Volume 164, November 2022, 107284AbstractBackground

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.

Introduction

Participation is key in the success of any screening program. The characteristics of participants vs. non-participants have previously been studied and those that do not participate appear often to be the ones that have higher risk of disease (Poiseuil et al., 2019). Cardiovascular mortality has been reported to be higher among persons of lower socioeconomic status (Mackenbach et al., 2000). Low socioeconomic status has also been associated with increased morbidity and mortality in AF patients (Lunde et al., 2018).

Various methods to increase participation, as well as strategies to try to decrease the socioeconomic gradient noted in screening uptake, have been investigated (Cheong et al., 2017; Wardle et al., 2016). A review from 2020 failed to verify that interventions aimed at improving screening participation in low socioeconomic areas resulted in more even cancer-related outcomes between areas (Bygrave et al., 2020). In contrast, decentralization of screening sites increased screening uptake in deprived areas in a sub-study to the STROKESTOP II study (Gudmundsdottir et al., 2020). Detailed understanding of the characteristics of non-participants could possibly help design more targeted screening programs. The potential yield of screening-detected disease in non-participants could be of interest to various screening programs. The STROKESTOP II study is an atrial fibrillation (AF) screening study with the aim to reduce the burden of AF related stroke (Kemp Gudmundsdottir et al., 2020). This sub-study to STROKESTOP II aim is to compare characteristics of non-participants and participants predicting participation, as well as to estimate the potential yield of screening-detected disease in non-participants.

Section snippetsParticipants

The study design and baseline results of the STROKESTOP II study have previously been published (Kemp Gudmundsdottir et al., 2020; Engdahl et al., 2016). Briefly, all inhabitants in the Stockholm region born 1940 and 1941 were identified using their personal identification number by Statistics Sweden and after gender-and age-based 1:1 randomization half of the inhabitants were invited to participate in an AF screening study. There were no other inclusion criteria and no exclusion criteria. The

Non-participants and participants' characteristics

The final sample consisted of 6868 participants and 7086 non-participants. We excluded individuals who died (n = 340) or emigrated from Sweden (n = 10) prior to having received their last invitation.

Non-participants were more likely to have been hospitalized in the 5 years preceding the index date, spent more days hospitalized in the last year prior to index date and were discharged to a retirement home more frequently when compared to participants. They had a higher CHA2DS2-VASc score, a

Discussion

We found that individuals who did not participate in the STROKESTOP II study could generally be considered poorer in health and of lower socioeconomic status than the participants.

The estimated detection of actionable AF by screening in the non-participants yielded similar proportion as in the participants. However, the non-participants had higher CHA2DS2-VASc scores on average, highlighting their increased risk of stroke and possible benefit from detection of AF through screening.

Systematic

Conclusion

In a Swedish atrial fibrillation screening study (STROKESTOP II study), we found that non-participants were of poorer health and had lower socioeconomic status than participants. Estimated new AF was not significantly higher in non-participants compared to participants but non-participants had higher CHA2DS2-VASc scores, highlighting their high stroke-risk and probable benefit of attending screening.

In planning future screening scenarios focus should be put on how to reach those less likely to

Funding credits and disclosure of potential and real conflicts of interest

Katrin Kemp Gudmundsdottir has received speaker/lecture fees from Pfizer, Boehringer Ingelheim, Roche Diagnostics. Research grants from Roche Diagnostics, The Stockholm Region, Carl Bennet AB, The Swedish Heart & Lung Foundation.

Carl Bonander reports Research grants from the Swedish Research Council for Health, Working Life and Welfare (grant number: 2020–00962), the Kamprad Family Foundation, the Swedish Cancer Society, and Handelsbanken.

Tove Hygrell reports financial support provided by

CRediT authorship contribution statement

Katrin Kemp Gudmundsdottir: Conceptualization, Methodology, Formal analysis, Investigation, Writing – original draft, Writing – review & editing, Visualization. Carl Bonander: Conceptualization, Methodology, Formal analysis, Data curation, Writing – review & editing, Visualization. Tove Hygrell: Investigation, Writing – review & editing. Emma Svennberg: Conceptualization, Investigation, Writing – review & editing, Project administration, Funding acquisition. Viveka Frykman: Conceptualization,

Declaration of Competing Interest

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:

Katrin Kemp Gudmundsdottir has received speaker/lecture fees from Pfizer, Boehringer Ingelheim, Roche Diagnostics. Research grants from Roche Diagnostics, The Stockholm Region, Carl Bennet AB, The Swedish Heart & Lung Foundation.

Carl Bonander reports Research grants from the Swedish Research Council for Health, Working Life and Welfare (grant number: 2020–00962),

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