STROKESTOP: Benefits of systematic screening for atrial fibrillation

Population-based screening of over 28,000 elderly Swedish individuals for atrial fibrillation (AF) reduced the risk of ischaemic and haemorrhagic stroke, systemic embolism, and death, leading to a net clinical benefit in this population [1].

Patients with AF have a 5-fold increased risk of ischaemic stroke, and 10% of stroke patients have undetected AF, leading to a 1.5-3-fold increased risk of death. The risk of stroke and death can be reduced by 65% and 26%, respectively, when AF is diagnosed and patients receive treatment with oral anticoagulants [1].

The STROKESTOP study (NCT01593553) aimed to evaluate whether early detection and treatment of AF can reduce the risk of ischaemic stroke and death without excess risk of bleeding. All residents aged 75 and 76 years in two Swedish regions were identified and randomised 1:1 into a screening group (n=13,979) and a control group (n=13,996), without any applicable exclusion criteria. Screening intervention was single ECG twice daily for 14 days in individuals without history of AF. If AF was detected or there was prior AF without anticoagulant treatment, a systematic follow-up was initiated. From the 13,979 subjects invited to screening, 7,165 (51.3%) participated in the study. The control group was followed up for a minimum of 5.6 years without any loss. Patient characteristics with regards to age, gender, and medical history (e.g. diabetes, cardiovascular diseases)were well balanced between screening and control groups. However, there were significant differences between participants and non-participants in screening, with subjects participating in the screening having significantly fewer comorbidities (e.g. heart failure 4.8% vs 10.3%, stroke, or embolism 8.8% vs 13.5%, hypertension 31.6% vs 39.6%, diabetes 11.6% vs 18.9%; all P<0.001) [1].

Subjects without a history of AF who were invited for screening were examined via single lead ECG twice a day for 14 days. Subjects in which AF was detected and subjects with prior AF but without anticoagulant treatment were followed up systematically.

AF was significantly more often diagnosed in subjects participating in the screening than in controls (P=0.005). Final results from the primary endpoint showed a small but statistically significantly favourable outcome in the screening arm with 4,456 incidences compared with 4,616 in the control arm (P=0.045; see Figure). Ninety-one invited individuals were required to prevent 1 event.

Figure: AF screening resulted in a lower risk of death and benefits of screening slowly increased over time [1]

Dr Emma Svennberg (Karolinska Institute, Denderyd Hospital, Sweden) concluded that population-based screening for AF provided a net clinical benefit in an elderly population. The presented study was one of the first to evaluate the benefits of systematic screening. Efforts must be made to increase participation in AF screening as non-participants were at the highest risk of adverse events. STROKESTOP 2 will look further into potential socio-economic factors influencing participation in screening examinations.

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   1. Svennberg E, et al. Benefits of systematic screening for atrial fibrillation – the STROKESTOP study. EHRA 2021 Congress, 23-25 April.

 

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Posted on 16 June 202122 June 2021