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Improvement in Stroke Survival by Subtype
II During the 1980s:
Minnesota Stroke Survey
The Minnesota Stroke Survey (MSS)
was undertaken to determine whether survival of hospitalized
stroke patients had changed during the 1980s. Each of
three period cohorts (1980, 1985, 1990), totaling 1853 patients,
was followed for at least 2 years for a primary end point
of all-cause mortality.
An improved survival rate over the 10-year span
was evident in the short term (28 days) as well as for patients
who survived longer. Based on either MSS or World Health
Organization (WHO) criteria for stroke, the age-adjusted odds
of death within 2 years after the even were approximately
40% lower in 1990 than in 1980.
Trend analysis by stroke subtype indicated that
most of the improved survival was attributable to improved
odds of surviving an ischemic stroke, primarily among patients
with no apparent cardioembolic source. Based on MSS
stroke criteria, the relative odds of 2-year death in 1990
(versus 1980) were 0.42 for thrombotic stroke, 0.78 for possibly
embolic stroke, and 0.42 for stroke of underdetermined type.
There was no evidence of improved survival over time for patients
with hemorrhagic stroke.
The investigators suggested two possible explanations
for the observed improvements. One was better supportive
and rehabilitative care (eg, improved management and/or prevention
of sequelae such as pulmonary embolism or bronchopneumonia
or of coexisting cardiac disease). A second potential
explanation was a change in the natural history of stroke,
with stroke becoming a less severe disease; the investigators
suggested, for example, that improved levels of cardiovascular
disease risk factors, although primarily thought to decrease
stroke incidence, may have resulted in better prognosis for
those suffering a stroke.
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Stroke Education
