Intracranial Hemorrhage After Ischemic Stroke: Incidence, Time Trends, and Predictors in a Swedish Nationwide Cohort of 196 765 Patients

Background: Epidemiological data on the risk of intracranial hemorrhage (ICrH) after ischemic stroke are sparse. The aims of this study were to describe incidence, trends over time, and predictors of ICrH within 1 year after ischemic stroke.

Methods And Results: All patients registered in the Swedish stroke register Riksstroke for 1998 to 2009 were included (n=196 765), and data were combined with the National Patient Register to identify ICrH occurrence. A matched reference population was obtained. Incidence rates and cumulative incidences were calculated. Multivariable regression analyses were used to identify predictors. Analyses were performed separately for the first 30 days and days 31 to 365 after ischemic stroke. The incidence rate was 1.97% per year at risk for the first year (0.13% in the reference population) and 0.85% excluding the first 30 days. Over time, the cumulative incidence increased the first 30 days but decreased over days 31 to 365. Thrombolysis, previous ICrH, atrial fibrillation, and male sex were associated with increased risk of ICrH during the first 30 days. Previous ICrH, increasing age, and male sex were associated with increased risk during days 31 to 365. Statins and antithrombotic treatment did not independently predict ICrH occurrence.

Conclusions: The incidence of ICrH within 1 year after ischemic stroke was ≈2% per year at risk, about 15 times higher compared with the reference population. Over the study period, ICrH risk increased within the first 30 days but decreased thereafter. Previous ICrH, thrombolysis, and male sex affected the risk, whereas an increased use of antithrombotic treatments and statins did not.