Tom Skyhøj Olsen

Body temperature in acute stroke: relation to stroke severity, infarct size, mortality, and outcome

BACKGROUND In laboratory animals, cerebral ischaemia is worsened by hyperthermia and improved by hypothermia. Whether these observations apply to human beings with stroke is unknown. We therefore examined the relation between body temperature on admission with acute stroke and various indices of stroke severity and outcome. METHODS In a prospective and consecutive study 390 stroke patients were admitted to hospital within 6 h after stroke (median 2.4 h). We determined body temperature on admission, initial stroke severity, infarct size, mortality, and outcome in survivors. Stroke severity was measured on admission, weekly, and at discharge on the Scandinavian Stroke Scale (SSS). Infarct size was determined by computed tomography. Multiple logistic and linear regression outcome analyses included relevant confounders and potential predictors such as age, gender, stroke severity on admission, body temperature, infections, leucocytosis, diabetes, hypertension, atrial fibrillation, ischaemic heart disease, smoking previous stroke, and comorbidity. FINDINGS Mortality was lower and outcome better in patients with mild hypothermia on admission; both were worse in patients with hyperthermia. Body temperature was independently related to initial stroke severity (p < 0.009), infarct size (p < 0.0001), mortality (p < 0.02), and outcome in survivors (SSS at discharge) (p < 0.003). For each 1 degrees C increase in body temperature the relative risk of poor outcome (death or SSS score on discharge < 30 points) rose by 2.2 (95% CI 1.4-3.5) (p < 0.002). INTERPRETATION We have shown that, in acute human stroke, an association exists between body temperature and initial stroke severity, infarct size, mortality, and outcome. Only intervention trials of hypothermic treatment can prove whether this relation is causal.

Outcome and time course of recovery in stroke. Part II: Time course of recovery. The copenhagen stroke study

OBJECTIVE To determine the time course of both neurological and functional recovery from stroke. DESIGN Prospective, consecutive, and community based. SETTING The stroke unit of a hospital in Copenhagen, Denmark. This setting receives all acute stroke patients admitted from a well-defined catchment area of 239,886 inhabitants within the city of Copenhagen. Acute treatment as well as all stages of rehabilitation are cared for within the stroke unit regardless of age, stroke severity, and premorbid condition. PATIENTS 1,197 patients with acute stroke. MAIN OUTCOME MEASURES Weekly examinations of neurological deficits (using the Scandinavian Neurological Stroke Scale) and functional disabilities (Activity of Daily Living (ADL) measured by the Barthel Index) were performed from the time of acute admission to the end of rehabilitation. These evaluations were repeated 6 months poststroke. Time course of recovery was stratified according to initial stroke severity and disability. RESULTS Functional recovery was completed within 12.5 weeks (95% confidence interval (CI) 11.6 to 13.4) from stroke onset in 95% of the patients. However, 80% of the patients had reached their best ADL function within 6 weeks (CI 5.3 to 6.7) from onset. The time course of functional recovery was strongly related to initial stroke severity. Best ADL function was reached within 8.5 weeks (CI 8 to 9) in patients with initially mild strokes, within 13 weeks (CI 12 to 14) in patients with moderate strokes, within 17 weeks (CI 15 to 19) in patients with severe strokes, and within 20 weeks (CI 16 to 24) in patients with very severe strokes. After these time-points, no significant changes occurred. However, a valid prognosis of functional outcome can be made much earlier. Best ADL function was reached by 80% of the patients with initially mild strokes within 3 weeks (CI 2.6 to 3.4), within 7 weeks (CI 6 to 8) of the patients with moderate strokes, and within 11.5 weeks (CI 10 to 13) of the patients with severe and very severe strokes. The time course of neurological recovery followed a pattern similar to that of functional recovery, but preceeded functional recovery by 2 weeks on average. CONCLUSIONS A reliable prognosis can in all stroke patients be made within 12 weeks from stroke onset. Even in patients with severe and very severe strokes, neurological and functional recovery should not be expected after the first 5 months.

