Abstract P215: Trends in Hemorrhagic Stroke in Japan, from 1986 to 2010: Circulatory Risk in Communities Study (CIRCS).
Background: The incidence of hemorrhagic stroke has substantially decreased nearly to a quarter over years from 1960s to 1980s in Japan. However, there is little evidence on the trends after 1980, or whether subtypes of hemorrhagic stroke have decreased. We examined trends in the incidence of hemorrhagic stroke and its subtypes.
Hypothesis: Hemorrhagic stroke have decreased after 1980s. For intraparenchymal hemorrhage (IPH), lobar and cerebellar intraparenchymal hemorrhage has not decreased.
Methods: All residents aged 30 to 84 years in two communities (Akita and Osaka, census population: 18,998 in 2000) in Japan was surveyed. The incidence of IPH and subarachnoid hemorrhage (SAH) from 1986 to 2010 was ascertained by systematic surveillance of hospital records and confirmed by physicians with CT or MRI images. The implementation rate of CT or MRI has not changed materially over years (78.9~97.4%). IPH was further categorized to lobar and cerebellar IPH, and deep IPH (thalamus, basal ganglia or brainstem). The respective age-adjusted incidence rates per 100,000 person-years were calculated by each 5 years of time periods: 1986-1990, 1991-1995, 1996-2000, 2001-2005, and 2006-2010.
Results: Age-adjusted incidence of SAH has decreased in 1996-2000 but increased after 2000. Respective age-adjusted incidence rates (per 100,000 person-years) of SAH for 5 time periods were 46.2, 46.5, 14.5, 23.0, and 23.7 (p for trend=0.23). Age-adjusted incidence of all IPH has decreased from 1986-1990 to 2006-2010. Respective incidence rates of IPH were 56.8, 53.7, 48.7, 29.0, and 26.5 (p for trend=0.01). For the subtypes of IPH, incidence of lobar and cerebellar IPH has not decreased from 1986-1990 to 2006-2010, while it have decreased for deep IPH. Respective incidence rates for lobar and cerebellar IPH were 13.1, 7.6, 16.6, 10.9, and 10.3 (p for trend=0.85) and those of deep IPH were 52.0, 53.1, 49.8, 40.8, and 29.5 (p for trend=0.03).
Conclusion: The age-adjusted incidence of IPH after 1980s has decreased over years, although such trend was not clear for SAH. Among IPH, the incidence of lobar and cerebellar IPH has not decreased, while the incidence of deep IPH has decreased.
- © 2013 by American Heart Association, Inc.