Primary intracerebral and aneurysmal subarachnoid hemorrhage in Izumo City, Japan. Part I: incidence and seasonal and diurnal variations

Incidence But Not Severity of Intracerebral Hemorrhage Shows a Strong Pattern of Seasonal Variation

BACKGROUND

A strong risk factor for intracerebral hemorrhage (ICH) is elevated arterial blood pressure, which is known to vary by season, with highest values in winter months. The objective was to assess seasonal trends of ICH incidence, clinical severity, and case fatality according to demographic and clinical characteristics.

METHODS

This study was conducted on adult patients hospitalized for ICH between 2003 and 2022. Cases were identified from a stroke inpatient quality assurance registry covering the entire Federal State of Hesse, Germany. Population data were derived from the Hessian Bureau of Statistics. Incidence rates (IRs) per 100 000 person-years of ICH, recorded with 4-digit International Statistical Classification of Diseases, Tenth Revision, German Modification (ICD-10-GM) I61.x codes, were estimated by season, calendar month, and bleeding location. Seasonal variations and subgroup analyses were tested using Poisson distribution and the Wald test.

RESULTS

A total of 33 444 patients were included (mean age, 72.4±13.6 years, 52% men). ICH IR correlated with the season of occurrence, demonstrating a peak in winter (IR winter, 34.6 [95% CI, 33.9-35.4], IR summer, 29.4 [95% CI, 28.7-30.1]; P<0.01). Seasonal variation was equally present in men and women but was more pronounced in older compared with younger patients (peak at age 60-90 years; P<0.01). IR showed seasonal variation both for cortical and subcortical bleeding locations (P<0.01). Clinical severity and case fatality did not vary between seasons (mean, 24.3±0.8%).

CONCLUSIONS

This large cohort study demonstrates a seasonal incidence peak of ICH in winter. Whether ICH can be prevented by better control of arterial blood pressure in seasons with expected incidence peaks will require further studies.

Subarachnoid Haemorrhage Incidence Pattern Analysis with Circular Statistics

Knowledge about biological rhythms of diseases may not only help in understanding the pathophysiology of diseases but can also help health service policy makers and emergency department directors to allocate resources efficiently. Aneurysmal subarachnoid haemorrhage (SAH) has high rates of morbidity and mortality. The incidence of SAH has been attributed to patient-related factors such as characteristics of aneurysms, smoking, and hypertension. There are studies showing that the incidence of aneurysmal SAH appears to behave in periodic fashions over long time periods. However, there are inconsistencies in the literature regarding the impact of chronobiological factors such as circadian, seasonal, and lunar cycle factors on the occurrence of SAH. In this study, we focused on the analysis of a temporal pattern of SAH (infradian rhythms) with a novel approach using circular statistical methods. We aimed to see whether there is a circular pattern for the occurrence of SAH at all and if so, whether it can be related to known temporal patterns based on available literature. Our study did not support the notion that aneurysmal subarachnoid haemorrhages occur on any specific day in a cycle with specific lengths up to 365 days including specific weekdays, full moon, equinoxes, and solstices. Hence, we found no relationship between SAH incidence and timing. Study in larger populations using similar circular statistical methods is suggested.

Recent Declining Trend of Incidence Rate of Subarachnoid Hemorrhage in Shimane, Japan: The Japan Incidence of Subarachnoid Hemorrhage (JIS) Study

The “Izumo Study” revealed the incidence rate of subarachnoid hemorrhage (SAH) in Izumo City, Shimane Prefecture, Japan, from 1980 to 1998. However, no study has been published regarding the incidence of SAH in Shimane Prefecture after 1998. Most studies reporting the incidence of SAH in Japan have been conducted before 2000, although a few have been reported after 2000. This study aimed to assess the estimated age-adjusted incidence rate (AAIR) of SAH in Shimane Prefecture after 1998, following the Izumo Study. A retrospective study was conducted to identify the estimated AAIR of SAH in Shimane Prefecture, using the age-adjusted SAH mortality rate for this population from 1999 to 2017 and assuming that the case-fatality rate of SAH decreased by 0.7% annually from 45% in 1999 to 32.4% in 2017. We used linear regression analysis for trend to the estimated AAIR of SAH. Sensitivity analyses were also conducted by various case-fatality rates of SAH using assuming case-fatality rate based on previous reports. The estimated AAIR of SAH in Shimane Prefecture declined from 33.6 (95% confidence interval [CI]: 29.7-37.9) per 100,000 person-years in 1999, by 26.5%, to 24.7 (95% CI: 21.4-28.5) in 2017 (p < 0.01, r = 0.58). Declining trend of incidence rate of SAH in Shimane Prefecture from 1999 to 2017 was confirmed in this study.

Epidemiology of intracerebral hemorrhage: A systematic review and meta-analysis

Background

Intracerebral hemorrhage (ICH) is associated with high mortality and disability rates. This study aimed to investigate the relationship between sex, age, study year, risk factors, bleeding site, median year of study, and the incidence of ICH.

Method

Literature on the incidence of ICH published on 1 January 1980 and 1 January 2020, was systematically retrieved from PubMed and Embase databases. The random-effects model and subgroup analysis were used to explore the relationship between the incidence of ICH and different ages, sex, bleeding sites, and risk factors.

Results

We summarized the epidemiological changes in ICH in the past 40 years according to 52 studies and found that the total incidence of ICH is 29.9 per 100,000 person-years (95% CI: 26.5–33.3), which has not decreased worldwide. The incidence of ICH in the Asian population is much higher than in other continents. In addition, the incidence of ICH increases with age and differs at the 85-year-old boundary. Men are more likely to develop ICH than women, and the basal ganglia region is the most common area for ICH. Of the 10 risk factors examined in this study, those with hypertension had the highest incidence of ICH, followed by those with excessive alcohol consumption and heart disease.

Conclusion

The prevention and treatment of ICH still need to be improved continuously according to age, sex, risk factors, and other factors, and targeted and normative strategies should be gradually developed in the future.

Chronobiological Patterns of Aneurysmal Subarachnoid Hemorrhage in Central China

Background:

Aneurysmal subarachnoid hemorrhage (aSAH) is an acute and sometimes fatal cerebrovascular disease. The chronobiological patterns of aSAH are still unclear worldwide. This 15-year time-series study aims to clarify the chronobiological patterns including seasonal, monthly, weekly, and circadian distributions of aSAH.

Methods:

We retrospectively analyzed the medical records of aSAH patients in central China. To investigate seasonal and weekly distributions, we used the χ2 goodness-of-fit test to analyze the uniformity of the onset time. To explore monthly and circadian distributions, we established Fourier models to show the rhythmicity in chronobiological patterns. Subgroup analyses were conducted to assess the impact of age, gender, hypertension statuses, and aneurysmal characteristics (number, size, and location) on the chronobiological patterns of aSAH.

Results:

A total of 1469 patients with aSAH were recruited in the study. The seasonal and monthly distribution exhibited significantly higher incidence in winter and January/December and lower incidence in summer and July. The weekly distribution of aSAH onset showed no significant uneven variation. The circadian distribution of aSAH exhibited a significant pattern (p = 0.0145), with a morning peak around 8:00, and a late afternoon peak at 16:00–20.00. The circadian rhythmicity varied in subgroups of different ages, genders, and aneurysmal locations.

