Calcium antagonists for aneurysmal subarachnoid haemorrhage

BACKGROUND

Secondary ischaemia is a frequent cause of poor outcome in patients with subarachnoid haemorrhage (SAH). Its pathogenesis has not been elucidated yet, but may be related to vasospasm. Experimental studies have indicated that calcium antagonists can prevent or reverse vasospasm and have neuroprotective properties. Several types of calcium antagonists have been studied in several clinical trials.

OBJECTIVES

To determine whether calcium antagonists improve outcome in patients with aneurysmal SAH.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (September 2003). In addition, we searched MEDLINE (1966 to October 2003) and EMBASE (1980 to October 2003), handsearched two Russian journals (1990 to 2003) and contacted trialists and pharmaceutical companies (in 1995 and 1996) to identify further studies.

SELECTION CRITERIA

All unconfounded, truly randomised controlled trials comparing any calcium antagonist with control.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted the data and assessed trial quality. Trialists were contacted to obtain missing information.

MAIN RESULTS

We analysed 12 trials totalling 2844 patients with SAH (1396 in the treatment group and 1448 in the control group). The drugs analysed were: nimodipine (eight trials, 1574 patients), nicardipine (two trials, 954 patients), AT877 (one trial, 276 patients) and magnesium (one trial, 40 patients). Overall, calcium antagonists reduced the risk of poor outcome: relative risk (RR) 0.82 (95% confidence interval (CI) 0.72 to 0.93); the absolute risk reduction was 5.1%, the corresponding number of patients needed to treat to prevent a single poor outcome event was 20. For oral nimodipine alone the RR was 0.70 (0.58 to 0.84). The RR of death on treatment with calcium antagonists was 0.90 (95% CI 0.76 to 1.07), that of clinical signs of secondary ischaemia 0.67 (95% CI 0.60 to 0.76), and that of CT or MR confirmed infarction 0.80 (95% CI 0.71 to 0.89).

AUTHORS' CONCLUSIONS

Calcium antagonists reduce the risk of poor outcome and secondary ischaemia after aneurysmal SAH. The results for 'poor outcome' depend largely on a single large trial with oral nimodipine; the evidence for nicardipine, AT877 and magnesium is inconclusive. The evidence for nimodipine is not beyond every doubt, but given the potential benefits and modest risks of this treatment, against the background of a devastating natural history, oral nimodipine (60 mg every 4 hours) is currently indicated in patients with aneurysmal SAH. Intravenous administration of calcium antagonists cannot be recommended for routine practice on the basis of the present evidence.

Circulatory volume expansion therapy for aneurysmal subarachnoid haemorrhage

BACKGROUND

Secondary ischaemia is a frequent complication after aneurysmal subarachnoid haemorrhage (SAH), and responsible for a substantial proportion of patients with poor outcome after SAH. The cause of secondary ischaemia is unknown, but hypovolaemia and fluid restriction are important risk factors. Therefore, volume expansion therapy (hypervolaemia) is frequently used in patients with SAH to prevent or treat secondary ischaemia.

OBJECTIVES

To determine the effectiveness of volume expansion therapy for improving outcome in patients with aneurysmal SAH.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched September 2003). In addition we searched MEDLINE (1966 to January 2004) and EMBASE (1980 to January 2004) and contacted trialists to identify further published and unpublished studies.

SELECTION CRITERIA

All randomised controlled trials of volume expansion therapy in patients with aneurysmal SAH. We also sought controlled trials based on consecutive groups of patients quasi-randomly allocated to treatment or control group and included these in the analysis if the two groups were well comparable with regard to major prognostic factors.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted the data and assessed trial quality. Trialists were contacted to obtain missing information.

MAIN RESULTS

We identified three trials. One truly randomised trial and one quasi-randomised trial with comparable baseline characteristics for both groups were included in the analyses. Volume expansion therapy did not improve outcome (Relative Risk (RR) 1.0; 95% Confidence Interval (CI) 0.5 to 2.2), nor the occurrence of secondary ischaemia (RR 1.1; 95% CI 0.5 to 2.2). Hypervolaemia tended to increase the rate of complications (RR 1.8; 95% CI 0.9 to 3.7) In another quasi-randomised trial, outcome assessment was done only at the day of operation (7 to 10 days after SAH). In the period before operation, treatment resulted in a reduction of secondary ischaemia (RR 0.33; 95% CI 0.11 to 0.99) and case fatality (RR 0.20; 95% CI 0.07 to 1.2).

