The association between adherence to a systematic atrial fibrillation screening program and clinical outcomes: a subanalysis from the STROKESTOP study

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: Other. Main funding source(s): Stockholm County Council, the Swedish Heart & Lung Foundation INTRODUCTION: Screening for atrial fibrillation (AF) in older adults and high-risk patients may be beneficial in preventing clinical outcomes such as stroke. Studies on clinical outcomes in screening-detected AF have highlighted difficulties in getting the population at highest risk to participate in screening programs. Whether the risk of clinical outcomes differs among individuals depending on the level of adherence to the screening program instructions, is currently unknown. PURPOSE: To explore associations between different levels of adherence consistency of and adherence to systematic screening, consisting of measurements using a handheld ECG device, and clinical outcomes. METHODS: Half of all 75- and 76-year old inhabitants of two Swedish regions were invited to participate in an AF screening program (STROKESTOP I study). Participants in whom AF was not diagnosed previously or during the baseline visit, were asked to perform 30-seconds recordings using a handheld ECG device twice daily for a period of two weeks. The total screening period consisted of 13 days. Adherence was defined as the total number of recordings performed divided by the total number of recordings asked, whereas adherence consistency was defined as the number of screening days on which the asked number of recordings was performed. Based on the thresholds when 90% of AF cases were detected, the participants were divided into low (<73%), moderate (73-99%) and optimal (≥100%) adherence and low (10 days), moderate (11-12 days) and optimal (13 days) adherence consistency groups. RESULTS: In total, 6436 participants (3585 females (55.7%)) were included in the analysis. Participants with low adherence consistency were at higher risk of ischemic stroke (hazard ratio (HR) 1.7 (95% confidence interval (CI) 1.2-2.3), p=0.001), systemic embolism (HR 1.7 (1.3-2.4), p=<0.001), dementia (HR 1.7 (1.3-2.2), p<0.001), and a composite endpoint of stroke, systemic embolism, bleeding leading to hospitalisation, and all-cause death (HR 1.3 (1.1-1.5), p=0.001), as well as the composite endpoint with the addition of cardiovascular hospitalisation (HR 1.2 (1.1-1.4), p=0.001) compared to patients in the optimal group (Figure 1). In addition, participants with low adherence were at higher risk of the composite endpoint with cardiovascular hospitalisation (HR 1.3 (1.0-1.7), p=0.018), as well as of the individual endpoints dementia (HR 2.5 (1.7-3.6), p<0.001) and cardiovascular death (HR 2.1 (1.3-3.6), p=0.004). CONCLUSION: Low adherence and adherence consistency in systematic screening for AF were associated with a higher risk of adverse cardiovascular and cerebral outcomes. [Figure: see text]