SBP readings into a microsimulation model, which they ran 1,000 times. The model predicted – in light of the fact that patients in the intervention group were on average 2 years older than the controls were – that the expected reduction in the primary endpoint was 12% rather than the observed 51% relative risk reduction.
How to explain the discrepancy? The Hyperlink results could have been due to chance. Or it could be, Dr. Margolis surmised, that the pharmacists helped accomplish improvements in other cardiovascular risk factors, such as hyperlipidemia, smoking, or sedentary behavior. That’s unknown, since the investigators focused on changes in blood pressure only. Future studies of home telemonitoring and pharmacist case management of uncontrolled hypertension should be powered to detect significant differences in cardiovascular events and should track additional risk factors, she concluded.
She reported having no financial conflicts regarding the study.
SOURCE: Margolis KL. AHA 2019.