(CCSP010) ASSOCIATION BETWEEN DAYLIGHT SAVING TIME AND ACUTE MYOCARDIAL INFARCTION IN CANADA: THE DST-AMI STUDY

Background: Recent studies have suggested an increased risk of acute myocardial infarctions (AMI) following daylight saving time (DST) transitions in cohorts of American and European patients. We aim to validate this finding in a Canadian population.

METHODS AND RESULTS: We performed a retrospective cohort study of patients admitted to the Hôpital du Sacré-Coeur de Montréal with a diagnosis of AMI requiring a percutaneous coronary intervention (PCI). Patients aged ≥18 years hospitalized between 2018 and 2022 were included. The primary endpoint was the incidence of AMI two weeks following DST transitions in spring and autumn. This period was considered the hazard period while control periods included two weeks before and two weeks following the hazard period. The secondary endpoint was infarct size by biomarker assessment and left ventricular ejection fraction (LVEF). 1020 charts were reviewed with 661 patients meeting the inclusion criteria. 208 patients were included in the study group and 453 in the control group. The mean age was 65 ± 12 years and 29% were women. Baseline clinical characteristics were comparable between the two groups. (Table 1) The rate of AMI per day following DST transitions was 1.49 compared to 1.62 during control periods. DST was not associated with an increase in AMI (incidence rate ratio (IRR) = 0.92, p = 0.164). (Table 2) During the spring shift, the IRR was 0.82, p = 0.244 and during the autumn shift the IRR was 1.02, p = 0.233. The rate of AMI was slightly higher on the first day following DST, but it did not reach statistical significance (rate of AMI per day = 1.90; IRR = 1.17; p = 0.419). The transition to DST was not associated with a larger infarct size (maximal CK-MB level 139 ± 201 µg/L for the study group vs 146 ± 294 µg/L for the control group, p = 0.770 and LVEF 50 ± 11 % vs 48 ± 10 %, p = 0.057).

Conclusion: In this cohort of Canadian patients, there was no significant association between DST transitions and the incidence of AMI. Infarct size was similar between study and control groups.