(Stroke. 1999;30:709-714.)
© 1999 American Heart Association, Inc.
Original Contributions |
From the Department of Medicine, University Hospital, Umeå (B.S., K.A., M.P.); Department of Medicine, Enköping Hospital (K.H.-Å.); Department of Medicine, University Hospital, Uppsala (A.T.); Department of Neurology, University Hospital, Lund (B.N.); and Swedish National Board of Health and Welfare, Stockholm, Sweden (P.O.W.).
Correspondence to Dr Birgitta Stegmayr, Department of Medicine, University Hospital, S-901 85 UMEÅ, Sweden. E-mail birgitta.stegmayr{at}medicin.umu.se
| Abstract |
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MethodsA multicenter observational study of procedures and outcomes in acute stroke patients admitted to designated SUs or general medical or neurological wards (GWs), the study included patients of all ages with acute stroke excluding those with subarachnoid hemorrhage, who were entered into the Riks-Stroke (Swedish national quality assessment) database during 1996 (14 308 patients in 80 hospitals).
ResultsPatients admitted to SUs who had lived independently and who were fully conscious on admission to the hospital had a lower case fatality than those cared for in GWs (relative risk [RR] for death, 0.87; 95% confidence interval [CI], 0.79 to 0.96) and at 3 months (RR, 0.91; 95% CI, 0.85 to 0.98). A greater proportion of patients cared for in an SU could be discharged home (RR, 1.06; 95% CI, 1.03 to 1.10), and fewer were in long-term institutional care 3 months after the stroke (RR, 0.94; 95% CI, 0.89 to 0.99). No difference was seen in outcome in patients cared for in SUs or GWs if they had impaired consciousness on admission.
ConclusionsThe improvement in outcomes after stroke care in SUs compared with care in GWs can be reproduced in the routine clinical setting, but the magnitude of the benefit appears smaller than that reported from meta-analyses.
Key Words: randomized controlled trials stroke outcome stroke units stroke, acute
| Introduction |
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In this study the impact of routine care of stroke patients in SUs has been examined. The study was made possible by the implementation of Riks-Stroke, a nation-wide quality assessment register for patients with acute stroke.
| Subjects and Methods |
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Data collection in Riks-Stroke is kept simple to ensure maximum coverage; it includes information on the patient's sex, age, history of previous stroke, life situation before the current stroke, and need of assistance in 3 primary ADL functions (namely, mobility, personal hygiene, and dressing/undressing). Items related to acute care include the time from the onset of symptoms to admission to hospital, type of department to which the patient is admitted (eg, medical, neurological, or geriatric), whether or not the unit has organized stroke care (stroke unit), the patient's level of consciousness on admission, whether or not a CT scan was performed, and, in patients who died, whether or not a postmortem was performed. In addition, drug treatment during the acute phase was added from 1998. Details registered at discharge included the duration of the acute admission to hospital, diagnosis of the stroke type according to the Riks-Stroke criteria (included in the computer program available at each participating unit), the patient's status at discharge (alive or dead), and details of further management (at home or in an institution), and whether or not they required further care in an institution. Each patient registered in Riks-Stroke was followed up 3 months after the stroke, and a 9-item form was filled in by the patient, a family member, or, in the case of institutionalized patients, who were unable to respond themselves, by a staff member. In many hospitals these data were obtained by telephone interviews by the staff of the acute unit. In this study 30.5% of the follow-up forms were completed by the patient, 12.5% by a family member, 52.6% by staff at a hospital or other institution, and 4.3% by someone else. Data on living (whether alone, with relatives, or in an institution) and degree of function (as recorded before the stroke) and, from 1998, patient satisfaction with the in- and outpatient care received at the hospital were also recorded.
In the Riks-Stroke collaboration, an acute stroke is defined by the WHO criteria,6 and a stroke unit as a service provided by a designated stroke ward or stroke team working exclusively in the care of stroke patients.3 This report presents data collected during 1996 during which 14 300 patients were admitted to 87 units in 80 hospitals (in some hospitals, patients with acute stroke were admitted to different departments; medical, geriatric, or neurological) and registered in the Riks-Stroke database. Patients with subarachnoid hemorrhage were excluded from the study because the majority of them were managed in neurosurgical units, not included in Riks-Stroke.