Conclusion:

The occurrence of aSAH exhibits significant circannual and circadian patterns among the Chinese population. Patients with aSAH of different ages, genders, and aneurysmal locations would present different chronobiological patterns.

Serum GFAP for stroke diagnosis in regions with limited access to brain imaging (BE FAST India)

Introduction

Despite a high burden of stroke, access to rapid brain imaging is limited in many middle- and low-income countries. Previous studies have described the astroglial protein GFAP (glial fibrillary acidic protein) as a biomarker of intracerebral hemorrhage. The aim of this study was to test the diagnostic accuracy of GFAP for ruling out intracranial hemorrhage in a prospective cohort of Indian stroke patients.

Patients and methods

This study was conducted in an Indian tertiary hospital (Christian Medical College, Ludhiana). Patients with symptoms suggestive of acute stroke admitted within 12 h of symptom onset were enrolled. Blood samples were collected at hospital admission. Single Molecule Array technology was used for determining serum GFAP concentrations.

Results

A total number of 155 patients were included (70 intracranial hemorrhage, 75 ischemic stroke, 10 stroke mimics). GFAP serum concentrations were elevated in intracranial hemorrhage patients compared to ischemic stroke patients [median (interquartile range) 2.36 µg/L (0.61–7.16) vs. 0.18 µg/L (0.11–0.38), p < 0.001]. Stroke mimics patients had a median GFAP serum level of 0.14 µg/L (0.09–0.26). GFAP values below the cut-off of 0.33 µg/L (area under the curve 0.871) ruled out intracranial hemorrhage with a negative predictive value of 89.7%, (at a sensitivity for detecting intracranial hemorrhage of 90.0%).

Discussion

The high negative predictive value of a GFAP test system allows ruling out patients with intracranial hemorrhage.

Conclusion

In settings where immediate brain imaging is not available, this would enable to implement secondary prevention (e.g., aspirin) in suspected ischemic stroke patients as soon as possible.

Implications of Circadian Rhythm in Stroke Occurrence: Certainties and Possibilities

Stroke occurrence is not randomly distributed over time but has circadian rhythmicity with the highest frequency of onset in the morning hours. This specific temporal pattern is valid for all subtypes of cerebral infarction and intracerebral hemorrhage. It also correlates with the circadian variation of some exogenous factors such as orthostatic changes, physical activity, sleep-awake cycle, as well as with endogenous factors including dipping patterns of blood pressure, or morning prothrombotic and hypofibrinolytic states with underlying cyclic changes in the autonomous system and humoral activity. Since the internal clock is responsible for these circadian biological changes, its disruption may increase the risk of stroke occurrence and influence neuronal susceptibility to injury and neurorehabilitation. This review aims to summarize the literature data on the circadian variation of cerebrovascular events according to physiological, cellular, and molecular circadian changes, to survey the available information on the chronotherapy and chronoprophylaxis of stroke and its risk factors, as well as to discuss the less reviewed impact of the circadian rhythm in stroke onset on patient outcome and functional status after stroke.

Circadian variations in the occurrence of first-ever intracerebral hemorrhage from different sources of income: a hospital-based cross-sectional study

BACKGROUND

The onset time of intracerebral hemorrhage (ICH) may be closely related to the working style and living habits of people, which are determined by different income sources in China. Therefore, the purpose of our study was to investigate the Circadian Variations in the occurrence of ICH from different sources of income.

METHODS

This retrospective study enrolled 4,327 patients with first-ever ICH. Based on the time of day at which the patients developed symptoms, the classifiable onset time was assigned to one of eight three-hour intervals. And based on different income sources, they were categorized into three groups: Farmers, Wage-earners, and Freelancers. Demographic and risk factors of patients were then summarized, and the circadian variation of the 3 groups of patients' known time of onset and those stratified by sex and age were analyzed.

RESULTS

The frequency of ICH onset exhibited significant circadian variation among the 3 income groups, demonstrating a bimodal distribution in the daytime, with a nadir during the night (all P < 0.001). Three groups showed a significant initial peak between 06:01 and 09:00, and the same peak was observed in their subgroups of sex and age. In the 3 income source groups, there was a smaller second peak that between 15:01 and 18:00 for Farmers and Wage-earners and 18:01 and 21:00 for Freelancers. After stratification by sex and age, the second peak was between 18:01 and 21:00 for female in Farmers, female in Freelancers, under 65 years of age in Wage-earners and 65 years or older in Freelancers, while 15:01 and 18:00 for the other groups.

CONCLUSIONS

Different circadian variations of ICH onset time are found in patients with different income sources in southwest China's Chongqing Municipality cohort. Moreover, the frequency and distribution pattern of peak hours may be closely related to the working style and living habits of people with different income sources.

Aneurysmal subarachnoid hemorrhage: Geography has a role

Background:

The incidence of aneurysmal subarachnoid hemorrhage (SAH) reported in the literature has been very variable. Many authors have proposed a geographical variation in incidence, but others have dismissed this as being due to insufficient pickup rate. In India also, these arguments abound. Our aim was to find out if geographical variations exist in the incidence of aneurysmal SAH and whether the incidence of aneurysmal SAH was truly less in India as compared to the literature.

Materials and Methods:

The data from 182 consecutive cases of SAH admitted to this institution between March 1999 and July 2003 were used for this study.

Results:

There were 84 females and 98 males in this study. More than half of the patients were hypertensive. Four-vessel angiogram was done in 113 patients, of whom sixty-nine were normal. Of the patients with hypertension, 92% had angiogram done and was normal in 65% of cases.

Conclusions:

This study from a large general hospital in South India shows that the incidence of aneurysmal rupture as a cause of SAH is much less in India and probably in the Indian subcontinent in comparison with the western literature thus demonstrating geographical variations in the incidence of aneurysmal SAH. It is concluded that aneurysms as a cause of SAH are still less in India and that we are not missing anything. This study is intended to help target scarce, expensive resources toward more common pathologies.

Mean air temperature as a risk factor for stroke mortality in São Paulo, Brazil

In Brazil, chronic diseases account for the largest percentage of all deaths among men and women. Among the cardiovascular diseases, stroke is the leading cause of death, accounting for 10% of all deaths. We evaluated associations between stroke and mean air temperature using recorded mortality data and meteorological station data from 2002 to 2011. A time series analysis was applied to 55,633 mortality cases. Ischemic and hemorrhagic strokes (IS and HS, respectively) were divided to test different impact on which subgroup. Poisson regression with distributed lag non-linear model was used and adjusted for seasonality, pollutants, humidity, and days of the week. HS mortality was associated with low mean temperatures for men relative risk (RR) = 2.43 (95% CI, 1.12-5.28) and women RR = 1.39 (95% CI, 1.03-1.86). RR of IS mortality was not significant using a 21-day lag window. Analyzing the lag response separately, we observed that the effect of temperature is acute in stroke mortality (higher risk among lags 0-5). However, for IS, higher mean temperatures were significant for this subtype with more than 15-day lag. Our findings showed that mean air temperature is associated with stroke mortality in the city of São Paulo for men and women and IS and HS may have different triggers. Further studies are needed to evaluate physiologic differences between these two subtypes of stroke.

