A 10-year registry analysis of 168,870 patients with acute myocardial infarction found no difference in incidence or in-hospital outcomes during daylight saving time weeks compared with the weeks immediately before or after.
In the Chest Pain–MI Registry analysis (American College of Cardiology National Cardiovascular Data Registry), researchers led by Dr. Jennifer A. Rymer of Duke University Medical Center evaluated patients treated at 1,124 hospitals between 2013 and 2022 (median age, 65 years; about one-third women). In spring, cases totaled 28,596 in the week before daylight saving time (DST), 28,678 during the transition week, and 28,169 the following week; in fall, cases were 27,365 before the shift, 27,942 during, and 28,120 following. Patient characteristics were similar across weeks.
The primary outcome was in-hospital mortality. Secondary outcomes were in-hospital stroke, revascularization for non–ST-segment elevation myocardial infarction (NSTEMI), and reperfusion for ST-segment elevation myocardial infarction (STEMI)—as defined in the registry.
Results showed no statistically significant differences in acute myocardial infarction (AMI) incidence when comparing each DST week with the adjacent weeks in spring or fall, and no differences in adjusted in-hospital outcomes across the transitions. Adjusted analyses accounted for demographics, comorbidities, cardiac function, renal function, biomarkers, and arrival era.
Sensitivity analyses supported the main results. In states that do not observe DST (Arizona and Hawaii), incidence ratios remained stable across indexed weeks; extending comparisons to 3 weeks before and after produced similar findings. Excluding 2020–2021 did not change results.
One exception occurred in 2020: patterns during the early COVID-19 period differed from other years, which the researchers note could reflect pandemic-related factors and seasonal respiratory virus surges that affect AMI incidence.
Funding and Disclosures: The study reports National Heart, Lung, and Blood Institute support (grants 5K23-HL166691-02, UG3HL171357, U24HL171356) and backing from the American College of Cardiology National Cardiovascular Data Registry. Reported conflicts included support to one coauthor from the Department of Veterans Affairs and grants/consulting to another; other authors reported no disclosures. Funders had no role in the study conduct, analysis, or publication decision.
Source: JAMA Network Open