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Biomedical subjects

C Warlow

Publications and source records attributed to C Warlow.

At least 19 recordsLinked to original sources
PubMed1992

Atrial fibrillation and stroke: prevalence in different types of stroke and influence on early and long term prognosis (Oxfordshire community stroke project)

OBJECTIVE: To determine in patients with first ever stroke whether atrial fibrillation influences clinical features, the need to perform computed tomography, and prognosis. DESIGN: Observational cohort study with maximum follow up of 6.5 years. SETTING: Primary care, based on 10 general practices in urban and rural Oxfordshire. SUBJECTS: Consecutive series of 675 patients with first ever stroke registered in the Oxfordshire community stroke project. MAIN OUTCOME MEASURES: Prevalence of atrial fibrillation by type of stroke; effect of atrial fibrillation on case fatality rate and risk of recurrent stroke, vascular death, and death from all causes. RESULTS: Prevalence of atrial fibrillation was 17% (95% confidence interval 14% to 20%) for all stroke types (115/675), 18% (15% to 21%) for cerebral infarction (97/545), 11% (4% to 11%) for primary intercerebral haemorrhage (7/66), and 0% (0 to 11%) for subarachnoid haemorrhage (0/33). For patients with cerebral infarction the 30 day case fatality rate was significantly higher with atrial fibrillation (23%) than with sinus rhythm (8%); the risk of early recurrent stroke (within 30 days) was 1% with atrial fibrillation and 4% with sinus rhythm. In patients who survived at least 30 days the average annual risk of recurrent stroke was 8.2% (5.9% to 10.9%) with sinus rhythm and 11% (6.0% to 17.3%) with atrial fibrillation. CONCLUSIONS: After a first stroke atrial fibrillation was not associated with a definite excess risk of recurrent stroke, either within 30 days or within the first few years. Survivors with and without atrial fibrillation had a clinically important absolute risk of further serious vascular events.

Aged↗
PubMed1992

Diurnal variation in incidence of stroke: Oxfordshire community stroke project.

OBJECTIVE: To determine whether diurnal variation occurs in the onset of stroke. DESIGN: Community based study over four years. SETTING: Oxfordshire, United Kingdom. SUBJECTS: 105,000 people, of whom 675 had a first ever stroke. 545 had a cerebral infarction, 66 had primary intracerebral haemorrhage, 33 had subarachnoid haemorrhage, and in 31 the type of stroke was not known. MAIN OUTCOME MEASURES: Time of stroke and degree of activity at onset. RESULTS: In the 578 patients for whom it was known whether onset occurred while asleep or awake, the proportion with onset during sleep was 25% (135/545) for cerebral infarction, 17% (11/66) for primary intracerebral haemorrhage, and 0% (0/33) for subarachnoid haemorrhage. This difference persisted if patients in whom it was not known whether they were asleep or awake at onset were classed as asleep. For all stroke types together there was a significant (chi 2 = 218.7, p less than 0.001) diurnal variation with a morning peak between 0800 and 1000, which persisted even after allowing for strokes first noted on waking by redistributing the hour of onset through the preceding eight hours (chi 2 = 47, p less than 0.001). A significant diurnal variation was also found in the onset of cerebral infarction (peak 0800-1000, chi 2 = 208.4, p less than 0.001). Fewer patients had other forms of stroke and the diurnal variations for primary intracerebral haemorrhage (peak 1000-1200) and subarachnoid haemorrhage (peaks 0800-1000 and 1800-2000) were not significant. There seemed to be a second smaller peak for all types of stroke. CONCLUSIONS: All types of stroke are most likely to occur after waking in the morning. The cause of the circadian variation requires further study.

Cerebral Hemorrhage↗
PubMed1992

Migraine aura without headache: transient ischaemic attack or not?