Daily Variation in the Occurrence of Different Subtypes of Stroke

Three thousand two hundred and ninety-eight patients admitted to our Stroke Unit with hemorrhagic, large artery atherosclerosis, cardioembolic, small-vessel occlusion, and undetermined etiology-cryptogenic strokes were included in the study. The circadian variability in onset in each stroke subgroup and the associations with various risk factors were analyzed. In each subgroup, a significant minority of patients suffered from stroke during sleep. In the ischemic group, hypercholesterolemia, paroxysmal atrial fibrillation, and previous myocardial infarction facilitated the onset during waking. During waking, stroke onset was significantly higher in the morning compared to the afternoon both in the hemorrhagic and in the ischemic type. In hemorrhagic stroke, a previous stroke was associated with a lower early morning occurrence. In large artery atherosclerosis stroke, males were at higher risk of early morning occurrence (p < 0.01). In small-vessel occlusion stroke, hypertension is significantly more present in the morning compared to the afternoon onset (p < 0.005). Circadian patterns of stroke onset were observed both in hemorrhagic and in ischemic stroke, irrespective of the ischemic subgroup. In all groups, stroke was more likely to occur during waking than during sleep and, in the diurnal period, during morning than during afternoon. Moreover, sex and some clinical factors influence the diurnal pattern.

A Community-Based Study of the Correlation of Hemorrhagic Stroke Occurrence with Meteorologic Factors

BACKGROUND

Meteorologic variations may affect hemorrhagic stroke. Thus, the aim of this study was to explore the correlation of daily meteorologic factors with increased incidence of hypertensive intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH) in a community-based study.

METHODS

In a span of 2 years, 735 patients suffering from hypertensive ICH or SAH were enrolled in the study in Fularji District, Heilongjiang Province, China. Daily meteorologic data were obtained from the Bureau of Meteorology of Qiqihar. Daily meteorologic parameters with and without events were compared with hypertensive ICH and SAH, respectively. Logistic regression was used to assess the correlation of meteorologic factors with hypertensive ICH and SAH.

RESULTS

Daily mean ambient temperature (AT) was statistically associated with the onset of primary hypertensive ICH (odds ratio [OR], .983; P < .001) and SAH (OR, .984; P = .046). After adjustment with AT variations, the occurrence of primary hypertensive ICH was not only influenced by daily mean AT (P = .0004) but also by the interaction between the mean temperature and its variation (P = .0082). Interestingly, there was no statistical association between meteorologic factors and recurrent hypertensive ICH.

CONCLUSIONS

The higher incidence of primary hypertensive ICH in the late spring and early autumn was because of the influence of daily mean AT and its variation. When temperature changed, suddenly dropping in the hot weather or rising in the cold weather, the incidence of primary hypertensive ICH was also increased. Conversely, the incidence of SAH increased during days with lower temperature.

Outcomes after Early Anticonvulsant Discontinuation in Aneurysmal Subarachnoid Hemorrhage

Background:

Empiric use of anticonvulsant (AED) for seizure prophylaxis in aneurysmal subarachnoid hemorrhage (SAH) remains controversial and may be associated with worse SAH outcome. We determined the safety and feasibility of early discontinuation of empiric AED in a select cohort of SAH patients.

Methods:

In a cohort of 166 consecutive SAH patients, a subset underwent early AED discontinuation if they were awake and following commands after aneurysm treatment. We examined the effect of AED discontinuation on seizure incidence, mortality and functional outcome at discharge using logistic regression and validated results using 70%-30% data partition.

Results:

Seventy-three subjects underwent AED discontinuation. Patient groups had similar gender, age, Fisher grade, incidence of craniotomy, vasospasm, ischemic infarct, intraventricular and intraparenchymal hemorrhages. Hunt-Hess (HH) grade were lower in AED-discontinuation group. Clinical or electrographic seizure occurred in 1/93 (1%) patients on AED and 0/73 patient in AED-discontinuation group. Crude mortality was 24% in patients on AED and 2.7% off AED. After adjusting for age, HH grade, vasospasm, ischemic infarct, intracerebral, and intraventricular hemorrhage, AED discontinuation remains independently associated with lower mortality and higher odds of discharge to home (p=0.0002). AED use is not associated with angiographic vasospasm on exploratory analysis.

Conclusion:

AED discontinuation in SAH patients who are awake and following commands post aneurysm treatment is safe, feasible, and associated with better outcome at hospital discharge. A larger, prospective study is necessary to determine if empiric AED use in SAH leads to poorer functional status.

The association between meteorological parameters and aneurysmal subarachnoid hemorrhage: a nationwide analysis

Prior research has suggested that regional weather patterns impact the risk of rupture of cerebral aneurysms, but the findings in the literature have been inconsistent. Furthermore, no nationwide analysis to date has examined the association between meteorological factors and the post-procedural outcomes of patients after the treatment for ruptured cerebral aneurysms. The purpose of this study was to use a nationwide sample to analyze the association between specific meteorological parameters—temperature, precipitation, sunlight, and humidity—and hospital admission rate for and outcome after aneurysmal subarachnoid hemorrhage. Patients were identified using the Nationwide Inpatient Sample (2001–2010): Those with an ICD-9 diagnosis code for subarachnoid hemorrhage and a procedural code for aneurysm repair were included. Climate data were obtained from the State of the Climate Report 2010 released by the National Climatic Data Center. Multivariate regression models were constructed to analyze the association between average state monthly temperature, precipitation, and percent possible sunlight, as well as relative morning humidity and both monthly hospital admission rate, adjusted for annual state population in millions, and in-hospital mortality. 16,970 admissions were included from 723 hospitals across 41 states. Decreased daily sunlight and lower relative humidity were associated with an increased rate of admission for ruptured cerebral aneurysms (p<0.001), but had no association with differential inpatient mortality. No significant changes in these observed associations were seen when multivariate analyses were constructed. This is the first nationwide study to suggest that decreased sunlight and lower relative humidity are associated with admission for ruptured cerebral aneurysms. While it has been postulated that external atmospheric factors may cause hormonal and homeostatic changes that impact the risk of rupture of cerebral aneurysms, additional research is needed to confirm and further understand these relationships.

Gender-related protection from or vulnerability to severe CNS diseases: gonado-structural and/or gonado-activational? A meta-analysis of relevant epidemiological studies

BACKGROUND

A vast scientific literature has dealt with gender-specific risk for brain disorder. That field is evolving toward a consensus to the effect that the estrogen hormone family is outstandingly and uniquely neuroprotective. However, the epidemiology relevant to this general outlook remains piecemeal.

METHOD

The present investigation strategically formats the relevant epidemiological findings around the world in order to quantitatively meta-analyze gender ratio of risk for a variety of relevant severe central nervous system (CNS) diseases at all three gonadal stages of the life cycle, pre pubertal, post adolescent/pre menopausal, and post menopausal.

RESULTS

The data quantitatively establish that (1) no single epidemiological study should be cited as evidence of gender-specific neuroprotection against the most common severe CNS diseases because the gender-specific risk ratios are contradictory from one study to the other; (2) risk for severe CNS disease is indeed significantly gender-specific, but either gender can be protected: it depends on the disease, not at all on the age bracket.