REVIEWERS' CONCLUSIONS

The effects of volume expansion therapy have been studied properly in only two trials of patients with aneurysmal SAH, with very small numbers. At present, there is no sound evidence for the use of volume expansion therapy in patients with aneurysmal SAH.

Blood Pressure and Stroke

Background— The last few years have seen a considerable increase in the amount of information available concerning blood pressure (BP) and stroke associations. This article provides an overview of published reviews of the effects on stroke seen in trials of BP-lowering drugs and compares these with the results available from cohort studies.

Summary of Review— We present a review of major overviews of prospective cohort studies and an updated meta-analysis of >40 randomized controlled trials of BP lowering, which included >188 000 participants and approximately 6800 stroke events. Cohort studies now indicate that in the Asia Pacific region as well as in North America and Western Europe, each 10 mm Hg lower systolic BP is associated with a decrease in risk of stroke of approximately one third in subjects aged 60 to 79 years. The association is continuous down to levels of at least 115/75 mm Hg and is consistent across sexes, regions, and stroke subtypes and for fatal and nonfatal events. The proportional association is age dependent but is still strong and positive in those aged 80 years. Data from randomized controlled trials, in which mean age at event was approximately 70 years, indicate that a 10 mm Hg reduction in systolic BP is associated with a reduction in risk of stroke of approximately one third. Per mm Hg systolic BP reduction, the relative benefits for stroke appear similar between agents, by baseline BP levels, and whether or not individuals have a past history of cardiovascular disease. There is, however, evidence of greater benefit with a larger BP reduction.

Conclusions— The epidemiologically expected benefits of BP lowering for stroke risk reduction are broadly consistent across a range of different population subgroups. There are greater benefits from larger BP reductions, and initiating and maintaining BP reduction for stroke prevention is a more important issue than choice of initial agent.

Blood pressure and stroke: an overview of published reviews

BACKGROUND

The last few years have seen a considerable increase in the amount of information available concerning blood pressure (BP) and stroke associations. This article provides an overview of published reviews of the effects on stroke seen in trials of BP-lowering drugs and compares these with the results available from cohort studies.

SUMMARY OF REVIEW

We present a review of major overviews of prospective cohort studies and an updated meta-analysis of >40 randomized controlled trials of BP lowering, which included >188 000 participants and approximately 6800 stroke events. Cohort studies now indicate that in the Asia Pacific region as well as in North America and Western Europe, each 10 mm Hg lower systolic BP is associated with a decrease in risk of stroke of approximately one third in subjects aged 60 to 79 years. The association is continuous down to levels of at least 115/75 mm Hg and is consistent across sexes, regions, and stroke subtypes and for fatal and nonfatal events. The proportional association is age dependent but is still strong and positive in those aged 80 years. Data from randomized controlled trials, in which mean age at event was approximately 70 years, indicate that a 10 mm Hg reduction in systolic BP is associated with a reduction in risk of stroke of approximately one third. Per mm Hg systolic BP reduction, the relative benefits for stroke appear similar between agents, by baseline BP levels, and whether or not individuals have a past history of cardiovascular disease. There is, however, evidence of greater benefit with a larger BP reduction.

CONCLUSIONS

The epidemiologically expected benefits of BP lowering for stroke risk reduction are broadly consistent across a range of different population subgroups. There are greater benefits from larger BP reductions, and initiating and maintaining BP reduction for stroke prevention is a more important issue than choice of initial agent.

Blood pressure and stroke: an overview of published reviews

BACKGROUND

The last few years have seen a considerable increase in the amount of information available concerning blood pressure (BP) and stroke associations. This article provides an overview of published reviews of the effects on stroke seen in trials of BP-lowering drugs and compares these with the results available from cohort studies.

SUMMARY OF REVIEW

We present a review of major overviews of prospective cohort studies and an updated meta-analysis of >40 randomized controlled trials of BP lowering, which included >188 000 participants and approximately 6800 stroke events. Cohort studies now indicate that in the Asia Pacific region as well as in North America and Western Europe, each 10 mm Hg lower systolic BP is associated with a decrease in risk of approximately one third in subjects aged 60 to 79 years. The association is continuous down to levels of at least 115/75 mm Hg and is consistent across sexes, regions, and stroke subtypes and for fatal and nonfatal events. The proportional association is age dependent but is still a strong and positive association in those aged 80 years. Data from randomized controlled trials, in which mean age at event was approximately 70 years, indicate that a 10 mm Hg reduction in systolic BP is associated with a reduction in risk of stroke of approximately one third. Per mm Hg systolic BP reduction, the benefits for stroke appear similar between agents, by baseline BP levels, and whether or not individuals have a past history of cardiovascular disease. There is, however, evidence of greater benefit with a larger BP reduction.