Recovery of walking function in stroke patients: The copenhagen stroke study

Time course and degree of the recovery of walking function after stroke and the influence of initial lower extremity (LE) paresis were studied prospectively in a community-based population of 804 consecutive acute stroke patients. Walking function and degree of LE paresis were assessed weekly using the Barthel index and the Scandinavian Neurological Stroke scale, respectively. Initially, 51% had no walking function, 12% could walk with assistance, and 37% had independent walking function. At the end of rehabilitation, 21% had died, 18% had no walking function, 11% could walk with assistance, and 50% had independent walking function. Recovery of walking function occurs in 95% of the patients within the first 11 weeks after stroke. The time and the degree of recovery are related to both the degree of initial impairment of walking function and to the severity of LE paresis, p < .0001. A valid prognosis of walking function in patients with initially no/mild/moderate leg paresis can be made in 3 weeks, and further recovery should not be expected after 9 weeks. A valid prognosis of walking function in patients with initially severe leg paresis or paralysis can be made in 6 weeks, and further improvement of walking function should not be expected later than 11 weeks after stroke.

Recovery of upper extremity function in stroke patients: The Copenhagen stroke study

Time course and degree of recovery of upper extremity (UE) function after stroke and the influence of initial UE paresis were studied prospectively in a community-based population of 421 consecutive stroke patients admitted acutely during a 1-year period. UE function was assessed weekly, using the Barthel Index subscores for feeding and grooming. UE paresis was assessed by the Scandinavian Stroke Scale subscores for hand and arm. The best possible UE function was achieved by 80% of the patients within 3 weeks after stroke onset and by 95% within 9 weeks; in patients with mild UE paresis, function was achieved within 3 and 6 weeks, respectively, and in patients with severe UE paresis within 6 and 11 weeks, respectively. Full UE function was achieved by 79% of patients with mild UE paresis and only by 18% of patients with severe UE paresis. A valid prognosis of UE function can be made within 3 and 6 weeks in patients with mild and severe UE paresis, respectively. Further recovery of UE function should not be expected after 6 and 11 weeks respectively, in these groups of patients.

Acute Stroke With Atrial Fibrillation: The Copenhagen Stroke Study

BACKGROUND Atrial fibrillation (AF) is a common arrhythmia and a major risk factor for stroke. Many physicians remain reluctant to provide stroke prevention by anticoagulant therapy especially for elderly individuals with AF. Using multivariate regression analyses, we studied the characteristics and the prognosis of stroke in patients with AF. METHODS The study is part of the Copenhagen Stroke Study, a prospective, community-based study of 1197 patients with acute stroke treated on a stroke unit from the time of acute admission to the end of rehabilitation. Initial stroke severity was measured by the Scandinavian Neurological Stroke Scale (SSS). Neurological and functional outcomes were evaluated by the SSS and the Barthel Index. RESULTS AF was diagnosed in 18% of the patients. AF increased steeply with age in the stroke population, from 2% in patients < 50 years old, 15% in patients in their 70s, and 28% in patients in their 80s, to 40% in patients > or = 90 years of age. In a multivariate analysis AF was associated with age (odds ratio [OR], 2.0 per 10-year increase; 95% confidence ratio [CI], 1.6 to 2.6), ischemic heart disease (OR, 3.4; 95% CI, 2.4 to 4.8), previous stroke (OR, 1.8; 95% CI, 1.2 to 2.6), and systolic blood pressure (OR, 0.93 per 10-mm Hg increases; 95% CI, 0.88 to 0.99), but not with sex, diabetes, hypertension, previous transient ischemic attack, or silent infarction on computed tomography. Patients with AF had a higher mortality rate (OR, 1.7; 95% CI, 1.2 to 2.5), longer hospital stays (50 days versus 40 days, P < .001), and a lower discharge rate to their own homes (OR, 0.60; 95% CI, 0.44 to 0.85). Neurological and functional outcomes were markedly poorer in patients with AF. Poorer outcome was exclusively explained by initially more-severe strokes. CONCLUSIONS Stroke in patients with AF is generally more severe and outcome markedly poorer than in patients with sinus rhythm. This accentuates the importance of anticoagulant treatment of individuals with AF. A lower blood pressure in the acute stage of stroke may contribute to the increased stroke severity in patients with AF.