Patients with "migraine aura without headache" can be separated from those with transient ischaemic attacks (TIA) on the basis of the onset of symptoms, which is generally gradual and which spread or intensify over minutes or hours, and from the typical migrainous nature of their visual symptoms. Fifty cases were prospectively identified and these were compared with 50 age matched patients with a TIA. Surprisingly, there were no significant differences in the prevalence of vascular risk factors and diseases in the two groups although those with TIAs tended to have more. Only one patient with "migraine aura without headache" suffered a subsequent vascular event (a myocardial infarction). Three patients with TIAs had strokes and two others died from vascular disease. Although the results are not conclusive, they do suggest that patients with the clinical characteristics of "migraine aura without headache" have a low risk of subsequent vascular events, lower than those with TIAs, despite perhaps having similar prevalence of vascular risk factors. Although their risk factors should be treated, patients with "migraine aura without headache" should be reassured and not subjected to inappropriate and potentially hazardous investigations and treatment.

Adult↗
PubMed1991

Fibrinogen and lipid concentrations as risk factors for transient ischaemic attacks and minor ischaemic strokes.

OBJECTIVES: To determine whether fibrinogen and lipid concentrations are risk factors for ischaemic stroke. DESIGN: Case-control study with a population based comparison within the overall study. SETTING: Oxfordshire community stroke project and a neurology clinic. SUBJECTS: 105 patients who had a transient ischaemic attack or minor ischaemic stroke and 352 randomly chosen controls matched for age and sex from the same general practitioners as the incident cases. 52 controls were ineligible or refused interview. 104 cases and 241 controls gave blood samples for analysis. MAIN OUTCOME MEASURES: Response to structured questionnaire, height, weight, blood pressure, and serum concentrations of fibrinogen and lipids. RESULTS: Adjusted for other variables, odds ratios of ischaemic stroke were 1.78 (95% confidence interval 0.91 to 3.48; p = 0.09) [corrected] for fibrinogen concentrations greater than 3.6 g/l; 1.73 (0.90 to 3.29; p = 0.09) [corrected] for total cholesterol concentrations greater than 6.0 mmol/l; 1.34 (0.69 to 2.61; p greater than 0.4) for low density lipoprotein cholesterol concentrations greater than 3.5 mmol/l; and 0.32 (0.15 to 0.69; p = 0.002) for high density lipoprotein cholesterol concentration greater than 1.2 mmol/l. Similar results emerged comparing only community derived cases with transient ischaemic attacks and controls. The effects of fibrinogen, total cholesterol, and high density lipoprotein cholesterol were significant in a test of trend after adjusting for all other variables in the study (chi 2 = 4.14, p less than 0.05; chi 2 = 4.31, p less than 0.05, and chi 2 = 12.15, p greater than 0.001, respectively). History of ischaemic heart disease and hypertension were the only other variables that showed significance, though both lost significance after adjustment (2.06, p = 0.08 and 1.53, p = 0.2, respectively). CONCLUSIONS: Fibrinogen and lipids are important risk factors for ischaemic stroke. The pattern of changes mirrors that found in ischaemic heart disease.

Adult↗
PubMed1991

Strategy for stroke.

Explore the source record for details and available documents.

Cerebrovascular Disorders↗
PubMed1991

Classification and natural history of clinically identifiable subtypes of cerebral infarction.

We describe the incidence and natural history of four clinically identifiable subgroups of cerebral infarction in a community-based study of 675 patients with first-ever stroke. Of 543 patients with a cerebral infarct, 92 (17%) had large anterior circulation infarcts with both cortical and subcortical involvement (total anterior circulation infarcts, TACI); 185 (34%) had more restricted and predominantly cortical infarcts (partial anterior circulation infarcts, PACI); 129 (24%) had infarcts clearly associated with the vertebrobasilar arterial territory (posterior circulation infarcts, POCI); and 137 (25%) had infarcts confined to the territory of the deep perforating arteries (lacunar infarcts, LACI). There were striking differences in natural history between the groups. The TACI group had a negligible chance of good functional outcome and mortality was high. More than twice as many deaths were due to the complications of immobility than to direct neurological sequelae of the infarct. Patients in the PACI group were much more likely to have an early recurrent stroke than were patients in other groups. Those in the POCI group were at greater risk of a recurrent stroke later in the first year after the index event but had the best chance of a good functional outcome. Despite the small anatomical size of the infarcts in the LACI group, many patients remained substantially handicapped. The findings have important implications for the planning of stroke treatment trials and suggest that various therapies could be directed specifically at the subgroups.