CONCLUSIONS

The epidemiologically expected benefits of BP lowering for stroke risk reduction are broadly consistent across a range of different population subgroups. There are greater benefits from larger BP reductions, and initiating and maintaining BP reduction for stroke prevention is a more important issue than choice of initial agent.

Systemic inflammation, endothelial dysfunction, dietary fatty acids and micronutrients as risk factors for stroke: a selective review

As medicine moves into the 21st century, with added pressures of increasing costs and limited resources, successful reduction of the impact of stroke on the population will require shifting our emphasis away from treating end stages of generalized atherosclerosis and other underlying diseases to prevention of these diseases. However, before any potential interventions can be promoted with confidence, more needs to be known about the specific causes of stroke subtypes in various populations, especially potentially modifiable risk factors. In this selective review, we appraise current evidence on some markers of systemic inflammation (C-reactive protein), endothelial dysfunction (homocysteine, von Willebrand factor), dietary fatty acids and micronutrients as risk factors for stroke. Although a great deal of research into the role of these risk factors in cardiovascular diseases has been undertaken, little reliable information is available on their role in stroke, especially in the elderly. Evaluation of plasma fatty acids and specific antioxidants and micronutrients as well as markers of systemic inflammation, endothelial dysfunction (including C-reactive protein, homocysteine levels, von Willebrand factor, and paraoxonase activity) may prove to be valuable in the future determination of the risk of stroke.

Subarachnoid haemorrhage occurrence exhibits a temporal pattern - evidence from meta-analysis

The aim of the present meta-analysis was to determine a temporal pattern of occurrence of subarachnoid haemorrhage (SAH). A MEDLINE 1966-2001 and EMBASE (1980-2001) literature search and hand search of relevant references were performed for population-based incidence studies that reported the time of SAH occurrence. Data from all identified relevant studies were combined into a pooled rate ratio (RR), with corresponding 95% confidence intervals (CI) using the Mantel-Haenszel method. Overall, eight population-based studies were included in the analysis. A total of 2533 first-ever cases of SAH were reported in the studies identified. Risk of SAH occurrence was the highest in the period between 6 am and 12 am (RR = 3.19; 95% CI 3.03-3.36; early morning as a reference variable) and between 12 p.m. and 6 p.m. (RR = 2.63; 95% CI 2.47-2.80), in winter and spring (RR = 1.10; 95% CI: 1.02-1.17; and RR = 1.07; 95% CI: 1.01-1.13, respectively; summer as a reference variable) and on Sunday (RR = 1.22; 95% CI 1.09-1.37; Monday as a reference variable). The evidence suggests that occurrence of SAH exhibits a seasonal (winter and spring) peak, diurnal (late morning peak) and daily (Sunday peak) pattern. It is suggested that the occurrence of some major acute vascular events (total ischaemic strokes, intracerebral haemorrhage and myocardial infarction) may be influenced by common triggering factors.

The emerging role of induced hypothermia in the management of acute stroke

Current treatment of acute stroke remains unsatisfactory. This review presents experimental and clinical data which suggest that mild induced hypothermia could be a potent and practicable neuroprotective treatment of acute ischaemic stroke and intracerebral haemorrhage. Hypothermia, if proven to be safe, effective and widely practicable in patients with acute stroke, could have an enormous positive impact on reducing the burden of stroke worldwide. Critical issues that will need to be considered in a well designed randomised controlled trial of induced hypothermia in acute stroke patients are discussed.

Is there a temporal pattern in the occurrence of subarachnoid hemorrhage in the southern hemisphere? Pooled data from 3 large, population-based incidence studies in Australasia, 1981 to 1997

BACKGROUND AND PURPOSE

Publications on the temporal pattern of the occurrence of subarachnoid hemorrhage (SAH) have produced conflicting results. Variations between studies may relate to the relatively small numbers of SAH cases analyzed, including those in meta-analyses.

