Daylight saving time and the incidence of thrombolysis to treat acute ischemic stroke.

BACKGROUND

Twenty-five percent of the global population lives in one of the more than 70 countries that observe daylight saving time (DST). These people are exposed to 1hour of time transition twice a year, influencing the circulatory system. We aimed to analyze the incidence of thrombolysis to treat acute ischemic stroke in relation to clock changes in Hungary over a 10-year period.

METHODS

The number of thrombolytic treatments performed within the period between 2006 and 2015 was analyzed. Anonymized nationwide data on the dates and exact daily numbers of thrombolysis interventions were provided by the National Health Insurance Fund. We compared the mean number of thrombolytic treatments on the day before with that on the day after each transition, and also between the preceding and following one week and month.

RESULTS

Our data including the last days of each month suggested a significant increase in thrombolysis numbers both in spring and in autumn on the day and the week after the clock change. However, when the last days of each month were excluded from analysis (as this in itself was associated with a 7-fold increase in stroke incidence in our earlier study), no significant difference in the number of thrombolysis treatments between the days and weeks before and after the clock change was detectable. The long-term, monthly analysis also did not reveal a significant difference.

CONCLUSIONS

Our findings reflect that psychosocial factors, such as the approach of the last day of the month override the intrinsic effect of disturbances of the circadian rhythm on stroke incidence.