A randomized controlled trial comparing remote blood pressure monitoring with office-based blood pressure monitoring for women at high risk of preeclampsia

BACKGROUND: Women at a high risk of developing preeclampsia are recommended to have additional blood pressure surveillance, but frequent outpatient attendances are demanding for patients and the healthcare system. It is unclear whether remote blood pressure monitoring can replace conventional office-based monitoring and improve healthcare utilization without increasing the signal for harm. OBJECTIVE: To evaluate the effects of substituting clinic blood pressure monitoring with remote blood pressure monitoring on fetal and maternal outcomes, and healthcare utilization, in pregnant women at a high risk of developing preeclampsia. STUDY DESIGN: Unblinded, noninferiority, multicenter randomized controlled trial, with recruitment between July 2022 and February 2024 from 3 metropolitan hospitals in Australia. Participants were pregnant women at a high risk of developing preeclampsia based on clinical risk factors or combined first-trimester screening tests, who are routinely referred to a specialist hypertension service for extra blood pressure surveillance, in addition to standard antenatal care. Women randomized to usual care attended these specialist hypertension clinics in-person, with frequency of appointments dictated by clinical need. Women randomized to remote blood pressure monitoring, in addition to receiving routine antenatal care, measured their own blood pressure using an automated blood pressure machine with data transmitted via a smartphone application for specialist review. The primary outcome was a perinatal composite of adverse events of at least one of perinatal loss, high-level neonatal care for more than 48 hours, or a small-for-gestational age baby (<10th centile for fetal weight). The primary outcome was assessed in the intention-to-treat population. The trial was prospectively registered with the Australian and New Zealand Clinical Trials Registry (ACTRN12620001049965p). RESULTS: 270 women were included in the final analysis (intervention n=132, usual care n=138; mean age 34 years, 60.4% from a self-reported non-Caucasian ethnic group). There was no difference in the primary outcome (hazard ratio, 1.0; 95% confidence interval, 0.57-1.76; P=.99). There was also no difference in secondary fetal and maternal outcomes. The intervention group had less total antenatal attendances (median interquartile range, 14 10-17) compared to usual care (16 13-20; P<.01) and less planned outpatient appointments (median interquartile range, 10 8-12 vs 13 10-16; P<.01), without an associated increase in unscheduled hospital presentations. Women undertaking remote blood pressure monitoring were less likely to be admitted to hospital for any cause (hazard ratio, 0.54; 95% confidence interval, 0.30-0.97; P=.04) and specifically for hypertension (hazard ratio, 0.41; 95% confidence interval, 0.19-0.88; P=.02). More antihypertensive prescriptions filled per patient in the intervention arm compared to usual care (median interquartile range, 5 3-9 vs 3 2-5; P<.01). CONCLUSION: Compared to usual care, remote blood pressure monitoring reduced antenatal outpatient appointments and the likelihood of inpatient admissions, without increasing adverse fetal and maternal outcomes. Women undertaking remote monitoring were also more likely to fill antihypertensive medication scripts.