Elsevier

Sleep Medicine

Volume 69, May 2020, Pages 155-158
Sleep Medicine

Original Article
Changes in atrial fibrillation admissions following daylight saving time transitions

https://doi.org/10.1016/j.sleep.2020.01.018Get rights and content

Highlights

  • Atrial fibrillation admission rates change following daylight-saving time transitions.

  • This trend was found following the Spring daylight-saving time transition.

  • It was not found following the Autumn daylight-saving time transition.

  • This trend persisted among women after separating by gender, but not men.

Abstract

Background

Daylight saving time (DST) imposes a twice-yearly hour shift. The transitions to and from DST are associated with decreases in sleep quality and environmental hazards. Detrimental health effects include increased incidence of acute myocardial infarction (MI) following the springtime transition and increased ischemic stroke following both DST transitions. Conditions effecting sleep are known to provoke atrial fibrillation (AF), however the effect of DST transitions on AF are unknown.

Methods

Admitted patients aged 18–100 with primary ICD9 code of AF between 2009 and 2016 were included. The number of admissions was compiled and means were compared for the Monday to Thursday period and the entire seven day interval following each DST transition and the entire year for the entire cohort and separated by gender. Significance was determined with Wilcoxon nonparametric tests.

Results

Admission data for 6089 patients were included, with mean age of 68 years and 53% female. A significant increase was found in mean AF admissions over the Monday to Thursday period (3.09 vs 2.47 admissions/day [adm/d], P = 0.017) and entire week (2.48 vs 2.09 adm/d, P = 0.025) following the DST spring transition compared to the yearly mean. When separated by gender, women exhibited an increase in AF admissions following the DST spring transition (1.78 vs 1.28 adm/d for Monday to Thursday period, P = 0.036 and 1.38 vs 1.11 adm/d for entire week, P = 0.050) while a non-significant increase was seen in men. No significant differences were found following the autumn transition for the entire cohort or when separated by gender.

Conclusion

An increase in AF hospital admissions was found following the DST springtime transition. When separated by gender, this finding persisted only among women. This finding adds to evidence of negative health effects associated with DST transitions and factors that contribute to AF episodes.

Introduction

Daylight saving time (DST) was first adopted in the early twentieth century to preserve resources in the spring and summer months. It is now implemented in over 70 countries and affects over 1.5 billion people around the globe [1]. Transitions to and from DST are characterized by moving the clock 1 h ahead in the spring and back in the autumn. These clock changes are associated with sleep cycle derangements, disruptions in circadian rhythm, increases in sleep fragmentation and latency leading to cumulative effects during the week following DST transitions [2], [3], [4], [5]. These same periods have been linked to environmental dangers including increased traffic accidents and workplace injuries [4], [6]. Health consequences associated with these transitions include increased incidence of ischemic stroke and acute myocardial infarction (MI) [7], [8], [9], [10], [11], [12]. Based on the adverse impact of DST transitions, the European Union convened an international group of specialists in August 2018 who recommended DST should be discontinued and the European Parliament voted in March 2019 to abolish the practice by 2021 [5], [13].

Sleep disordered breathing and sleep disruptions are known risks for atrial fibrillation (AF) [14], [15], [16]. Since DST transitions impact sleep and cardiovascular events, we sought to examine a link between DST transitions and AF. We are not aware of a prior study examining DST transitions and AF. We hypothesize that sleep cycle disturbances associated with DST transitions increase incidence of AF episodes. To examine this hypothesis, we performed a retrospective cohort study to examine the relationship between DST transitions and AF admissions at a large academic tertiary care medical center.

Section snippets

Methods

All hospitalizations with primary ICD9 diagnosis of AF for calendar years 2009–2016 for patients aged 18–100 at our single center were reviewed. We included International Classification of Diseases (Ninth Revision) 427.31 (atrial fibrillation), I48.0 (paroxysmal atrial fibrillation), and I48.91 (unspecified atrial fibrillation). We excluded I48.2 (chronic atrial fibrillation) and I48.1 (persistent atrial fibrillation). Demographic and patient characteristic information was obtained. Race and

Results

We included 6089 individuals admitted for AF to our center; 134 and 112 admissions occurred in the seven days following the DST spring transition and the DST autumn transition, respectively. The mean age was 68 ± 15 years with females composing 53% of subjects. There were no statistically significant differences between those admitted in the weeks following DST transitions compared to the rest of the year (Table 1).

Over the eight years analyzed, the mean daily admission rates for AF were

Discussion

Our data add to growing evidence suggesting transitions to and from DST, specifically the spring transition into DST, is associated with negative health outcomes and in particular cardiovascular disease. To the best of our knowledge, our study is the first to demonstrate a relationship between DST transitions and AF. Specifically, our data show an increase in AF hospitalization rates in the period following the spring transition to DST. When stratified by gender, this finding is driven by AF

Limitations

This study has several limitations. First, it is a retrospective analysis of data from a single center. Second, hospitalization ICD9 codes were used, not a review of patient records with electrocardiogram to confirm the diagnosis. Although ICD9 codes for chronic AF were excluded, some may have been miscategorized. Additionally, these codes would not account for planned admissions for procedures such as cardioversion or ablation. Third, we did not differentiate between new onset AF versus those

Conclusion

An increase in AF hospital admissions was seen following the spring DST transition, particularly among women. This finding adds to a growing body of evidence of health risks associated with DST transitions and extrinsic factors that contribute towards AF episodes. Further investigation is warranted on a larger scale to further explore the AF following DST transitions and gender differences. Consideration of continuing DST in light of potential negative health consequences is warranted.

CRediT authorship contribution statement

Jay J. Chudow: Conceptualization, Methodology, Investigation, Data curation, Formal analysis, Writing - original draft, Project administration. Isaac Dreyfus: Writing - original draft, Writing - review & editing. Lynn Zaremski: Conceptualization, Writing - review & editing. Alon Y. Mazori: Formal analysis, Investigation, Data curation. John D. Fisher: Conceptualization, Writing - review & editing. Luigi Di Biase: Conceptualization, Writing - review & editing. Jorge Romero: Conceptualization,

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