US-based digital healthcare company iRhythm Technologies has unveiled the results from the GUARD-AF clinical trial of its Zio XT patch ECG long-term continuous monitoring (LTCM) monitor.
The results of the study, which was sponsored by a collaboration between Bristol-Myers Squibb and Pfizer, were presented at the European Society of Cardiology (ESC) Congress 2024.
GUARD-AF was designed to test whether the on-label Zio XT 14-day single-lead LTCM could identify patients, aged 70 years and above, with undiagnosed AF and reduce stroke.
The study enrolled 11,905 patients from 149 primary care sites in the US, and the participants were randomised 1:1 to undergo screening with Zio XT LTCM or usual care.
Its primary efficacy and safety outcomes include hospitalisation due to all-cause stroke and bleeding, respectively.
During a median follow-up of 15 months, Zio XT LTCM led to an increase in new diagnoses of AF compared to usual care through the end of follow-up.
The study results were presented by Duke University, and Duke Clinical Research Institute professor Renato Lopes, at the ESC Congress.
Lopes said: “Owing in part to the low event rate and truncated enrollment, the study found no reduction in the rate of stroke.
“However, there are some important lessons here. Our study confirms that AFib is common in older patients and can be identified with cardiac monitoring in primary care.
“Most participants with AFib also had short, infrequent episodes that would be missed with a pulse check, single ECG, and shorter duration of monitoring.
“Identification of these short episodes could be a useful prompt for physicians to more aggressively treat heart disease risk factors and may reduce the downstream risk of heart failure, which will be evaluated in future trials.”
The GUARD-AF study showed that screening with Zio XT LTCM led to an increase in the diagnosis of AF compared to usual care.
It is the largest randomised trial to evaluate the impact of AF screening with a patch-based ECG monitor in a primary care setting, in which more than half participants enrolled were women.
The study validated the feasibility of primary care-initiated home-based monitoring in an older population, along with virtual, home-based diagnostics.
Furthermore, the GUARD-AF study underscores how large clinical trials powered by the Zio LTCM service are feasible at scale, said iRhythm.
iRhythm chief medical and scientific officer and product innovation EVP Mintu Turakhia said: “These findings support the totality of evidence that undiagnosed AFib is common and can be found with Zio’s 14-day long-term monitoring.
“iRhythm’s undiagnosed arrhythmia pilot programs leverage many features seen in GUARD-AF, such as virtual enrollment and self-applied patches at home.
“These programmes, as well as ongoing clinical trials, such as AMALFI6, and those in development will have longer follow-up or assess a wider range of outcomes, including heart failure, which occurs in one-third of patients with AFib.”