Outcome and time course of recovery in stroke. Part I: Outcome. The Copenhagen stroke study

OBJECTIVE To evaluate the outcome of stroke stratified according to both initial stroke severity and initial level of disability. DESIGN Prospective, consecutive, and community based. SETTING A stroke unit of a hospital in Denmark. This setting receives all acute stroke patients admitted from a well-defined catchment area of 239,886 inhabitants within the City of Copenhagen. Acute treatment as well as all stages of rehabilitation are cared for within the stroke unit regardless of age, stroke severity, and premorbid condition. PATIENTS 1197 patients with acute stroke. MAIN OUTCOME MEASURES Primary outcome was measured as death, discharge to nursing home, or to own home. Secondary outcome was measured as neurological deficits and functional disabilities after completed rehabilitation and again 6 months after stroke onset, using the Scandinavian Neurological Stroke Scale and the Barthel Index. RESULTS Stroke was initially very severe in 223 (19%) of the patients, severe in 171 (14%), moderate in 316 (26%), and mild in 487 (41%) patients. Two hundred and fifty (21%) patients died during hospital stay, 177 (15%) were discharged to nursing home, and 770 (64%) patients were discharged to their own home. After completed rehabilitation, 11% of survivors still had severe or very severe neurological deficits, 11% had moderate deficits, and 78% had no or only mild deficits; 20% were severely or very severely disabled, 8% were moderately disabled, 26% were mildly disabled, and 46% had no disability in activities of daily living. Detailed information on outcome stratified according to initial stroke severity/disability also is presented. CONCLUSIONS This study provides a thorough description of the needs for stroke rehabilitation in the community and the amount of postrehabilitation disability in stroke survivors. For outcome prediction, the results can be used as a reliable tool for prognostication of the chances (or risks) of various outcomes in patients characterized by initial degree of stroke severity and/or functional disability using simple, reliable scores in the acute phase of stroke. However, the results should not be used as a guideline for selecting patients for rehabilitation in the acute phase because even the most severe cases regularly experience meaningful improvement during rehabilitation.

Stroke in patients with diabetes : the Copenhagen stroke study

Although diabetes is a strong risk factor for stroke, it is still unsettled whether stroke is different in patients with and without diabetes. This is true for stroke type, stroke severity, the prognosis, and the relation between admission glucose levels and stroke severity/mortality. Methods This community-based study included 1135 acute stroke patients (233 [20%] had diabetes). All patients were evaluated until the end of rehabilitation by weekly assessment of neurological deficits (Scandinavian Stroke Scale) and functional disabilities (Barthel Index). A computed tomographic scan was performed in 83%. Results The diabetic stroke patient was 3.2 years younger than the nondiabetic stroke patient (P<.001) and had hypertension more frequently (48% versus 30%, P<.0001). Intracerebral hemorrhages were six times less frequent in diabetic patients (P=.002). Initial stroke severity, lesion size, and site were comparable between the two groups. However, mortality was higher in diabetic patients (24% versus 17%, P=.03), and diabetes independently increased the relative death risk by 1.8 (95% confidence interval [CI], 1.04 to 3.19). Outcome was comparable in surviving patients with and without diabetes, but patients with diabetes recovered more slowly. Mortality increased with increasing glucose levels on admission in nondiabetic patients independent of stroke severity (odds ratio, 1.2 per 1 mmol/L; CI, 1.01 to 1.42; P=.04). This was not the case in diabetic patients. Conclusions Diabetes influences stroke in several aspects: in age, in subtype, in speed of recovery, and in mortality. Increased glucose levels on admission independently increase mortality from stroke in nondiabetic but not in diabetic patients. The effect of reducing high admission glucose levels in nondiabetic stroke patients should be examined in future trials.