Descriptive data are shown as means, medians, and proportions with their 95% confidence intervals (95% CI). Comparisons of outcome between patients cared for in SUs and GWs are presented as relative risks with 95% CI. Continuous variables were compared using a 1-way ANOVA by ranks (the Kruskal-Wallis test). Logistic regression was used for adjustments for covariates. All calculations were made using the SPSS statistical package.7
| Results |
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The majority of patients (8642; 60.4%) were treated in a SU in the acute phase, and 4752 (33,2%) were treated in a l medical or neurological ward (GW). A total of 913 patients (6.4%) were treated in settings that did not fulfill the criteria for SUs or GWs (eg, admitted for observation and treatment in emergency departments or directly to rehabilitation units). They were excluded from further comparisons between SU and GW patients (information on type of acute stroke service was missing in 1 patient).
Initial analyses showed an imbalance in functional dependency
before the stroke event between patients admitted to SUs and GWs. To
make direct comparisons of outcome between the 2 settings possible, the
ensuing analyses were restricted to patients who were living at
home without community support. Among these patients, those who had
been treated in SUs and GWs did not differ in marital status or ADL
functions before the stroke, or in the prevalence of previous stroke
(Table 1
). GW patients were, on
average, 1.2 years older than SU patients. The major difference in
prognostic variables was a significantly higher proportion of GW
patients presenting with impaired consciousness on admission to
hospital. In the SUs, a significantly larger proportion of patients
underwent CT scanning (93.8% versus 87.4% in the GWs;
P<0.0001 by
2 test). This resulted
in a lower proportion of patients left with an unspecified stroke
subtype at discharge from the SUs compared with the GWs (Table 1
).
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Because of the uneven distribution of patients with lowered
consciousness between the 2 clinical settings, the following
analyses of outcome, presented in Table 2
, were stratified by level of
consciousness.
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Early Outcome in Patients With Unimpaired Consciousness
Among patients who were living at home without community
support before the stroke event and those who did not have lowered
consciousness on admission to the hospital, the mean length of hospital
stay was 0.8 days longer in the SUs than in the GWs (Table 2
), a
difference that was statistically significant (P=0.0002 by
the Kruskal-Wallis test). A significantly higher proportion of those
treated in SUs was discharged to home and a significantly lower
proportion to nursing homes. Furthermore, when patients discharged to
any type of institutional care were considered as a single group, there
was a significant reduction in SU patients. The absolute risk
reductions in favor of the SUs were all modest. In comparison with GW
care, for 1000 patients admitted to SUs, 35 more were able to return to
home, 16 fewer were transferred to nursing homes, and 23 fewer to
institutional care of any type.
Case fatality during the stay in the acute ward was low in SU and GW
patients, but it was significantly lower in those treated in SUs (Table 2
), with 13 fewer deaths per 1000 patients admitted. The
differences in proportion discharged to further institutional care and
in case fatality remained statistically significant after adjustment
for the small difference in age between SU and GW patients in a
logistic regression model (P<0.0001 for both outcomes).
Early Outcome in Patients With Impaired Consciousness on
Admission
In patients with independent living before the stoke event but
arriving at the hospital with impaired consciousness, the length of
hospital stay was, on average, 2.1 days longer in the SUs (Table 2
). Case fatality during the hospital stay was about 6 times
higher than in patients presenting with an unaffected level of
consciousness. There was no significant difference in case fatality
between the SU and GW patients. In fact, in patients with impaired
consciousness, the only significant difference at discharge from the SU
was that a larger proportion was transferred to geriatric or other
rehabilitation units.