CONCLUSION

Our assay of gender-specific risk for severe brain disease around the world has not been able to support the idea according to which any one gender-prevalent gonadal steroid hormone dominates as a neuroprotective agent at natural concentrations.

Aneurysmal subarachnoid hemorrhage: relationship to solar activity in the United States, 1988-2010

Aneurysmal subarachnoid hemorrhage (SAH) is a common condition treated by neurosurgeons. The inherent variability in the incidence and presentation of ruptured cerebral aneurysms has been investigated in association with seasonality, circadian rhythm, lunar cycle, and climate factors. We aimed to identify an association between solar activity (solar flux and sunspots) and the incidence of aneurysmal SAH, all of which appear to behave in periodic fashions over long time periods. The Nationwide Inpatient Sample (NIS) provided longitudinal, retrospective data on patients hospitalized with SAH in the United States, from 1988 to 2010, who underwent aneurysmal clipping or coiling. Solar activity and SAH incidence data were modeled with the cosinor methodology and a 10-year periodic cycle length. The NIS database contained 32,281 matching hospitalizations from 1988 to 2010. The acrophase (time point in the cycle of highest amplitude) for solar flux and for sunspots were coincident. The acrophase for aneurysmal SAH incidence was out of phase with solar activity determined by non-overlapping 95% confidence intervals (CIs). Aneurysmal SAH incidence peaks appear to be delayed behind solar activity peaks by 64 months (95% CI; 56-73 months) when using a modeled 10-year periodic cycle. Solar activity (solar flux and sunspots) appears to be associated with the incidence of aneurysmal SAH. As solar activity reaches a relative maximum, the incidence of aneurysmal SAH reaches a relative minimum. These observations may help identify future trends in aneurysmal SAH on a population basis.

Morphological and clinical risk factors for posterior communicating artery aneurysm rupture

OBJECT

Recent studies have shown that posterior circulation aneurysms, specifically posterior communicating artery (PCoA) aneurysms, are more likely to rupture than other aneurysms. To date, few studies have investigated the factors contributing to PCoA aneurysm rupture. The authors aimed to identify morphological and clinical characteristics predisposing to PCoA aneurysm rupture.

METHODS

The authors retrospectively reviewed 134 consecutive patients with PCoA aneurysms managed at their facility between July 2003 and December 2012. The authors divided patients into groups of those with aneurysmal rupture (n = 39) and without aneurysmal rupture (n = 95) and compared morphological and clinical characteristics. Morphological characteristics were mainly evaluated by 3D CT angiography and included diameter of arteries (anterior cerebral artery, middle cerebral artery, and internal carotid artery), size of the aneurysm, dome-to-neck ratio, neck direction of the aneurysmal dome around the PCoA (medial, lateral, superior, inferior, and posterior), aneurysm bleb formation, whether the PCoA was fetal type, and the existence of other intracranial unruptured aneurysm(s).

RESULTS

Patients with ruptured PCoA aneurysms were significantly younger (a higher proportion were < 60 years of age) and a significantly higher proportion of patients with ruptured PCoA aneurysms showed a lateral direction of the aneurysmal dome around the PCoA, had bleb formation, and the aneurysm was > 7 mm in diameter and/or the dome-to-neck ratio was > 2.0. Multivariate logistic regression analysis showed age < 60 years (OR 4.3, p = 0.011), history of hypertension (OR 5.1, p = 0.008), lateral direction of the aneurysmal dome around the PCoA (OR 6.7, p = 0.0001), and bleb formation (OR 11, p < 0.0001) to be significantly associated with PCoA aneurysm rupture.

CONCLUSIONS

The present results demonstrated that lateral projection of a PCoA aneurysm may be related to rupture.

Association between the daily temperature range and occurrence of spontaneous intracerebral hemorrhage

OBJECTIVE

We have observed, anecdotally, that the incidence of primary spontaneous intracerebral hemorrhage (sICH), as well as spontaneous subarachnoid hemorrhage, varies in accordance with seasonality and meteorological conditions. This retrospective single-hospital-based study aimed to determine the seasonality of sICH and the associations, if any, between the occurrence of sICH and meteorological parameters in Incheon city, which is a northwestern area of South Korea.

METHODS

Electronic hospital data on 708 consecutive patients admitted with primary sICH from January 2008 to December 2010 was reviewed. Traumatic and various secondary forms of ICHs were excluded. Average monthly admission numbers of sICH were analyzed, in relation with the local temperature, atmospheric pressure, humidity, and daily temperature range data. The relationships between the daily values of each parameter and daily admission numbers of sICH were investigated using a combination of correlation and time-series analyses.

RESULTS

No seasonal trend was observed in sICH-related admissions during the study period. Furthermore, no statistically significant correlation was detected between the daily sICH admission numbers and the meteorological parameters of temperature, atmospheric pressure and humidity. The daily temperature range tended to correlate with the number of daily sICH-related admissions (p = 0.097).

CONCLUSION

This study represents a comprehensive investigation of the association between various meteorological parameters and occurrence of spontaneous ICH. The results suggest that the daily temperature range may influence the risk of sICH.

A combination of genetic, molecular and haemodynamic risk factors contributes to the formation, enlargement and rupture of brain aneurysms

Many people carry cerebral aneurysms but are generally unaware of their presence until they rupture, resulting in high morbidity or mortality. The pathogenesis and aetiology of aneurysms are largely unknown; however, a greater understanding, by analysing the genetic, molecular and haemodynamic risk factors involved in the initiation, enlargement, and rupture of aneurysms, could lead to effective prevention, early diagnosis and more effective treatment. The risk of aneurysm is increased by a family history of aneurysms, and amongst certain populations, namely in Japan and Finland. Several other risk factors are documented, including hypertension, smoking, alcohol consumption, and female sex. Studies indicate a higher occurrence of cerebral aneurysms in females compared to males. Oestrogen protects several components within the artery wall, and inhibits some of the inflammatory molecules that could cause aneurysms. At menopause, the oestrogen level decreases and the incidence of aneurysm increases. Haemodynamic stresses have been shown to be involved in the formation, growth and rupture of aneurysms. This is often associated with hypertension, which also increases the risk of aneurysm rupture. When an unruptured aneurysm is detected the decision to treat can be complicated, since only 1-2% of aneurysms eventually rupture. Haemodynamic simulation software offers an effective tool for the consideration of treatment options for patients who carry unruptured aneurysms. The assessment must consider the risks of interventional treatments versus non-interventional management options, such as controlling blood pressure.

Incidence of growth and rupture of unruptured intracranial aneurysms followed by serial MRA

BACKGROUND

The natural history, including growth and rupture, of unruptured intracranial aneurysms (UIAs) remains unknown. Here, we present the results of serial magnetic resonance angiography (MRA) follow-up study in 111 patients with 136 UIAs.

METHOD

A total of 111 patients with 136 UIAs were followed annually over the past 12 years, using 1.5-Tesla MRA. Follow-up was ended when UIAs were treated surgically, or the patients died of subarachnoid hemorrhage or other causes. Various factors influencing aneurysm rupture or growth were examined statistically.

