Healthy living Preprint

Veterans in a home blood pressure program had a lower death rate over six years

Among about 60,000 US veterans with high blood pressure, those enrolled in a program where they measured their blood pressure at home and sent the readings to their care team died about 8% less often over roughly six years than closely matched veterans who were not enrolled. A small rise in heart attacks and strokes largely disappeared once the team corrected for more frequent contact with doctors. The study is observational and a not yet peer-reviewed preprint.

High blood pressure is one of the most common chronic conditions in older age and one of the biggest drivers of heart attacks, strokes and early death. Lowering it reduces those risks. One tool that guidelines recommend, but that is not used much, is measuring blood pressure at home: readings taken at rest in a familiar place can show what pressure really is between doctor's visits.

Randomized controlled trials have shown that home monitoring helps lower blood pressure as measured in the clinic. What nobody had shown, according to the team behind this study, is whether it changes the outcomes that matter most, such as death, when used in everyday care. This new analysis, posted as a not yet peer-reviewed preprint, looked at the US Veterans Health Administration (VHA), which runs a large telehealth program where patients send home readings to their care team.

What they did

The researchers used an approach called target trial emulation: they designed the comparison as if it were a trial, but built it from health records. Veterans were eligible if a primary-care visit between 2013 and 2019 showed a systolic (upper) blood pressure above 140 mmHg, and their pressure had also been high before.

Of more than 2.2 million veterans with such a reading, 30,203 who enrolled in the home monitoring program met all the criteria. Each was matched with a veteran who did not enroll but was similar in age, sex, blood pressure, number of blood pressure drugs, frailty, estimated risk of dying within a year and other health conditions. That gave 30,096 controls. The enrolled veterans were 66.8 years old on average, had an average blood pressure of about 160/86 mmHg and took 2.3 blood pressure drugs.

The median time in the program was 202 days, and follow-up lasted about 6.4 years. The team counted deaths and "major adverse cardiovascular events": non-fatal heart attacks, strokes, sudden heart failure and unstable angina (chest pain from a heart under strain) that ended in an emergency visit or a hospital stay.

What they found

  • Fewer deaths. 32.2% of the home-monitoring group died during follow-up, compared with 33.8% of the controls. After matching, that was an 8.3% lower risk of death (hazard ratio 0.92).
  • Slightly more heart events at first sight. 34.7% of the monitored group had a major cardiovascular event, compared with 33.6% of controls, a 4.1% higher risk.
  • A clue that this was about detection. The team also looked at conditions that blood pressure should not affect: cataracts, earwax blockage, skin inflammation and appendicitis. The monitored veterans had more of these too, which suggests they simply saw doctors more often, so more problems of every kind got recorded. After correcting for this, the extra heart events were no longer statistically significant, while the lower death risk became even larger.
  • Not everyone benefited equally. The lower death risk was seen in most groups, but not in veterans with the lowest starting blood pressure or the lowest estimated risk of dying.

What to keep in mind

  • Not a randomized trial. Veterans were not assigned to the program at random. Matching makes the groups look alike on what was measured, but other differences may remain, including the possibility that healthier, more motivated people joined. The authors think this "healthy user" effect is unlikely to explain everything, because the enrolled group had a high heart risk.
  • The authors' own limitations: few women in the sample, heart events identified from billing codes (which can miss events), no information on team-based care, and not every enrolled veteran actually sent home readings.
  • Program, not device. What was studied is a care program with a team reviewing readings, not buying a monitor on one's own.
  • Not yet peer-reviewed. Other experts have not yet checked the analysis.

Why it matters

Home blood pressure monitoring is cheap and recommended, but proof that it saves lives in routine care has been missing. In a large group of older veterans with poorly controlled blood pressure, enrolling in a home monitoring program was linked to a modestly lower death rate. The authors note that even a small reduction could add up to many lives because high blood pressure is so common. The study also shows how a careful check with unrelated conditions can expose a misleading result.

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