METHODS

We identified all cases of SAH from 3 well-designed population-based studies in Australia (Adelaide, Hobart, and Perth) and New Zealand (Auckland) during 3 periods between 1981 and 1997. The diagnosis of SAH was confirmed with CT, cerebral angiography, cerebrospinal fluid analysis, or autopsy in all cases. Information on the time of occurrence of each event was obtained. Risk ratios (RRs) and 95% CIs were calculated using Poisson regression, with age, sex, smoking status, and history of hypertension entered in the model as covariates.

RESULTS

A total of 783 cases of SAH were registered. Age- and sex-adjusted RRs of SAH occurrence were highest in the period between 6 AM and 12 MIDNIGHT (RR 3.2, 95% CI 2.4-4.3) and in winter and spring (RR 1.3, 95% CI 1.1-1.5; RR 1.3, 95% CI 1.1-1.5; respectively). No particular pattern of SAH occurrence was observed according to the day of the week. Restriction of the analyses to proved aneurysmal SAH did not substantially change the point estimates.

CONCLUSIONS

Circadian and circaseptan (weekly) fluctuations of SAH occurrence in the southern hemisphere are similar to those in the northern hemisphere, but the occurrence of SAH in Australasia exhibits clear seasonal (winter and spring) peaks.

Vinpocetine treatment in acute ischaemic stroke: a pilot single-blind randomized clinical trial

The aim of the study was to assess the safety and feasibility of a clinical trial on the effect of vinpocetine, a synthetic ethyl ester of apovincamine, in acute ischaemic stroke. Thirty consecutive patients with computed tomography verified diagnosis of acute ischaemic stroke, who could receive drug treatment within 72 h of stroke onset, were enrolled. The patients were randomly allocated to receive either low-molecular weight dextran alone or in combination with vinpocetine. Poor outcome was defined as being dead or having a Barthel index of < 70 or a Rankin score of 3--5. Intention-to-treat analysis was applied. One-tenth of all hospitalized patients with acute ischaemic stroke were eligible for the trial. Thirty eligible patients were treated with either low-molecular weight dextran alone (mean age 57.9 +/- 11.6 years, n = 15) or in combination with vinpocetine (mean age 60.8 +/- 6.6 years, n = 15). The two treatment groups were comparable with respect to major prognostic variables. A relative risk (RR) reduction of poor outcome at 3 months follow-up was 30% (RR = 0.7; 95% confidence interval [CI] 0.1--3.4), as defined by the modified Barthel Index, and 60% as defined by the modified Ranking score (RR = 0.4, 95% CI: 0.1--1.7). The National Institute of Health (NIH--NINDS) Stroke Scale score was marginally significantly better in the vinpocetine treated group at 3 months of follow-up (P = 0.05, ANOVA). No significant adverse effects were seen. This pilot study shows that a full-scale randomized double-blind, placebo-controlled trial of vinpocetine treatment in acute ischaemic stroke is feasible and warranted.

A population-based study of the associations of stroke occurrence with weather parameters in Siberia, Russia (1982-92)

Previous studies have established a seasonal variation in stroke occurrence, but none have assessed the influence of inclement weather conditions on stroke incidence in a general population of Russia. We performed a stroke population-based study in the Oktiabrsky District of Novosibirsk, Siberia, Russia. Included in the analysis were 1929 patients with their first occurrence of ischemic stroke (IS), 215 patients with their first occurrence of intracerebral hemorrhage (ICH) and 64 patients with their first occurrence of subarachnoid hemorrhage (SAH): all patients were aged between 25 and 74 years. The cumulative daily occurrence of total strokes and stroke subtypes was evaluated in relation to aggregated daily mean values of ambient temperature, relative humidity and air pressure by means of Poisson regression analysis to estimate the rate ratio (RR) with corresponding confidence interval (CI) and to identify the weather parameters of most importance. In a multivariate analysis, with adjustment for the effects of season, solar and geomagnetic activity, and age of the patients, low ambient temperature (RR 1.32; 95% CI 1.05-1.66) and mean value of air pressure (RR 0.986; 95% CI 0.972-0.999) were important predictors of IS occurrence, while mild ambient temperature (RR 1.52; 95% CI 1. 04-2.22) was an important predictor of ICH occurrence. No relationship between SAH occurrence and any one of the weather parameters studied was revealed. There was no interaction between any meteorological variables that was statistically significant. Inclement weather conditions are associated with the occurrence of IS and ICH in Siberia, Russia. Among the meteorological parameters studied, low ambient temperature and mean air pressure are the most important predictors of IS occurrence, whereas the occurrence of ICH is associated with mild ambient temperature. There is no association between any one of the weather parameters studied and the occurrence of SAH.