RESULTS

Aneurysm rupture and growth occurred in six and 13 of the 111 patients, respectively. Annual rupture rate was 1.8 % per year and annual growth rate was 3.9 % per year. Aneurysm size was the sole factor influencing rupture(H.R. 1.214, 95 % CI, 1.078-1.368) and multiplicity was the sole factor influencing aneurysm growth (H.R. 5.174, 95 % CI 1.81-14.80).

CONCLUSIONS

Serial MRA study showed that the incidence of UIA growth was twice as high as that of UIA rupture. As four patients showed aneurysm rupture or growth within 1 year, further investigations are necessary to determine the optimum interval of radiological investigation and to identify which UIAs grow or rupture within a short time.

Etiology and outcome determinants of intracerebral hemorrhage in a south Indian population, A hospital-based study

Background:

There is paucity of methodologically sound published studies on intracerebral hemorrhage (ICH) from India, on pub med/embase search.

Aims:

To explore etiology of ICH and correlate the causes, location, and size of hemorrhage to clinical outcome.

Materials and Methods:

A hospital-based descriptive study from South Indian eastern coastal town of Puducherry; 60 consecutive subjects aged > 12 years, predominantly of inbred Tamil population, with head CT evidence of intracerebral hemorrhage not associated with trauma and brain tumors, were recruited. Outcome at three months was measured using Glasgow Outcome scale, NIHSS and mortality. SPSS v 19 was used for statistical analysis.

Results:

Commonest etiological factor was hypertension, followed by bleeding diathesis, thrombolysis for myocardial infarction, and cortical vein thrombosis. Most frequent locations of hematoma were basal ganglia, thalamus, internal capsule, and cerebral and cerebellar parenchyma. Hematoma volume correlated significantly with systolic and mean arterial pressure but not with diastolic blood pressure. Poor outcome was correlated to size (P < 0.05) and intraventricular extension of hematoma (P < 0.05), and to systolic, diastolic and mean arterial pressure, but not to age, gender, smoking, alcoholism, ischemic heart disease, and blood sugar level. Among diabetic patients with ICH, the size of hematoma (P = 0.04) and severity of coma (P = 0.01) at admission were significantly worse compared to the non-diabetic, but not the outcome at three months [Glasgow outcome scale or mortality (P = 0.94 and 0.14)].

Conclusions:

The location of hemorrhage and correlation with outcome agreed with the patterns described for the non-white races in prior reports. Independence of outcome to diabetic status despite a more severe initial presentation may indicate importance of good care, even in high risk groups.

Subarachnoid hemorrhage in Kashmir: Causes, risk factors, and outcome

Context:

Kashmir, a snow bound and mountain locked valley, is populated by about 7 million ethnic and non-migratory Kashmiris who have specific dietary and social habits than rest of the world. The neurological disorders are common in Kashmiri population.

Aims:

To study the prevalence and outcome of spontaneous intracranial subarachnoid hemorrhage (SAH) in Kashmir compared withother parts of the world.

Settings and Design:

A retrospective and hospital based study from 1982 to 2010 in the single and only Neurosurgical Centre of the State of Jammu and Kashmir.

Materials and Methods:

A hospital based study, in which, information concerning all Kashmiri patients was collected from the case sheets, patient files, discharge certificates, death certificates, and telephonic conversations with the help of Medical Records Department and Central Admission Register of Sher–i-Kashmir Institute of Medical Sciences, Kashmir India.

Statistical Analysis:

Analysis of variance and students T-test were used at occasions.

Results:

Incidence of SAH in Kashmiris is about 13/100,000 persons per year. SAH comprises 31.02% of total strokes and aneurysmal ruptures are cause of 54.35% SAHs. The female suffers 1.78 times more than the male. Total mortality of 36.60% was recorded against a good recovery of 14.99%. The familial SAHs and multiple aneurysms were also common. Intra-operative finding of larger aneurysmal size than recorded on pre-operative computed tomography (CT) angiogram of same patients was noteworthy. In 493 patients of SAH, the angiography revealed 705 aneurysms.

Conclusion:

Spontaneous intracranial subarachnoid hemorrhage, due to aneurysmal rupture, is common in Kashmir, with worst outcome. Food habits like “salt-tea twice a day”, group-smoking of wet tobacco like “Jejeer”, winter season, female gender, hypertension, and inhalation of “Kangri” smoke are special risk factorsof SAH, in Kashmiris. The plain CT brain and CT angiography are best diagnostic tools. The preventive measures for aneurysmal formation and rupture seems most promising management of future. The detachable endovascular aneurysmal occupying video assisted micro-camera capsules or plugs may be future treatment.

Falling temperature and colder weather are associated with an increased risk of aneurysmal subarachnoid hemorrhage

OBJECTIVE

To use weather data to predict increased incidence of aneurysmal subarachnoid hemorrhage (aSAH) at a large institution with an extensive referral network in response to falling temperatures.

METHODS

In a retrospective study, 1175 prospectively collected aSAH cases accrued over 18 years from one hospital were reviewed to determine if season, maximum ambient temperature (MAT), average relative humidity, and atmospheric pressure were related to incidence of aSAH at that institution on a given day. A Poisson regression model was used to assess daily risk of incident aSAH based on daily MAT and 1-day change in MAT.

RESULTS

A MAT decrease of 1°F from one day to the next was associated with a 0.6% increase in risk of aSAH (relative risk [RR]=1.006, P=0.016). The increased risk associated with MAT decrease from the previous day was especially strong for female patients (RR=1.008/°F, P=0.007) and drove the overall model, representing 72% of cases. In addition, warmer temperatures were associated with a decreased risk of aSAH; each 1°F increase in temperature compared with the previous day was associated with a 0.3% decrease in risk of aSAH (RR=0.997; P<0.001).

CONCLUSIONS

A 1-day decrease in temperature and colder daily temperatures were associated with an increased risk of incident aSAH at a single institution with a large referral network. These variables appeared to act synergistically and independently of season. These relationships were particularly predominant in the fall when the transition from warmer to colder temperatures occurred.

Subarachnoid hemorrhage incidence in the United States does not vary with season or temperature

BACKGROUND AND PURPOSE

Previous studies have suggested seasonal variations in rates of spontaneous rupture of intracranial aneurysms, leading to potentially devastating SAH. In an effort to identify a seasonal effect, variation in SAH incidence and in-hospital mortality rates were examined as they relate to admission month, temperature, and climate using HCUP's Nationwide Inpatient Sample.

MATERIALS AND METHODS

Cases of nontraumatic SAH and subsequent in-hospital mortality were extracted from the 2001-2008 NIS and associated with month of occurrence, local average monthly temperatures, and USDA climate zone. Multivariate regression analysis was used to study how admission month, temperature, and climate affected SAH admission and mortality rates.

RESULTS

Among 57,663,486 hospital admissions from the 2001-2008 NIS, 52,379 cases of spontaneous SAH (ICD-9-CM 430) and 13,272 cases of subsequent in-hospital mortality were identified. SAH incidence and in-hospital mortality rates were not significantly correlated with a monthly/seasonal effect (incidence, χ(2) = 2.94, P = .99; mortality, χ(2) = 6.91, P = .81). However, SAH incidence significantly varied with climate (P < .0001, zones 11 and 7) but not with temperature (P = .1453), whereas average monthly temperature and climate had no significant correlation with in-hospital mortality (temperature, P = .3005; climate, P = .0863).