Age Factors↗
PubMed1991

The United Kingdom transient ischaemic attack (UK-TIA) aspirin trial: final results.

From 1979-85, 2435 patients with a transient ischaemic attack or minor ischaemic stroke were randomly allocated to receive long term "blind" treatment with aspirin 600 mg twice daily (n = 815), aspirin 300 mg once daily (n = 806) or placebo (n = 814). No patient was lost to follow up. The "intention to treat" comparison included all the serious vascular events and deaths which occurred before the end of the follow up period on 30 September 1986. There was no difference in efficacy between the 300 mg and 1200 mg daily doses of aspirin, but the lower dose was undoubtedly less gastrotoxic. Also, there was no definite difference in the response of males and females to aspirin. The odds of suffering a major stroke, myocardial infarction or vascular death were 15% less in the combined aspirin groups compared with the placebo group (95% confidence interval 29% reduction to 3% increase in odds) which is compatible with the continuing overview of all the similar trials of antiplatelet drugs where the relative reduction in odds was 25%. There was no statistically significant reduction in the likelihood of either disabling major stroke and vascular death or vascular death occurring.

Aged↗
PubMed1991

Mood disorders in the year after first stroke.

An unselected community sample of 128 patients were studied over the 12 months after their first stroke, and compared with a control sample of subjects from the general population. Psychiatric status was assessed using the PSE and BDI. Symptoms of mood disorder were commoner in the stroke patients than the controls, but the differences were not substantial and had largely disappeared by 12 months. Psychiatric problems encountered included agoraphobia, social withdrawal, apathy and self-neglect, irritability and pathological emotionalism. While there was a high cumulative incidence of psychiatric disorder, little of it persisted: only two cases of major depression were present for the whole 12 months. We believe undue emphasis has been placed in the recent literature on major depression as a specific syndrome following stroke.

Adolescent↗
PubMed1990

Computed tomography in patients with transient ischaemic attacks: when is a transient ischaemic attack not a transient ischaemic attack but a stroke?

In a prospective community-based study, 184 patients with transient ischaemic attacks (TIAs) were identified from a study population of about 105,000 between 1981 and 1986. Computed tomography (CT) was attempted in all those with cerebral ischaemic attacks (n = 152, 83%); patients with amaurosis fugax only (n = 32, 27%) were not scanned routinely. Scans were obtained in 120 (79%) of those with cerebral attacks and 12 (38%) of those with amaurosis fugax. The scans were reported by a neuroradiologist who was blinded to the patients' clinical features. Of 120 (27%:95% confidence interval 19-35) scans in patients with cerebral attacks, 32 showed a focal area of hypodensity or cortical loss, but in only 14 (12%:95% confidence interval 6-18) was this in an area of the brain appropriate to the patients' symptoms. There were no significant differences in the clinical features, the duration of attacks or the prognosis (i.e., risk of death, stroke or myocardial infarction) of patients with and without ischaemic lesions on CT. It is concluded that patients with clinically definite TIAs who have a presumed ischaemic and appropriately sited lesion on CT should not be re-classified as having had a stroke.

Aged↗
PubMed1990

The relationship between intellectual impairment and mood disorder in the first year after stroke.