3-Month Follow-up
At 3 months' follow-up, the only difference between SU and GW
patients that persisted as statistically significant was a lower
proportion in long-term institutions if the patients had been treated
in an SU in the acute phase (Table 2
). This difference was only
observed in patients who arrived at the hospital without impaired
consciousness. For 1000 patients admitted, there were 20 fewer in a
long-term institution at 3 months after the stroke. This difference
remained statistically significant (P<0.0001) after
adjustment for age in a logistic regression model. There were only weak
tendencies toward better outcome in primary ADL proficiency at 3
months' follow-up in SU patients (Table 2
).
Outcome in Hospitals With and Without Good Access to SU
Services
In the majority of hospitals covered by the Riks-Stroke register,
the number of beds in SUs was not sufficient to accommodate all
patients with acute stroke. As presented above, imbalance in
prognostic factors between patients selected to SUs and GWs,
respectively, was corrected by restricting the analyses to
patients who were living independently before the stroke and by
stratification for level of consciousness on admission. To further
reduce the influence of any possible imbalance between patients
admitted to SUs and GWs, the clinical outcome in patients treated in
hospitals in which the great majority of patients (85% or more) were
treated in an SU was compared with that in hospitals in which the great
majority (
85%) of stroke patients were admitted to a GW. The
denominator being all stroke events reported to Riks-Stroke from the
individual hospitals. This comparison was possible because all Swedish
hospitals admitting acute stroke patients are part of the national
health system, and each has a defined local catchment area. Thirteen
hospitals were in the group with
85% of patients in SUs and 11
hospitals in the group with
85% in GWs.
Prognostic variables did not differ significantly between patients
treated in hospitals with and without good access to SU care (data not
shown), except that a significantly higher proportion in hospitals with
low access to SU care was recorded as having impaired consciousness
on admission. Therefore, stratification by level of consciousness was
done in the comparisons of outcome. The proportion of patients with
unspecified stroke subtype was 3 times higher in hospitals with
85%
of patients in GWs as compared with hospitals with
85% in SUs
(14.9% versus 4.4%; P<0.0001 by
2 test).
The clinical outcome in the 2 types of hospitals, stratified by level
of consciousness on admission, is compared in Table 3
. A picture emerges similar to the one
in comparisons between patients in SUs and GWs (Table 2
). The
length of hospital stay in patients without impaired consciousness was
significantly shorter in patients with
85% of stroke patients in
SUs. The other major difference was found in case fatality. In
hospitals with a high proportion of patients in SUs, the case fatality
was lower, not only in subjects without but even in subjects with
impaired consciousness on admission. This difference in case fatality
between hospitals persisted in both groups at 3 months' follow-up
(Table 3
). Adjustments for the small differences in patient age
between the 2 types of hospitals in a logistic regression model
produced identical results (data not shown).
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| Discussion |
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Membership in the Riks-Stroke collaboration is voluntary, but by 1998 all hospitals in Sweden admitting patients with acute stroke had joined. The registry is still being built up because a number of hospitals do not as of yet have full coverage of all stroke patients. In 1996, the year for which data are reported in this study, the database included 14 308 cases (excluding those with subarachnoid hemorrhage). Routine hospital statistics for 1996 showed that a total of 25 222 patients had been admitted to the hospital with a diagnosis at discharge of acute stroke.8 Previous validations have shown a considerable overdiagnosis of acute stroke in routine practice.9 Thus, as a crude estimate, approximately 70% to 75% of all patients suffering an acute stroke in Sweden in 1996 were included in the present study.
Patients admitted to SUs and GWs were initially found to differ in key prognostic factors. Although a history of previous stroke was equally common in the 2 patient groups, a somewhat higher proportion of patients admitted to GWs had already been dependent on others for care before the current stroke, and more patients admitted to GWs also had impairment of consciousness on admission to hospital. To minimize the effects of a selection bias, only patients who had been living at home without support from the community were included, and they were stratified by level of consciousness on admission. This selection produced groups of patients admitted to SUs and GWs that were closely similar in prognostic factors. However, because this is an observational study, there still may be an imbalance in prognostic factors not recorded in the Riks-Stroke registry. The great advantage of the present study is that it measures outcome in routine clinical practice and that the patient groups are large enough to allow subgroup analyses with adequate statistical power.