CONCLUSIONS

We identified no significant monthly or temperature-related effect in the incidence of SAH. Our data suggest that certain climate zones within the United States may be associated with significantly different SAH incidence, but the origins of these differences remain unclear and are probably unrelated to meteorologic variables.

An analysis of admissions from 155 United States hospitals to determine the influence of weather on stroke incidence

Weather is the most frequently proposed factor driving apparent seasonal trends in stroke admissions. Here, we present the largest study of the association between weather and ischemic stroke in the USA to date. We consider admissions to 155 United States hospitals in 20 states during the five-year period from 2004 to 2008. The data set included 196,439 stroke admissions, which were classified as ischemic (n=98,930), hemorrhagic (n=18,960), or transient ischemic attack (n=78,549). Variations in stroke admissions were tested to determine if they tracked seasonal and transient weather patterns over the same time period. Using autocorrelation analyses, no significant seasonal changes in stroke admissions were observed over the study period. Using time-series analyses, no significant association was observed between any weather variable and any stroke subtype over the five-year study. This study suggests that seasonal associations between weather and stroke are highly confounded, and an association between weather and stroke is virtually non-existent. Therefore, previous studies reporting an association between specific weather patterns and stroke should be interpreted with caution.

The Association Between Weather and Spontaneous Subarachnoid Hemorrhage: An Analysis of 155 US Hospitals

BACKGROUND:

A seasonal and meteorological influence on the incidence of spontaneous subarachnoid hemorrhage (SAH) has been suggested, but a consensus in the literature has yet to emerge.

OBJECTIVE:

This study examines the impact of weather patterns on the incidence of SAH using a geographically broad analysis of hospital admissions and represents the largest study of the topic to date.

METHODS:

We retrospectively analyzed SAH admissions to 155 US hospitals during the calendar years 2004 to 2008 (N = 7758). Daily weather readings for temperature, pressure, and humidity were obtained for the same period from National Oceanic and Atmospheric Administration weather stations located near each hospital. The daily values of each weather variable were associated with the daily volume of SAH admissions using a combination of correlation and time-series analyses.

RESULTS:

No seasonal trends were observed in the monthly volume of SAH admissions during the study period. No significant correlation was detected between the daily SAH admission volume and the day's weather, the previous day's weather, or the 24-hour weather change.

CONCLUSION:

This study represents the most comprehensive investigation of the association between weather and spontaneous SAH to date. The results suggest that neither season nor weather significantly influences the incidence of SAH.

Timing pattern of onset in hypertensive intracerebral hemorrhage patients

The temporal pattern of onset of hypertensive intracerebral hemorrhage (ICH) has been evaluated in previous reports, but there are few published data on this pattern in Chongqing, China. The purpose of this study is to explore the temporal pattern of diurnal, weekly and monthly variations in the onset of hypertensive ICH from a hospital-based population. The study retrospectively reviewed 230 residents who suffered from hypertensive ICH between January 2008 and August 2009 in our hospital. The temporal pattern was investigated by hours, days and months. Chi-square test for goodness of fit was used for statistical analysis. Significant differences of the onset time of hypertensive ICH patients could be seen in diurnal variation (p=0.000) and in monthly variation (p=0.000), but could not be found in weekly variation (p=0.466). There was a bimodal distribution in diurnal variation, and monthly variation showed that the occurrence of hypertensive ICH mainly focuses on the period from December to May. Our study demonstrated the existence of diurnal and monthly variations and no significant weekly variation can be found in the time of onset of hypertensive ICH.

Epidemiology of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a form of hemorrhagic stroke that affects up to 30,000 individuals per year in the United States. The incidence of aSAH has been shown to be associated with numerous nonmodifiable (age, gender, ethnicity, family history, aneurysm location, size) and modifiable (hypertension, body mass index, tobacco and illicit drug use) risk factors. Although early repair of ruptured aneurysms and aggressive postoperative management has improved overall outcomes, it remains a devastating disease, with mortality approaching 50% and less than 60% of survivors returning to functional independence. As treatment modalities change and the percentage of minority and elderly populations increase, it is critical to maintain an up-to-date understanding of the epidemiology of SAH.

Incidence rate of Aneurysmal SAH in Gwangju City and Jeollanamdo Province in 2007

OBJECTIVE

The incidence of subarachnoid hemorrhage (SAH) worldwide varies considerably. In spite of many reports about the incidence of SAH, there has been no report about the incidence of SAH on the basis of the Korean population. The purpose of this hospital-based study was to assess the actual incidence rates of aneurysmal SAH in Gwangju city and Jeollanamdo province.

METHODS

All cases of SAH confirmed by computerized tomography (CT) between January 2007 and December 2007 were selected for analysis. For the data collection, three major training hospital and ten general hospitals working the CT in Gwangju city and four major general hospitals in Jeollanamdo province participate in this study.

RESULTS

According to the official census of Korea, the population was 1,413,444 in Gwangju city and 1,929,836 in Jeollanamdo province in 2007. There were 163 patients in Gwangju city and 266 patients in Jeollanamdo province confirmed SAH by CT in 2007. The crude and the age- and sex-adjusted annual incidence rates per 100,000 population for all ages in Gwangju city were 11.5 and 12.4 for aneurysmal SAH and in Jeollanamdo province were 13.8 and 10.8. The incidence was higher in women and increased with age. The gender distribution varied with age. At young ages, the incidence was higher in men while after the age of 40 years, the incidence was higher in women.

CONCLUSION

In the present study, the age- and sex-adjusted annual incidence rates is 11.8 in Gwangju city and Jeollanamdo province. The incidence was higher in women and increased with age.

Risk factors for the formation and rupture of intracranial saccular aneurysms in Shimane, Japan

BACKGROUND

Prevention of aneurysmal subarachnoid hemorrhage (SAH) can be achieved by reducing risk factors, which include those for aneurysm formation and aneurysm rupture. However, neither of these 2 factors has been discussed separately so far. A case control study was undertaken in Shimane, Japan, to identify modifiable risk factors for the formation and rupture of aneurysms.

METHODS

This study included 858 patients with ruptured aneurysms, 285 patients with unruptured aneurysms without a history of SAH, and 798 control subjects. Hypertension, diabetes mellitus, heart disease, hypercholesterolemia, cigarette smoking, and alcohol consumption were assessed as risk factors by using conditional logistic regression.

RESULTS

After adjustment for other risk factors, hypertension was the most powerful risk factor for aneurysm formation, regardless of age and sex, followed by hypercholesterolemia, heart disease, and cigarette smoking, whereas diabetes mellitus and daily drinking were insignificant for aneurysm formation. Hypertension and daily drinking were not related to the risk of aneurysm rupture, regardless of age and sex, whereas cigarette smoking was associated with an increased risk of aneurysm rupture in patients 60 years or older and in men. In contrast, hypercholesterolemia was strongly associated with a decreased risk of rupture, regardless of age and sex, and in patients with small aneurysms (<5 mm). Diabetes mellitus and heart disease were also related to a decreased risk of rupture in patients 60 years or older and in women.