In a community-based study of patients with a first-ever stroke, intellectual impairment (as defined by scores on a common screening test for dementia, the Mini-Mental State Examination) was found in 26% at 1 month post-stroke, and in 21% at 6 and 12 month follow-up. Low scores on the screening test were associated with greater age, physical disability before the stroke, larger stroke lesion volumes as measured on CT scan, and non-stroke changes such as atrophy and white matter low attenuation on the CT scan. There was a negative correlation between scores on the Mini-Mental State Examination and symptom levels on two measures of mood disorder. However, there was no evidence of a specific relationship between major depression and low scores on the Mini-Mental State. We examined various aspects of the relationship between mood symptoms and low scores on the Mini-Mental State, but found no evidence to support the suggestion that this relationship represented an example of depressive pseudodementia. We discuss the significance of our findings for clinical psychiatry and neuropsychology.

Adolescent↗
PubMed1990

Mood disorders in long-term survivors of stroke: associations with brain lesion location and volume.

Sixty surviving patients from a community-based stroke register who had CT scan evidence of a single brain lesion and neurological signs appropriate to it were interviewed three to five years following their first-ever stroke. Mood disorder (anxiety and depression), physical disability, and intellectual impairment were assessed using standardized measures. The position and volume of the brain lesion was determined from CT scans performed soon after the stroke. The prevalence of depressive disorder was lower in this sample than that reported in previous studies (DSM-IIIR major depression 8.3%; all DSM-IIIR depressive disorders 18.3%). Reports by other workers for an association of depressive disorder either with left-sided brain lesions, or with anteriorly placed lesions in the left cerebral hemisphere, were not supported. Neither was there evidence of a correlation between symptom score and proximity of the lesion to the anterior pole of the left cerebral hemisphere. Psychiatric symptom scores were however greater with larger volume brain lesions. Anxiety disorders, especially agoraphobia, were relatively common (20% if diagnosed in the presence of depressive disorder), but were not related to lesion location or volume.

Activities of Daily Living↗
PubMed1990

Mood disorders after stroke and their relation to lesion location. A CT scan study.

In a community-based study of stroke survivors, we identified 73 consecutive patients with a stroke, the first ever in a lifetime, who had a CT scan which showed a neurologically appropriate single stroke lesion, and who did not have a psychiatric disorder in the year preceding the stroke. A detailed follow-up study of these patients using standardized psychiatric assessments failed to confirm a number of recent claims about poststroke depressive disorders. We found no evidence that left-sided lesions were associated with more severe or persistent depressive symptoms, or that right-sided lesions were associated with hypomania. The DSM III syndrome of major depression was much less common than has previously been reported, and was not specifically associated with lesions placed anteriorly in the left hemisphere. There was a weak correlation between mood symptom scores and the proximity of the stroke lesion to the frontal pole of the hemisphere, but no evidence of a difference between right and left hemisphere strokes in the nature of the relationship between lesion distribution and mood symptoms. We suggest that previous studies have different findings because of differences in the conventions applied to the definition and measurement of psychiatric disorders after stroke, and because other studies have concentrated on selected inpatient populations.

Adolescent↗
PubMed1990

A prospective study of acute cerebrovascular disease in the community: the Oxfordshire Community Stroke Project--1981-86. 2. Incidence, case fatality rates and overall outcome at one year of cerebral infarction, primary intracerebral and subarachnoid haemorrhage.