Circulatory volume expansion for aneurysmal subarachnoid hemorrhage

BACKGROUND

Patients with subarachnoid haemorrhage who develop spasm of the cerebral arteries may suffer from delayed cerebral ischaemia. This may be exacerbated by reduced circulatory volume. Intravenous fluid therapy to expand the circulating volume might reduce the risk of delayed cerebral ischaemia and so reduce the risk of neurological disability.

OBJECTIVES

The object of this review was to determine whether there is evidence that volume expansion therapy improves outcome in patients with aneurysmal subarachnoid haemorrhage.

SEARCH STRATEGY

The Cochrane Stroke Group's Specialised Register was searched for trials relevant to this review (last searched: March 1999). Trialists were also contacted.

SELECTION CRITERIA

All randomized controlled trials of volume expansion therapy in patients with aneurysmal subarachnoid haemorrhage.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted the data and assessed trial quality. Trialists were contacted to obtain missing information.

MAIN RESULTS

Two trials were identified. For one trial the decision about inclusion is pending because clinical data on follow up have not been provided yet. In the other trial, outcome assessment was done at the day of operation (7 to 10 days after subarachnoid haemorrhage); data on longer follow up have not been collected.

REVIEWER'S CONCLUSIONS

The effects of volume expansion therapy have not been studied properly in patients with aneurysmal subarachnoid haemorrhage. At present, there is no sound evidence for or against the use of volume expansion therapy in patients with aneurysmal subarachnoid haemorrhage.

Calcium antagonists for aneurysmal subarachnoid haemorrhage

BACKGROUND

Rupture of an intracranial aneurysm causes bleeding into the subarachnoid space, which may lead to spasm of the cerebral arteries and ischaemic damage to the brain. Prophylactic use of calcium antagonists in patients with ruptured intracranial aneurysms might reduce the risk of ischaemic damage.

OBJECTIVES

This review aimed to determine whether calcium antagonists improve outcome in patients with aneurysmal subarachnoid haemorrhage (SAH).

SEARCH STRATEGY

The Cochrane Stroke Group trials register (last searched: March 1999) plus hand searching and personal contacts with trialists and pharmaceutical companies marketing calcium antagonists.

SELECTION CRITERIA

All completed, unconfounded, truly randomised controlled trials comparing any calcium antagonist with control, within ten days of SAH onset. Eleven trials that met the inclusion criteria were included in the overview.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed trial quality. Trialists were contacted to obtain missing information.

MAIN RESULTS

We analysed 11 trials totalling 2804 randomized patients with subarachnoid haemorrhage (1376 in the treatment and 1428 in the control group). The drugs analyzed were: nimodipine (eight trials, 1574 patients), nicardipine (two trials, 954 patients), and AT877 (one trial, 276 patients). In 92% of the patients aneurysms were confirmed by angiography or autopsy. Overall, calcium antagonists significantly reduce the risk of poor outcome after subarachnoid haemorrhage: relative risk (RR) 0.82 (95% CI 0. 72-0.93); the absolute risk reduction was 5.1%, the corresponding number of patients needed to treat to prevent a single poor outcome event is 20. For oral nimodipine alone the RR was 0.69 (0.58-0.84). The RR of death on treatment with calcium antagonists was 0.94 (95% CI 0.80-1.10), that of ischaemic neurological deficits 0.67 (95% CI 0.59-0.76), and that of CT-scan documented cerebral infarction 0.80 (95% CI 0.71-0.89).

REVIEWER'S CONCLUSIONS

Calcium antagonists reduce the proportion of patients with poor outcome and ischemic neurological deficits after aneurysmal SAH; the risk reduction for case fatality alone is not statistically significant. The results for 'poor outcome' are statistically robust, but depend mainly on trials with oral nimodipine; the evidence for nicardipine and AT877 is inconclusive. The intermediate factors through which nimodipine exerts its beneficial effect after aneurysmal SAH remain uncertain.