CONCLUSION

Identification of risk factors for aneurysm formation and rupture separately seems to be pivotal for reducing the incidence of SAH.

Dependence of subarachnoid hemorrhage on climate conditions: a systematic meteorological analysis from the dusseldorf metropolitan area

OBJECTIVE

A number of publications suggest that there are seasonal influences on the incidence of subarachnoid hemorrhage (SAH). Most series agree on a peak incidence during springtime. Meteorological influences have been assumed to be obvious explanations for seasonal variations. Furthermore, the perceived clustering of the incidence of subarachnoid hemorrhage is also intuitively related to meteorological influences. The present study was initiated to determine whether specific meteorological conditions are related to the occurrence of SAH in the mild climatic zone of North Rhine Westphalia.

METHODS

We retrospectively examined 183 patients (107 women and 76 men) treated at our department between January 2003 and June 2005 for SAH that had occurred within the Düsseldorf metropolitan area. We correlated the date of SAH (Day 0) and of the week preceding the incident (Days -1, -3, -5, and -7) with the meteorological key parameters from Düsseldorf International Airport. Parameters analyzed were mean daily temperature (7C), relative humidity (%), barometric pressure (hPa), and weather condition (divided into 6 groups: clear, cloudy, rain, thunderstorms, snow, and not available).

RESULTS

A relative peak incidence of SAH was found for the month of April. In addition, a diurnal rhythm with two peaks during morning and in the evening, and a statistically significant nadir during forenoon and midday was evident (P <0.002). None of the average meteorological key parameters of the day of SAH differed from the annual average, and no general trends during the days preceding hemorrhage could be identified. Apparent clustering of the occurrence of SAH could not be related to short-term meteorological trends.

CONCLUSION

The results of the present study demonstrate a trend toward a seasonal distribution in the incidence of SAH with a peak during spring in the metropolitan area of Düsseldorf. Furthermore, weather variables, such as temperature, barometric pressure, and humidity, were shown to be without influence on aneurysm rupture within the patient population. Therefore, the result indicates the need to validate further parameters in detail to isolate risk circumstances to achieve a risk pattern for patients with SAH.

Involvement of meteorological factors and sex in the occurrence of subarachnoid hemorrhage in Japan

The sex difference in the seasonal occurrence of subarachnoid hemorrhage (SAH) and the association of meteorological factors in Japan were analyzed in 1006 consecutive patients with SAH in Toyama, Japan from 1996 to 2000. The study investigated whether these meteorological factors could explain the seasonality of the incidence of SAH in each sex. Seasonal variation of SAH occurrence peaked in spring in men, but peaked in spring and winter in women. The difference between maximum temperature and minimum temperature was the greatest on the day previous to SAH occurrence in multiple individuals in men, whereas mean humidity was the greatest on that day in women. Interestingly, the difference between maximum temperature and minimum temperature peaked in spring and mean humidity in winter from the meteorological data over the 5 years. The relationship between humidity and occurrence of SAH may explain the sex difference of the incidence of aneurysmal SAH. The humidity change may be a specific and additional meteorological factor for the incidence of SAH in women.

Prediction of the incidence of spontaneous intracerebral hemorrhage from meteorological data

We analyzed the relationship between the incidence of spontaneous intracerebral hemorrhage (ICH) and various meteorological data (daily atmospheric air pressure, air temperature, precipitation, humidity, presence of typhoons, occurrence of the rainy season, wind velocity, and wind direction) for patients at Teraoka Memorial Hospital in Shin-ichi Town, Japan, from January 1, 2001 to December 31, 2003. All data were analyzed by contingency table analysis and multivariate regression analysis. From January 1, 2002 to December 31, 2003, we identified high-risk ICH days as those days for which the preceding 3 days mean recorded air pressure of 1,015 hPa or more and then conducted a statistical comparison of the incidence of ICH on high-risk ICH days with that on the other days. Our subjects were 164 patients with ICH. The relative risk of high-risk ICH days is 1.46 (Fisher's exact test, p=0.04). Mann-Whitney's U-tests indicate ICH tends to occur on days with lower maximum air temperature. Multivariate logistic regression analysis revealed that 3 incidences influence the occurrence of intracerebral hemorrhage (p<0.01 each): (1) days associated with 4-day periods of mean air pressure in excess of 1,015 hPa; (2) days during which a typhoon was approaching; and (3) days with west or southwest wind . Detailed examination of meteorological data indicates a relationship with the incident rate of ICH.

Incidence of subarachnoid haemorrhage: a systematic review with emphasis on region, age, gender and time trends

BACKGROUND AND AIM

To update our 1996 review on the incidence of subarachnoid haemorrhage (SAH) and assess the relation of incidence with region, age, gender and time period.

METHODS

We searched for studies on the incidence of SAH published until October 2005. The overall incidences with corresponding 95% confidence intervals were calculated. We determined the relationship between the incidence of SAH and determinants by means of univariate Poisson regression.

RESULTS

We included 51 studies (33 new), describing 58 study populations in 21 countries, observing 45,821,896 person-years. Incidences per 100,000 person-years were 22.7 (95% CI 21.9 to 23.5) in Japan, 19.7 (18.1 to 21.3) in Finland, 4.2 (3.1 to 5.7) in South and Central America, and 9.1 (8.8 to 9.5) in the other regions. With age category 45-55 years as the reference, incidence ratios increased from 0.10 (0.08 to 0.14) for age groups younger than 25 years to 1.61 (1.24 to 2.07) for age groups older than 85 years. The incidence in women was 1.24 (1.09 to 1.42) times higher than in men; this gender difference started at age 55 years and increased thereafter. Between 1950 and 2005, the incidence decreased by 0.6% (1.3% decrease to 0.1% increase) per year.

CONCLUSIONS

The overall incidence of SAH is approximately 9 per 100,000 person-years. Rates are higher in Japan and Finland and increase with age. The preponderance of women starts only in the sixth decade. The decline in incidence of SAH over the past 45 years is relatively moderate compared with that for stroke in general.

Risk factors for primary intracerebral hemorrhage in patients in Izumo City, Japan

The annual incidence rate of primary intracerebral hemorrhage (ICH) in Izumo City, Japan, appears to be the highest rate among those reported. Despite improvement of management and surgical therapy, the overall morbidity and mortality after ICH are still high. The author investigated the risk factors for ICH in patients in Izumo. A case-control study of 242 patients (137 men and 105 women with ages ranging from 34 to 97 years) with primary ICH was conducted in Izumo between 1991 and 1998. Hypertension, diabetes mellitus, heart disease, liver disease, alcohol consumption, cigarette smoking, and serum levels of total cholesterol, aspartate aminotransferase, and alanine aminotransferase were assessed as possible risk factors for ICH by using conditional logistic regression. The prevalence of hypertension among ICH patients was 77% and the odds ratio (OR) for hypertension was 17.07 (95% CI: 8.30-35.09), which are much higher than figures reported from Western countries. The OR for hypertension was higher in individuals < or = 69 years of age than in those > or = 70 years of age and lower for lobar hemorrhage than for hemorrhages at other sites. High serum total cholesterol (> or = 220 mg/dl) was the second most important risk factor for ICH (OR: 2.52; 95% CI: 1.23-5.14), and low total cholesterol (< 160 mg/dl) decreased the risk of ICH (OR: 0.47; 95% CI: 0.27-0.82). In contrast, heart disease decreased the risk of ICH, and there was no observed association between alcohol consumption, cigarette smoking, or diabetes mellitus and ICH. This study conducted in Izumo suggests that hypertension is the most important risk factor for ICH and contrary to most previous studies indicates that serum total cholesterol concentration is also positively associated with the risk of ICH. In contrast, heart disease may decrease the risk of ICH.