The age and sex specific incidence rates for cerebral infarction, primary intracerebral haemorrhage and subarachnoid haemorrhage in a population of approximately 105,000 are presented. Over four years 675 patients with a first-ever stroke were registered with the Oxfordshire Community Stroke Project. The pathological diagnosis was confirmed by computerised tomography (CT) scan, necropsy or lumbar puncture (cases of subarachnoid haemorrhage only) in 78% of cases and a further 17% were diagnosed according to the Guy's Hospital Stroke Diagnostic Score. The proportion of all first-ever strokes by pathological type was: cerebral infarction 81% (95% confidence interval 78-84), primary intracerebral haemorrhage 10% (8-12), subarachnoid haemorrhage 5% (3-7) and uncertain type 5% (3-7). These proportions are similar to other community-based studies. The overall 30 day case fatality rate was 19% (16-22), that for cerebral infarction being 10% (7-13), primary intracerebral haemorrhage 50% (38-62) and subarachnoid haemorrhage 46% (29-63). One year post stroke 23% (19-27) with cerebral infarction were dead and 65% (60-70) of survivors were functionally independent. The figures for primary intracerebral haemorrhage were 62% (43-81) dead and 68% (50-86) of survivors functionally independent and for subarachnoid haemorrhage were 48% (24-72) dead and 76% (56-96) of survivors functionally independent. There are important differences between these rates and those from other sources possibly due to more complete case ascertainment in our study. Nevertheless, the generally more optimistic early prognosis in our study, particularly for cases of cerebral infarction, has important implications for the planning of clinical trials and for the expected impact that any treatment might have on the general population.

Adolescent↗
PubMed1990

The frequency, causes and timing of death within 30 days of a first stroke: the Oxfordshire Community Stroke Project.

In a prospective, community-based study of 675 consecutive patients with a first-ever stroke, of whom over 90% had computed tomography (CT) and/or necropsy examinations, 129 deaths occurred within 30 days of the onset of symptoms, a case fatality rate (CFR) of 19%. The 30 day CFR for patients with cerebral infarction was 10% (57 of 545, for primary intracerebral haemorrhage 52% (34 of 66), for subarachnoid haemorrhage 45% (15 of 33) and for those of uncertain pathological type 74% (23 of 31). The CFR for patients who had been functionally dependent pre-stroke was 33% compared with 17% for those who had been independent pre-stroke. The age-adjusted relative risk of death for patients who had been functionally dependent pre-stroke was not significantly greater (1.8, 95% confidence interval 0 to 4.3). There was a significant trend for CFR to increase with age (Chi square for trend = 4.0, p less than 0.05). This relationship was found in those patients who had been functionally independent prestroke (Chi square for trend = 7.9, p less than 0.005) but not in those who had been dependent pre-stroke (Chi square for trend = 0.5, NS). The pattern of increasing CFR with increasing age amongst those who had been independent prestroke was seen particularly in patients with cerebral infarction (Chi square for trend = 8.6, p less than 0.005). The age-adjusted relative risk of death for patients with cerebral infarction who had been functionally dependent pre-stroke was 2.2 (95% confidence interval 1.2 to 4.1). Fifty three percent of all deaths within 30 days of stroke were due to the direct neurological sequelae of the stroke. Patients with primary intracerebral or subarachnoid haemorrhages were significantly more likely to die in this way than those with cerebral infarction (relative risk 4.1; 95% confidence interval 3.4-4.9) and 56% of such deaths occurred within 72 hours of onset. In patients with cerebral infarction, 51% of deaths were due to complications of immobility (for example, pneumonia, pulmonary embolism) and these were more likely to occur after the first week. These findings have implications for clinical practice and the planning of clinical trials.

Aged↗
PubMed1990

Life events and difficulties preceding stroke.

Life events and difficulties were recorded for the year before stroke, using a standardised semi-structured interview, in 113 surviving patients seen after their first ever in a lifetime stroke. An age and sex-matched control group (n = 109) was also interviewed about the preceding year. The stroke patients reported fewer non-threatening events and events with only a short-term threat, while difficulties were reported with equal frequency by the two groups. However, events which were severely threatening in the long-term were significantly more common in the stroke patients (in the 52 weeks before stroke 26% versus 13%, odds ratio 2.3, 95% confidence interval 1.1-4.9). The increased rate was apparent throughout the year and not just in the weeks immediately before stroke onset. The number of stroke patients experiencing severe events in the follow up year fell to the level found in the control group. Recognised risk factors for stroke were found equally in those patients with and without severe events before onset, except that hypertension was rather less common in the patients who had experienced a severe event. It therefore appears that severe life events may be one of the determinants of stroke onset.

Adolescent↗