EHRA 2021: The STROKESTOP-Study
In many patients, atrial fibrillation (AF) remains undetected, leaving them with an increased risk of ischaemic stroke (up to 5-fold) and death (up to 3-fold). Now there is an evidence showing an early detection of AF, through screening and subsequent initiation of treatment with oral anticoagulation (OAC) could substantially reduce the risk of these adverse events, without leading to an excess bleeding risk. This is according to the breakthrough findings from the STROKESTOP trial, presented online at 2021 European Heart Rhythm Association congress (EHRA).
The trial was a population-based systematic screening study that included approximately 14,000 individuals aged 75-76 (mean age 76, 55% women) and residents of two different regions in Sweden. According to the study’s presenting author, Emma Svennberg MD, PhD (Karolinska Institutet, Stockholm, Sweden), “this was a very pragmatic study” with no exclusion criteria. The individuals were randomised in a one-to-one fashion to the screening or control groups. In the screening group, individuals with no prior AF were asked to do an intermittent ECG at home, twice daily for two weeks. A systematic follow-up was then arranged for the individuals with newly diagnosed AF and those with pre-existing AF who were not taking OAC drugs.
There was no loss of follow-up during minimum of 5.6 years. “After our screening intervention, the diagnosis of AF became significantly more common as compared to the control group” Svennberg stated. With regard to the primary combined endpoint (ischaemic stroke or systemic thromboembolism, all-cause mortality, haemorrhagic stroke, and severe bleeding), the patients in the screening group experienced fewer events than those in the control group (4456 vs. 4616 events respectively, HR 0.96: CI 0.920-0.999; p-value=0.045). “The hazard ratio was small but significant” Svennberg said, adding that “we needed to invite 91 individuals in order to prevent one event”.
Looking at the participants invited for screening, only half (51%) did in fact participate in the screening intervention. These individuals, compared to the non-participants, were younger, less dependent on OACs and overall healthier with fewer co-existing comorbidities (i.e. ischaemic stroke, heart failure, hypertension, vascular disease and diabetes), and smaller CHA₂DS₂-VASc score (3.3 vs 3.7 respectively; all p-values <0.001). According to the results of ‘as treated’ analysis, the screened participants did significantly better in terms of pre-specified secondary endpoint of ischaemic stroke (HR 0.76; 95% CI 0.68-0.87), but one should bear in mind that they were also already healthier than those who didn’t participate in the screening.
With the observation of a net clinical benefit of screening firmly insight, “efforts should be made to increase participation in atrial fibrillation screening” as the risk of adverse events remains high among the non-screened elderly population.