Temporal patterns of hospital admissions for transient ischemic attack: a retrospective population-based study in the Emilia-Romagna region of Italy.

Acute cerebrovascular events are not randomly distributed over time but show specific temporal patterns of occurrence. However, most studies focused stroke and little is known about transient ischemic attack. This study aimed to explore the existence of a temporal pattern of transient ischemic attack and the possible influence by the most common risk factors. The analysis included all hospital admissions with the ICD9-CM code for TIA, recorded in the database of the Emilia Romagna region of Italy (1998-2006; n = 43642, mean age 76.8 +/- 11.5 years, 45.5% males). Transient ischemic attack was most frequent in autumn and winter and less common in spring and summer (P < 0.0001), with the highest number of cases in October and the lowest in February, and also most frequent on Monday (P < 0.0001). This study shows a seasonal and weekly pattern in occurrence of transient ischemic attack, independent of sex and the presence of the most common risk factors.