Daylight savings time and myocardial infarction
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  • Published on:
    The Impact of Daylight Savings Time Change on the Incidence of Percutaneous Coronary Intervention for Acute Myocardial Infarction
    • Milan Seth, Statistician University of Michigan
    • Other Contributors:
      • Amneet Sandhu, Cardiologist
      • Hitinder Gurm, Cardiologist

    Five years ago, our group at the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2) published an analysis exploring the impact of day light saving time (DST) changes on the state -wide volume of percutaneous coronary intervention in patients presenting with acute myocardial infarction (AMI-PCI) in the weekdays following the time change.1 Using data from our clinical registry reflecting all PCIs performed at non-Federal hospitals throughout Michigan between 1/1/2010 and 9/15/2013, we identified a significant increase in AMI-PCI on Mondays following the Spring DST change (RR = 1.24, p = 0.011), and a significant reduction in cases on Tuesdays following fall DST changes (RR = 0.79, p = 0.044), adjusting for seasonal and weekday effects, and for an overall time trend. We have now repeated the analysis using registry data for the subsequent 5 ½ years, from 9/16/2013 – 3/31/2019 using the same methodology and obtained results inconsistent with our prior publication. In our analysis of more recent data, both of the previously reported effects were substantially attenuated and are no longer statistically significant (Spring Monday after change: RR = 1.095, p = 0.207; Fall Tuesday after change: RR = 0.96, p = 0.553). Our prior publication garnered a great deal of attention in the popular media2,3, often with alarming, sensational headlines. It has also been included in meta-analysis along with other publications identifying a similar Spring time change effect4...

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    Conflict of Interest:
    This work was supported by the Blue Cross Blue Shield of Michigan and Blue Care Network as part of the Blue Cross Blue Shield of Michigan Value Partnerships program. The funding source supported data collection at each site and funded the data-coordinating center but had no role in study concept, interpretation of findings, or in the preparation, final approval or decision to submit the manuscript.
    Although Blue Cross Blue Shield of Michigan (BCBSM) and BMC2 work collaboratively, the opinions, beliefs and viewpoints expressed by the author do not necessarily reflect the opinions, beliefs and viewpoints of BCBSM or any of its employees.
    Hitinder S. Gurm receives research support from Blue Cross Blue Shield of Michigan, NIH Center for Accelerated Innovations (NCAI), and Michigan Translational Research and Commercialization for Life Sciences (MTRAC) Innovation Hub. Consultant; Osprey Medical. All other authors have nothing to disclose.