Factors predicting participation and potential yield of screening-detected disease among non-participants in a Swedish population-based atrial fibrillation screening study.

BACKGROUND: The success of any screening program is dependent on participation. The characteristics of participants vs. non-participants have been studied and non-participants usually have a higher risk of disease. The potential yield of screening-detected disease in non-participants could be of interest to several screening programs. AIMS: This is a sub-study to STROKESTOP II, a Swedish atrial fibrillation screening study. The aim was to study factors predicting participation and to estimate the potential yield of screening-detected disease in non-participants. METHODS: Individual, anonymized data for participants and non-participants with respect to socioeconomic factors, medical history and drugs dispensed were obtained from Swedish registries. A random forest model was trained to predict propensity scores for participation. The propensity scores were used to estimate potential screening-detected disease among non-participants. RESULTS: Non-participants (n = 7086) had lower income, were more likely to have been hospitalized and had higher CHA2DS2-VASc scores compared to participants (n = 6868). The strongest factor predicting non-attendance was low income. The weighted estimates suggested that the yield of new atrial fibrillation was 2.4% in non-participants compared to 2.3% in the participants, which was not significant. CONCLUSIONS: Non-participants had higher CHA2DS2-VASc scores, indicating a higher stroke-risk and presumable benefit from attending screening, although estimated new atrial fibrillation detected was not significantly more common when compared to participants. Low income was the strongest factor for predicting non-attendance and should be a focus area when planning future screening scenarios.

Performance of pulse palpation compared to one-lead ECG in atrial fibrillation screening.

BACKGROUND: The 2020 European Society of Cardiology atrial fibrillation guidelines recommend opportunistic screening for atrial fibrillation by pulse taking or ECG rhythm strip in those aged over 65 years. HYPOTHESIS: We aimed to compare the diagnostic accuracy of pulse palpation to ECG rhythm strip when screening for atrial fibrillation. A secondary aim was to investigate whether participants with palpitations were more likely to be diagnosed with new atrial fibrillation. METHODS: The study population were 75/76 year old individuals that participated in the STROKESTOP II study, a Swedish screening study for atrial fibrillation. Pulse palpation of the radial pulse for 30 sec was performed by healthcare professionals and recorded as regular or irregular. Thereafter a 30-sec single-lead ECG was registered. Patients were asked also if they had a history of palpitations. RESULTS: Of the 6159 participants included in the study, 461 (7.5%) had irregular pulse. Twenty-two (4.8%) of those with irregular pulse were diagnosed with atrial fibrillation on single-lead ECG rhythm strip. Among those with regular pulse, 6 (0.1%) cases of new atrial fibrillation were found. The sensitivity of the pulse palpation test was 78.6% and positive predictive value 4.8%. The proportion of newly diagnosed atrial fibrillation was not different between those with and without history of palpitations. CONCLUSION: Pulse palpation was inferior to single-lead ECG when screening for atrial fibrillation. We therefore advocate the use of single-lead ECG rather than pulse palpation when screening for atrial fibrillation. Palpitations did not predict atrial fibrillation.

Decentralising atrial fibrillation screening to overcome socio-demographic inequalities in uptake in STROKESTOP II.

OBJECTIVE: In the first STROKESTOP atrial fibrillation screening study, participation was influenced by socio-demographic and geographic factors. To improve uptake in the second study, two screening sites were added, closer to low-income neighbourhoods which had very low participation in the first study. This paper aims to analyse the geographic and socio-demographic disparities in uptake in the second trial and compare the results with the first trial. METHODS: Inhabitants of the Stockholm region born in 1940 and 1941 were randomised 1:1 to be invited to screening or serve as controls. Medical history, blood samples and single-lead-ECG were collected. Invitee's residential parish was used for geo-mapping analysis of the geographical disparities in participation, using hierarchical Bayes methods. Individual data for participants and non-participants were obtained for the socioeconomic variables: educational level, disposable income, immigrant and marital status. RESULTS: Higher participation was observed in those with higher education, high income, among non-immigrants and married individuals. Participation between the first and second studies improved significantly, where additional screening sites were introduced. These improvements were generally significant, in each population group according to socio-demographic characteristics. CONCLUSION: Decentralisation of screening sites in an atrial fibrillation screening program yielded a significantly positive impact on screening uptake. Adding local screening sites in areas with low uptake had beneficial impact on participation across a wide spectrum of socio-demographic groups. Decentralised screening substantially increased the screening uptake in deprived areas.

Brief episodes of rapid irregular atrial activity (micro-AF) are a risk marker for atrial fibrillation: a prospective cohort study.

BACKGROUND: Short supraventricular tachycardias with atrial fibrillation (AF) characteristics are associated with an increased risk of developing AF over time. The aim of this study is to determine if presence of very short-lasting episodes of AF-like activity (micro-AF) can also be used as a marker of undiagnosed silent atrial fibrillation. METHODS: In the STROKESTOP II study, a Swedish mass screening study for AF among 75- and 76-year-olds, participants with NT-proBNP ≥125 ng/L performed intermittent ECG recordings 30 s, four times daily for 2 weeks. Participants with micro-AF (sudden onset of irregular tachycardia with episodes of ≥5 consecutive supraventricular beats and total absence of p-waves, lasting less than 30 s) were invited to undergo extended AF screening using continuous event recording for 2 weeks. A control group of individuals without micro-AF was examined using the same ECG modalities. RESULTS: Out of 3763 participants in STROKESTOP II who had elevated NT-proBNP levels and were free of AF, n = 221 (6%) had micro-AF. The majority of participants with micro-AF (n = 196) accepted further investigation with continuous ECG monitoring which showed presence of AF in 26 of them. In the control group (n = 250), continuous monitoring detected 7 new AF cases. Thus, AF was significantly more common in the micro AF group (13%) compared to the control group (3%), p < 0.001. CONCLUSIONS: Presence of short-lasting episodes of AF-like activity (micro-AF) indicates increased likelihood for undetected AF. Continuous screening therefore seems recommendable if a finding of AF would change clinical management. TRAIL REGISTRATION: ClinicalTrials.gov, identifier: NCT02743416, registered April 19, 2016.