The impact of long-term blood pressure (BP) telemonitoring on the incidence of cardiovascular events during the COVID-19 pandemic: a records based, matched patient analysis

It is well established from trials that BP telemonitoring leads to improved BP control. However, there is little data available on the impact of BP telemonitoring on the incidence of cardiovascular events when it is used as the routine mode of long term BP monitoring,

This study aimed to explore the impact of Blood Pressure (BP) telemonitoring on clinical cardiovascular outcomes, including during the covid-19 pandemic when the service was being provided with little face to face support.

Records were analysed for 442097 adults with hypertension identified from prescribing records from 5 Scottish Health Boards.

Patients were included in they had a prescription for a first line anti-hypertensive drug at any time from 1 March 2019 (1 year before the first cases of COVID-19 were identified in Scotland) and 28 February 2021. Follow up was until 1st March 2022. Women pregnant during that time were excluded.

The primary outcome measure was emergency hospital admission for Acute Coronary Syndrome (ACS), Stroke or uncontrolled Heart Failure (HF). Outcomes were compared between people who had used BP telemonitoring for at least 1 year and a matched group who had not used it at all. Matching was on age, sex, ethnicity, social deprivation, number of anti-hypertensive drugs, diabetes and having a BP assessment in the same year.

Ninety percent of the cohort had been diagnosed with hypertension before March 2019, 7% between March 2019 and February 2020 and only 3% in the first year of the covid-19 pandemic.

There was a rapid increase in the uptake of BP telemonitoring after the start of the covid-19 pandemic. Those who used telemonitoring were significantly younger, less likely to have diabetes and take less antihypertensive medication. For those who used telemonitoring for over 1 year a mean reduction in systolic BP was seen which was maintained for at least the remainder of the year.

In the matched group analysis people who used telemonitoring were less likely than those who were not to be admitted to hospital with or die from ACS, stroke or uncontrolled heart failure (adjusted OR 0.498 (95% CI 0.336 to 0.739), p=0.001), or to die through any cause (adjusted OR 0.484 (95% CI 0.268 to 0.875), p=0.016), p=0.018) or be admitted to hospital for any cause (adjusted OR 0.713 (95% CI 0.629 to 0.809), p<0.001).

The strength of this study is that, for the first time, enough people were using BP telemonitoring as a long term routine service for the effect on clinical outcomes to be measured. It demonstrated that the reduction in systolic BP achieved at the start of telemonitoring was maintained and was associated with a significant reduction in cardiovascular events. However the study took place at a time of service disruption and longer term evaluation, with access to BP records for those not using telemonitoring, is needed.