A population-based study of transient ischemic attack incidence in Novosibirsk, Russia, 1987-1988 and 1996-1997

BACKGROUND AND PURPOSE

Population-based data on transient ischemic attack (TIA) incidence are scarce. This study defines incidence rates of first-ever TIA in Novosibirsk, Russia, during 1987-1997 and compares the incidence of first TIA with that of first stroke.

METHODS

This is a prospective registry population-based study of all new cases of TIA and stroke in an overall population of 455 765 residents of Novosibirsk. All new TIA and stroke incident cases (whether inpatient or outpatient) that occurred during 1987-1988 and 1996-1997 study periods were recorded and analyzed. A 95% CI was estimated for all age- and sex-specific strata.

RESULTS

During the 2 study periods, a total of 211 patients with first TIA were registered in the population studied. The crude annual TIA incidence rate per 100 000 residents was 16 (95% CI, 8 to 33) in 1987-1988 and 29 (95% CI, 9 to 87) in 1996-1997; these rates standardized to the European population were 17 (95% CI, 8 to 34) and 27 (95% CI, 9 to 79), respectively. Eighty-three percent of TIAs occurred in the carotid arteries (rate, 48/100 000), 10% occurred in the vertebrobasilar territory (rate, 6/100 000), and 7% of cases had a TIA of uncertain distribution (rate, 2/100 000).

CONCLUSIONS

Unlike stroke incidence rate, the incidence rate of TIA in Novosibirsk is similar to that in other populations and constitutes approximately 10% of stroke incidence. For the last decade (1987-1997), there was a tendency, although statistically insignificant, toward increasing incidence rate of TIA in the population studied.

Calcium antagonists in patients with aneurysmal subarachnoid hemorrhage: a systematic review

BACKGROUND AND PURPOSE

It has been reported that nimodipine reduces the frequency of secondary ischemia and improves outcome after aneurysmal SAH, but definitive evidence concerning all available calcium antagonists is lacking.

METHODS

Systematic overview of randomized trials that were completed by January 1996 compared calcium antagonists with control and started treatment within 10 days after onset of subarachnoid hemorrhage (SAH) was performed. All calcium antagonists studied thus far (nimodipine, nicardipine, and AT877) were included.

RESULTS

We analyzed 10 trials totaling 2756 patients. The relative risk (RR) reduction of poor outcome (death or dependency) was 16% (95% CI, 6 to 27%) and that of case fatality was 10% (95% CI, -6 to 25%). To prevent one poor outcome, 19 (12 to 59) patients need to be treated. Calcium antagonists give a 33% (95%, CI 25 to 41) RR reduction in the frequency of ischemic neurologic deficit and a 20% (95% CI, 11 to 28) RR reduction in the frequency of CT-scan documented cerebral infarction. Eight (6 to 11) patients need to be treated to prevent one ischemic neurologic deficit. In the analyses for nimodipine only, treatment was associated with a 24% RR reduction of poor outcome (95% CI, 12 to 38). To prevent one poor outcome, 13 (8 to 30) patients need to be treated with nimodipine. The RR reduction of angiographically detected cerebral vasospasm was statistically significant for AT877 (38%; 95% CI, 17 to 54%) and nicardipine (21%; 95% CI, 6 to 34%) but not for nimodipine (9%; 95% CI, -2 to 19%).

CONCLUSION

Calcium antagonists reduce the proportion of ischemic neurologic deficits and nimodipine improves overall outcome within 3 months of aneurysmal SAH; evidence for a reduction of poor outcome from all causes by nicardipine and AT877 is inconclusive. The intermediate factors by which nimodipine exerts its beneficial effect remain uncertain.

Risk factors for ischemic stroke in a Russian community: a population-based case-control study

BACKGROUND AND PURPOSE

This study was conducted to determine the risk factors for ischemic stroke in a defined Russian population.

METHODS

Our data are based on a population-based case-control study of 237 patients with first-ever ischemic stroke and 237 age- and sex-matched controls. Logistic regression methods for matched pairs were used to estimate the relative risk for the variables studied.

RESULTS

In a multivariate analysis, hypertension, left ventricular hypertrophy on electrocardiography, ischemic heart disease, mitral valve disease, current cigarette smoking, and high body mass index were significant and independent risk factors for ischemic stroke in this Russian community.

CONCLUSIONS

The significant risk factors for ischemic stroke in Novosibirsk are similar to those from other populations and cohorts. This study, the first of stroke risk factors in Russia, has implications for clinical practice and the planning of stroke prevention in the population.

