Case fatality of stroke and day of the week: is the weekend effect an artifact? Takashima stroke registry, Japan (1988-2003).

BACKGROUND AND PURPOSE: For stroke admissions, the 'weekend effect' has been associated with higher stroke fatality. However, it is unclear if stroke case fatality shows this pattern if the onset day is taken into account. Day of the week variation in stroke case fatality was examined using 16-year stroke registration data.

DESIGN AND METHODS: Data were obtained from Takashima Stroke Registry in central Japan. There were 1,578 registered first-ever cerebral infarction and cerebral hemorrhage stroke cases during 1988-2003. We divided the days into 2 groups: 'weekend' and 'weekdays'. The 7-day and 28-day case fatality rates and 95% confidence intervals (95% CI) were calculated by gender, age and stroke subtype.

RESULTS: For all strokes, the 7-day case fatality rate based on the hospital admission day was 9.5% (95% CI: 6.8-13.1) for weekend admissions and 7.3% (95% CI: 6.0-8.9) for weekday admissions. However, case fatality rates based on the onset day were 7.2% (95% CI: 5.1-10.0) for weekend onset and 8.0% (95% CI: 6.6-9.8) for weekday onset. The 28-day case fatality rate for the weekend admission group was 14.7% (95% CI: 11.3-18.8) and for the weekday admission group it was 10.1% (95% CI: 8.5-11.9). In contrast, the 28-day case fatality rate for the weekend onset group was 11.3% (95% CI: 8.6-14.7) and for the weekday onset group it was 11.0% (95% CI: 9.3-13.0). This phenomenon was observed mainly for cerebral infarction and to some extent for cerebral hemorrhage.

CONCLUSION: Stroke fatality rates based on the day of admission were higher during the weekend than weekdays, although the difference did not reach statistical significance. However, this trend disappeared when the fatality rate was based on the day of onset.