To further reduce any possible bias in the selection of patients admitted to SUs and GWs, the clinical outcome in hospitals in which the great majority of patients were treated in SUs was compared with that in hospitals in which few or no stroke patients had access to SU care. Several population-based epidemiological studies have shown that 95% or more of all patients suffering an acute stroke in Sweden are admitted to hospital.9 10 11 12 Because all hospitals in Sweden that admit patients with acute stroke serve a defined geographical area, it seems probable that group comparisons between hospitals with different types of stroke services will be based on similar case mixes. Nevertheless, hospitals in which few or no patients were admitted to an SU reported a greater proportion of patients with impaired consciousness on admission. Whether this reflects differences in examination practices and skills or is due to a true difference in case mix has yet to be ascertained. We have therefore also stratified patients by level of consciousness in our comparisons between hospitals with different stroke services.
Computerized tomography is available in all Swedish hospitals that admitted patients with stroke. Nevertheless, brain CT scanning was performed more often in patients admitted to SUs than in those admitted to GWs, and this resulted in a smaller proportion of patients who had an unspecified stroke diagnosis at discharge in the SU group. This item has been selected as one of the quality indicators of acute stroke management in Riks-Stroke.
There were several differences in outcome between patients admitted to SUs and GWs supporting the findings of the randomized trials of SU care with effects on survival and on the need for institutional care after the acute phase.2 3 4 Although the results of the present study were qualitatively similar to those of the randomized trials, the effects of SU care were quantitatively smaller. On the other hand, the results in the randomized trials are presented as an odds reduction, which is not the same as relative reduction. In an article from the Stroke Unit Trialists' Collaboration, they reported that SU care was associated with 50 of 1000 patients returning home independently, and 10 of 1000 fewer patients going to institutional care.13 Our results are rather comparable, with 35 of 1000 extra returning home, and 16 fewer were transferred to nursing homes. Although, there are also several possible explanations for the relatively smaller effect in the present study compared with that found in the randomized trials.
First, there may have been a selection bias in hospitals in which patients with stroke were managed in GWs. Hospitals that entered the Riks-Stroke collaboration early on probably had a particular interest in stroke care, even if a formal SU had not been established. This possible selection bias may have reduced the differences in outcome between patients admitted to SUs and those admitted to GWs. Second, the majority of the trials included in the meta-analyses were performed during the 1970s and 1980s, before improvement in general knowledge and interest in stroke care occurred in doctors, nurses, and rehabilitation staff.1 2 3 4 The concept of the SU has probably provided a general stimulus for stroke management and has perhaps also influenced the quality of stroke care in hospitals with no formal SU. This would tend to reduce differences in care in patients admitted to SUs and GWs today compared with when SUs were first introduced. Third, there may be a dilution effect of any intervention when it is transferred from randomized trials to routine clinical practice. The organization and staffing of an SU (or a stroke team) may vary considerably between units. Features common to all SUs are that they are hospital-based, have a systematic organization of stroke services, and use an interdisciplinary approach to stroke management.3 4 However, these basic features allow for a considerable variation in practice. Thus, it may be assumed that adherence to the basic principles of SU organization and the quality of stroke management vary between the SUs taking part in the present study. This would also dilute the overall effects of SU care on the national level and also provide an impetus for improvement in stroke management in many hospitals that have SUs. The Riks-Stroke registry, by providing feedback information on the quality of care and the outcomes of stroke, serves to stimulate this development.
| Acknowledgments |
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| Footnotes |
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| Appendix 1 |
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Steering Committee
P.O. Wester (chair), Kjell Asplund, Back Per Danielsson, Kerstin
Hulter-Åsberg, Bo Norrving, Birgitta Stegmayr, Andreas Terént,
and Margareta Thorngren.
Monitor
Ann Staaf
Computer Records and Data Analyses
Birgitta Stegmayr (coordinator), Eva-Lotta Glader, Roger
Jacobsson, and Markku Peltonen
Received November 26, 1998; revision received January 11, 1999; accepted January 12, 1999.
| References |
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