Seasonal variation in the occurrence of ischemic stroke and subarachnoid hemorrhage in Siberia, Russia. A population-based study

Epidemiological studies on the relationship between stroke occurrence and the seasons in different countries produced inconsistent results and little is known about these associations in a general population. We report a population-based study of 214 patients with first-ever ischemic stroke (IS, data for 1992) and 64 patients with first-ever subarachnoid hemorrhage (SAH) registered in the 25-74 years old population of Oktiabrsky District of Novosibirsk, Russia in 1982-92. IS and SAH incidence in four seasons (winter, spring, summer, autumn) was evaluated by means of a chi-square test. Poisson regression analysis was used to compute the rate ratios (RRs) and corresponding confidence intervals (CIs) for the occurrence of IS and SAH in winter, spring, and autumn compared with summer. Seasonal variations in the occurrence of IS were significant for the group of young men (25-64 years) and the group of older women (65-74 years) only. The age and sex adjusted RR of the occurrence of IS in winter was 49% greater than in summer (95%CI 1-119%). When men and women were analyzed separately and the rates were adjusted for age, a significantly higher risk of IS was found only in men (RR = 2.48; 95% CI 1.27-4.83) in spring compared with summer. No seasonality was observed for the occurrence of SAH in both men and women. Our findings indicate that there is a significantly greater incidence of ischemic stroke during winter in Siberia, Russia, whereas the incidence of SAH does not show a seasonal variation.

Stroke epidemiology in Novosibirsk, Russia: a population-based study

OBJECTIVE

To determine first-ever stroke incidence, 30-day case-fatality rates, and frequency of various risk factors among patients with stroke in Novosibirsk, Russia, during 1992.

DESIGN

A population-based study of an administratively defined district of Novosibirsk was conducted to identify residents with a first-ever stroke that occurred between Jan. 1, 1992, and Dec. 31, 1992.

MATERIAL AND METHODS

For case ascertainment, mortality statistics, death certificates, hospital registrations, outpatient clinical data, and all ambulance calls for the study area were reviewed. Patients with stroke or suspected stroke were examined and interviewed by a cerebrovascular neurologist, and the type of stroke was determined.

RESULTS

During the 12-month study period, 366 patients with first-ever stroke were registered. A diagnosis of cerebral infarction or intracerebral hemorrhage was confirmed by computed tomography or autopsy in 42% of cases. The diagnosis of subarachnoid hemorrhage was established by cerebrospinal fluid examination in all 14 cases. The age- and sex-adjusted annual incidence rate for stroke was 232 per 100,000. The distribution of incidence cases by diagnostic category was as follows: cerebral infarction, 87.7%; intracerebral hemorrhage, 8.5%; and subarachnoid hemorrhage, 3.8%. The overall 30-day case-fatality rate for stroke was 22.4%. Hypertension, angina pectoris, and cigarette smoking were the most frequent risk factors in patients with stroke in Novosibirsk.

CONCLUSION

The incidence rate of first-ever stroke in Novosibirsk, Russia, is one of the highest in the world, but the 30-day case-fatality rates are similar to those in other populations.

Stroke incidence and 30-day case-fatality rates in Novosibirsk, Russia, 1982 through 1992

BACKGROUND AND PURPOSE

The present study was conducted to investigate the incidence of stroke and 30-day case-fatality rates for stroke in a defined Russian population.

METHODS

This is a population-based study that was established in 1982. All residents of an administratively defined and typical district of Novosibirsk (approximately 150,000 subjects) who had an incident (first-ever) stroke from January 1, 1982, through December 31, 1992, were registered.

RESULTS

During an 11-year study period, 3406 incident stroke patients were registered, for an overall crude average annual incidence rate of 202/100,000 population. The rates were higher with increasing age and were significantly higher for men than for women. The age- and sex-adjusted annual incidence rate of stroke declined from 271/100,000 in 1982 to 232/100,000 in 1992. Slowing of the decline in stroke incidence was observed after 1988, and stroke incidence increased slightly in 1992. No significant differences in 30-day stroke case-fatality rates were noted from 1982 through 1992, but a slight trend toward decreasing rates was observed after 1988. There was no major change in patient age at stroke onset.

CONCLUSIONS

Stroke incidence rates in Novosibirsk are among the highest in the world. We observed a decline in stroke incidence but little change in 30-day case-fatality rates in Novosibirsk from 1982 through 1992.