Effect of blood pressure and diabetes on stroke in progression

Progression of acute stroke after arrival at hospital is frequent and the prognosis severe. However, risk factors and mechanisms behind progression are largely unknown. A prospective, community-based study of 868 patients with acute stroke was undertaken to discover factors of importance in the development of stroke in progression. Diagnosis of progression was based on the Scandinavian Neurological Stroke Scale. Patients were divided according to whether progression occurred early (within 36 hours from stroke onset) or late (within the first week from onset). Results were analysed by comparing patients with and without progression. Marked progression developed in 32%. Risk factors for early progression were identified as systolic blood pressure on admission (decreased the relative risk by 0.66 per 20 mm Hg increase, 95% CI 0.55-0.83) and diabetes (increased the relative risk by 1.9, 95% CI 1.1-3.3). Stroke severity was the only risk factor found in late progression (OR 1.4 per 20-point increase in stroke severity, 95% CI 1.1-1.7). These relations were independent of age, sex, blood glucose, heart disease, and other stroke risk factors. Early progression is related to systolic blood pressure and diabetes. Late progression is related to initial stroke severity. Although this study does not prove that a causal relationship exists between systolic blood pressure and the development of early progression, such a relationship would, however, explain our findings.

Aphasia after Stroke: Type, Severity and Prognosis

Aim: To determine the types, severity and evolution of aphasia in unselected, acute stroke patients and evaluate potential predictors for language outcome 1 year after stroke. Methods: 270 acute stroke patients with aphasia (203 with first-ever strokes) were included consecutively and prospectively from three hospitals in Copenhagen, Denmark, and assessed with the Western Aphasia Battery. The assessment was repeated 1 year after stroke. Results: The frequencies of the different types of aphasia in acute first-ever stroke were: global 32%, Broca’s 12%, isolation 2%, transcortical motor 2%, Wernicke’s 16%, transcortical sensory 7%, conduction 5% and anomic 25%. These figures are not substantially different from what has been found in previous studies of more or less selected populations. The type of aphasia always changed to a less severe form during the first year. Nonfluent aphasia could evolve into fluent aphasia (e.g., global to Wernicke’s and Broca’s to anomic), whereas a fluent aphasia never evolved into a nonfluent aphasia. One year after stroke, the following frequencies were found: global 7%, Broca’s 13%, isolation 0%, transcortical motor 1%, Wernicke’s 5%, transcortical sensory 0%, conduction 6% and anomic 29%. The distribution of aphasia types in acute and chronic aphasia is, thus, quite different. The outcome for language function was predicted by initial severity of the aphasia and by the initial stroke severity (assessed by the Scandinavian Stroke Scale), but not by age, sex or type of aphasia. Thus, a scoring of general stroke severity helps to improve the accuracy of the prognosis for the language function. One year after stroke, fluent aphasics were older than nonfluent aphasics, whereas such a difference was not found in the acute phase.

Feasibility and safety of inducing modest hypothermia in awake patients with acute stroke through surface cooling : A case-control study : the Copenhagen Stroke Study

Background and Purpose Hypothermia reduces neuronal damage in animal stroke models. Whether hypothermia is neuroprotective in patients with acute stroke remains to be clarified. In this case-control study, we evaluated the feasibility and safety of inducing modest hypothermia by a surface cooling method in awake patients with acute stroke. Methods We prospectively included 17 patients (cases) with stroke admitted within 12 hours from stoke onset (mean 3.25 hours). They were given hypothermic treatment for 6 hours by the “forced air” method, a surface cooling method that uses a cooling blanket with a flow of cool air (10°C). Pethidine was given to treat compensatory shivering. Cases were compared with 56 patients (controls) from the Copenhagen Stroke Study matched for age, gender, initial stroke severity, body temperature on admission, and time from stroke onset to admission. Blood cytology, biochemistry, ECGs, and body temperature were monitored during hypothermic treatment. Multiple regression analyses on outcome were performed to examine the safety of hypothermic therapy. Results Body temperature decreased from t0=36.8°C to t6=35.5°C (P <0.001), and hypothermia was present until 4 hours after therapy (t0=36.8°C versus t10=36.5°C;P =0.01). Mortality at 6 months after stroke was 12% in cases versus 23% in controls (P =0.50). Final neurological impairment (Scandinavian Stroke Scale score at 6 months) was mean 42.4 points in cases versus 47.9 in controls (P =0.21). Hypothermic therapy was not a predictor of poor outcome in the multivariate analyses. Conclusions Modest hypothermia can be achieved in awake patients with acute stroke by surface cooling with the “forced air” method, in combination with pethidine to treat shivering. It was not associated with a poor outcome. We suggest a large, randomized clinical trial to test the possible beneficial effect of induced modest hypothermia in unselected patients with stroke.