Does Telemonitoring Blood Pressure Help Time to Detection of Gestational Hypertension?

Richard J. McManus, MBBS, PhD

Self-monitoring for elevated blood pressure via telemonitoring did not lead to earlier clinic-based detection of hypertension among pregnant individuals, but did not show harm linked to self-monitoring or safety issues, either, according to an original investigation published in JAMA.

Investigators from the University of Oxford conducted a randomized clinical trial of 2,441 pregnant individuals in order to determine if those that self-monitor blood pressure in high-risk pregnancies have earlier detection of pregnancy hypertension.

The pregnant participants were at a higher risk of preeclampsia and recruited at an average of 20 weeks’ gestation from 15 hospital maternity units in England between November 2018 and October 2019. The participants were divided into 2 groups and were either assigned to self-monitor blood pressure with telemonitoring plus usual care or usual antenatal care alone, without telemonitored blood pressure, the investigators explained.

Study data show the mean age of the participants was 33 years and while 18 series adverse events were reported during the trial, none were deemed related to the intervention. The participants in each group were well matched for demographic characteristics and risk factors for hypertension and preeclampsia.

The investigators defined clinic-hypertension as sustained blood pressure of 140/90 mm Hg or greater when recorded by a health care professional in a clinical record in any setting leading up to the day before delivery. Sustained hypertension was defined as having ≥2 elevated blood pressure readings within a week, the study authors wrote.

Notably, before they were randomized, 639 participants (27%) reported previously measuring their own blood pressure; they made up 25% of the self-monitoring group and 28% of the usual care group post-randomization.

The study authors observed clinic hypertension recorded for 179 participants in the intervention group and 184 participants in the usual care group. There were 102 participants overall with preeclampsia, or 4%.

“The most surprising thing was that despite this, over half of participants who self-monitored and developed high blood pressure did measure raised blood pressure at home before it was detected in the clinic, on average about one month earlier,” study author Richard J. McManus, MBBS, PhD told HCPLive®.

However, there was no significant difference in time to clinic hypertension being recorded between individuals who self-monitored or received usual care alone, the study authors wrote. This finding persisted even when the investigators adjusted for missing data, multiple imputation, or when more narrow definitions of clinic hypertension, such as a recorded diagnosis of gestational hypertension or a prescription for antihypertension medication alone, were excluded.

“The results showed no earlier diagnosis of high blood pressure with self-monitoring and telemonitoring, but importantly did not show any harm associated with self-monitoring or safety issues,” McManus continued. “We know that at least 1 in 5 people who are pregnant in the UK are already self-monitoring their own blood pressure and these results should not stop them from doing so.”

The study authors additionally said there was no statistically significant difference in the incidence of severe hypertension or in the incidence of preeclampsia between the 2 groups.

“While the trial did not show an overall benefit in earlier clinic-based diagnosis, further research could assess whether the earlier raised blood pressure observed at home in some women might mean that different protocols for home monitoring are associated with new benefits,” McManus concluded, while noting that several other trials aimed at obtaining additional information on this topic are already underway.

The study, "Effect of Self-monitoring of Blood Pressure on Diagnosis of Hypertension During Higher-Risk Pregnancy: The BUMP 1 Randomized Clinical Trial," was published in JAMA.