Differences in circadian variation of cerebral infarction, intracerebral haemorrhage and subarachnoid haemorrhage by situation at onset

BACKGROUND

The precise time of stroke onset during sleep is difficult to specify, but this has a considerable influence on circadian variations of stroke onset.

AIM

To investigate circadian variations in situations at stroke onset--that is, in the waking state or during sleep--and their differences among subtypes.

METHODS

12,957 cases of first-ever stroke onset diagnosed from the Iwate Stroke Registry between 1991 and 1996 by computed tomography or magnetic resonance imaging were analysed. Circadian variations were compared using onset number in 2-h periods with relative risk for the expected number of the average of 12 2-h intervals in the waking state or during sleep in cerebral infarction (CIF), intracerebral haemorrhage (ICH) and subarachnoid haemorrhage (SAH).

RESULTS

ICH and SAH showed bimodal circadian variations and CIF had a single peak in all situations at onset, whereas all three subtypes showed bimodal circadian variations of stroke onset in the waking state only. These variations were different in that CIF showed a bimodal pattern with a higher peak in the morning and a lower peak in the afternoon, whereas ICH and SAH had the same bimodal pattern with lower and higher peaks in the morning and afternoon, respectively.

CONCLUSIONS

Sleep or status in sleep tends to promote ischaemic stroke and suppress haemorrhagic stroke. Some triggers or factors that promote ischaemic stroke and prevent haemorrhagic stroke in the morning cause different variations in the waking state between ischaemic and haemorrhagic stroke.

Recurrent primary intracerebral hemorrhage in Izumo City, Japan

BACKGROUND

Recurrent intracerebral hemorrhage (ICH) is a devastating illness among stroke survivors. We investigated the rate and characteristics of ICH recurrence in Izumo City, Japan.

METHODS

The recurrence rate of ICH was calculated for 279 patients who suffered their first-ever ICH between 1991 and 1998 and were followed up during a mean period of 3.0 years (range, 1 month to 11 years). The characteristics of recurrent ICH were evaluated for 42 patients who were treated for it between 1991 and 1998.

RESULTS

Of the 279 patients with ICH, 19 (7%) had rebleeding; the recurrence rate was 2.3% per year. Analysis of the 42 patients with recurrent ICH showed that the most common pattern of recurrence was ganglionic-ganglionic (n = 25). The crude and the age- and sex-adjusted annual incidence rates for recurrent ICH were both 6 per 100,000 population. Of the 42 patients with recurrent ICH, 16 (38%) had a favorable outcome at discharge and 10 (24%) died. The overall 1-year survival rate for recurrent ICH was 72%. Intraventricular hemorrhage on computed tomography scans was the only significant predictor of not only ICH recurrence but also the 1-year case-fatality rate in patients with recurrent ICH.

CONCLUSIONS

Recurrence after an initial ICH is not rare, and the most common pattern of recurrence is ganglionic-ganglionic. Whereas the functional outcome of recurrent ICH is unsatisfactory, the 1-year survival rate is not necessarily low. Intraventricular hemorrhage on computed tomography scans is an important predictor of both ICH recurrence and the 1-year case-fatality rate in patients with recurrent ICH.

Risk factors for aneurysmal subarachnoid hemorrhage in patients in Izumo City, Japan

OBJECT

The annual incidence of aneurysmal subarachnoid hemorrhage (SAH) in Izumo City, Japan, appears to be the highest rate among those reported; therefore the author investigated the risk factors for SAH in patients in this city.

METHODS

A case-control study of 247 patients (108 men and 139 women with ages ranging from 28-96 years) with aneurysmal SAH was conducted in Izumo between 1980 and 1998. Hypertension, diabetes mellitus, heart disease, liver disease, cigarette smoking, alcohol consumption, and serum levels of total cholesterol, aspartate aminotransferase, alanine aminotransferase, and urea nitrogen were assessed as possible risk factors for SAH by using conditional logistic regression. After adjustment for other risk factors, results of multivariate analysis showed that hypertension was the most powerful risk factor, regardless of age and sex. The odds ratio for hypertension was higher in women than in men. The second greatest risk factors were cigarette smoking in those 59 years of age or younger and in men and hypercholesterolemia in those 60 years of age or older and in women. Among individuals 60 years of age or older and among women, diabetes mellitus and heart disease were inversely associated with the risk of SAH. When analyses were performed in 219 cases of confirmed ruptured cerebral aneurysm, very similar results were obtained.

CONCLUSIONS

Among patients in Izumo, hypertension was the most notable risk factor for aneurysmal SAH, regardlessof age and sex, followed by cigarette smoking in younger men and hypercholesterolemia in older women. In older women, diabetes mellitus and heart disease decreased the risk of SAH.

Trends in Surgical and Management Outcomes in Patients with Aneurysmal Subarachnoid Hemorrhage in Izumo City, Japan, between 1980–1989 and 1990–1998

BACKGROUND AND PURPOSE

The purpose of this community-based study was to evaluate temporal changes in surgical and management outcomes in patients with aneurysmal subarachnoid hemorrhage (SAH).

METHODS

The subjects were 358 patients with aneurysmal SAH who were treated during the 19-year period from 1980 to 1998 in Izumo City, Japan. We compared data during the 9-year period 1990-1998 (period B; 188 patients) with those during the 10-year period 1980-1989 (period A; 170 patients).

RESULTS

The proportion of patients 80 years of age or older or those with World Federation of Neurosurgical Societies grade V increased significantly (period A, 5 and 25%; period B, 18 and 35%, respectively). The operability rate did not change for patients 69 years of age or younger, whereas it increased significantly for those 70-79 years of age (period A, 48%; period B, 72%). The 6-month and 2-year case fatality rates in surgically treated patients decreased significantly (period A, 12 and 20%; period B, 2 and 8%, respectively), whereas they were virtually unchanged for overall management (period A, 41 and 46%; period B, 38 and 42%, respectively). In patients who underwent surgery, the incidence of permanent symptomatic vasospasm decreased from 21% during period A to 11% during period B, and there was no death from vasospasm in the later period. However, no significant difference was found in the functional outcome between the two periods, regardless of whether surgery was performed. The most important determinants of 6-month and 2-year survival rates were grade on admission, rebleeding and the site of the ruptured aneurysms. Age was also a significant predictor of the 6-month case fatality rate.

CONCLUSIONS

For patients with SAH who underwent surgery, there were trends towards decreases in the case fatality rate and in the incidence of permanent symptomatic vasospasm. Nevertheless, the overall management outcome was still unsatisfactory, mainly because of increasing numbers of very elderly and/or high-risk patients. .