Further efforts should be made to increase participation in atrial fibrillation (AF) screening—particularly in elderly populations, where systematic screening for AF can help to lower the risk of adverse events and reduce comorbidities. This is according to a late-breaking presentation of clinical trial data at the 2021 European Heart Rhythm Association congress (EHRA, 23–25 April, online).
The STROKESTOP trial, which involved randomising close to 28,000 patients aged 75–76 into a screening group and a control group, found “significantly fewer” events like ischaemic stroke, all-cause mortality and severe bleeding at five years in those who chose to undergo interventional screening for AF via intermittent electrocardiogram (ECG) recordings compared to those who chose not to participate.
Emma Svennberg, the study’s presenting author and a cardiologist at Karolinska University Hospital (Stockholm, Sweden), said: “With regards to clinical characteristics, the groups were well-balanced and there were no significant differences between them. However, if we look at the group of patients randomised to screening, we can see that those choosing to participate in our screening intervention had significantly fewer comorbidities when compared to the non-participants.”
According to Svennberg, AF increases the risk of ischaemic stroke, and ultimately death, but can also be asymptomatic and remains undetected in about 10% of stroke patients. Furthermore, because the oral anticoagulants often used to treat the condition can increase bleeding risks for patients, the study’s researchers set out to determine whether early detection and treatment of AF can reduce the risk of ischaemic stroke and death without leading to an excess bleeding risk.
The trial involved patients aged 75–76 living in two regions of Sweden and featured no other exclusion criteria. From a pool of about 28,000 patients, Svennberg said 13,979 were invited for screening, while 13,996 were randomised into the trial’s control group. All of these patients were then followed for a minimum of five years. In the group invited to undergo screening, 7,165 (51.3%) chose to participate, while 6,814 (48.7%) chose not to. The trial’s primary combined endpoint included ischaemic stroke or systemic thromboembolism, all-cause mortality, haemorrhagic stroke, and hospitalisation due to bleeding.
At the end of the trial, Svennberg stated that AF diagnoses became “significantly more common” in the screening group, but remained roughly the same in the control group. The screening group also saw 4,456 adverse events relating to the trial’s primary combined endpoint compared to the 4,616 events observed in the control group. This resulted in a hazard ratio of 0.96, which Svennberg described as indicating a “small, but significant difference” between the two.
However, solely within the group randomised to receive screening, those who chose to participate experienced fewer comorbidities—including ischaemic stroke, heart failure, hypertension and diabetes—and also required oral anticoagulants less often.
“Looking at our prespecified secondary endpoint, the as-treated analysis, we could see that those choosing to participate in our screening study had a significantly lower risk of ischaemic stroke,” Svennberg added, also noting the consideration that those who opted to participate were more healthy overall compared to the non-participants.
These results led the study’s researchers to conclude that population-based AF screening provides a net clinical benefit in elderly populations, and efforts should be made to increase participation in screening interventions, as non-participants were found to be at the highest risk of adverse events.
In a discussion following the presentation, Renate Schnabel, an interventional cardiologist and professor in cardiology at University Heart Center Hamburg (Hamburg, Germany), noted that the STROKESTOP trial is “one of the first studies, if not the first study, to show a benefit of screening for a common cardiovascular disease—atrial fibrillation”.
“What we need now is cost-effectiveness analysis, which will definitely follow,” she added. “This study provides sound information for cost-effectiveness analyses, which, to date, have largely relied upon assumptions.
“We will also need to see whether large-scale, systematic screening approaches, such as in the STROKESTOP study, are bypassed by increasingly common, consumer-led screening through wearables and apps—even in older populations.
“But, for now, the future guidelines have gained strong evidence on which to judge systematic AF screening by a prolonged, intermittent handheld device. How to implement AF screening, including systematic screening in healthcare systems across Europe and beyond, remains an open question. The investigators will dive deeper into their study data, and many fruitful discussions will follow, advancing the field of AF research.”