International trends in stroke mortality: 1970-1985

Stroke study group. Preliminary results. Early intensive care improves functional outcome

Early and intensive care seems to positively affect outcome in stroke patients. A standardized protocol, costly adjusted to our reality and suitable for application by non-specialist at Emergency Room, proved effective, reflecting in diagnosis reliability, reducing time for beginning therapy, leading to low mortality rates and better functional outcomes at discharge.

Changes in stroke incidence and case-fatality in Auckland, New Zealand, 1981-91

The explanation for the substantial decline in stroke death rates can be investigated only by measuring trends in stroke incidence and case-fatality. Two community-based studies carried out in Auckland, New Zealand, in 1981 and 1991 used comparable methods and definitions, met criteria for well-designed studies, and had the power to detect small changes in incidence and case-fatality rates. 703 events (representing 50% of all strokes) were registered in 1981 and 1735 events in 1991. 521 (74.1%) and 1255 (72.3%) events in 1981 and 1991, respectively, were first-ever (in a lifetime) strokes. Although there was no change in overall stroke incidence between 1981 and 1991, there were changes in age and sex groups. The incidence rate among women younger than 75 years rose by a fifth (rate ratio 1.23 [95% CI 1.04-1.47]), whereas that in men of 75 years and older fell by a third (rate ratio 0.67 [0.54-0.82]). The 28-day case-fatality declined from 27.1 (21.7-32.6)% to 21.9 (18.1-25.7)% in men and from 37.6 (31.8-43.5)% to 25.8 (22.3-29.4)% in women from 1981 to 1991, but the decline was not statistically significant in any age or sex group. These findings suggest that we need to reappraise strategies for the prevention of stroke and assess the implications of improved survival in elderly stroke patients.

[Trends of mortality from cerebrovascular disease in the State of São Paulo: 1970 to 1989]

AIM

description of proportional mortality and death rates by Stroke in adult population (20 years of age or older) of São Paulo State, Brazil.

METHODS

the deaths were obtained from the statistical official bureau; the population data were based in the Federal Census (1970, 1980 and 1991); all trends whose the slope was significantly greater than zero had a calculation of the decline per year.

RESULTS

proportional mortality for Stroke decreased for males (M) (-11.40%) and increased for females (F) (+7.58%); Stroke in all cardiovascular diseases showed increase in both sexes, +8.65% (M) and +3.12% (F); Stroke age-adjusted death rates declined 1.19% (M) per year and 1.76% (F) per year between 1970 and 1989; the ages whose decline was more important were those 60-years-old of age or older (M) and 40-years-old or older (F); the male/female sex ratio increased during the observed years (22% in 1970 to 45%) due to the change in the 50-59 age strata (36% in 1970 to 69% in 1989).

CONCLUSION

the fall of the Stroke deaths rates could be due to increase in the detection and control of hypertension; other factors such as improve in death certification, decline of Chagasic myocarditis, new image-diagnostic tests and medical care had maybe only a secondary play in the decline of stroke mortality.

The quality of epidemiological data in coronary heart disease and atherosclerosis

There are inherent difficulties in the use of indirect observations in the epidemiology of a chronic ubiquitous disease such as atherosclerosis. Such difficulties do not condone basic errors in epidemiological methodology, the use of low quality data, a lack of precision in measurements, invalid extrapolations and inappropriate use of terminology and coronary heart disease as a surrogate or synonym of coronary atherosclerosis and bias in the interpretation of data. These errors reveal a lack of rigorous and scientific standards in the epidemiology of coronary heart disease. Analysis cannot launder such data. Independent scientists must evaluate the data in respect of precision, logic and truth.

Trends in stroke mortality and incidence in Finland in the 1970s and 1980s

This article presents trends in stroke mortality and incidence in Finland among people aged 25 to 74 years. Between 1971 and 1980, stroke mortality declined steeply: 4.1% per year among men and 5.5% per year among women. Between 1981 and 1991 the decline was smaller; about 2.2% per year in men and 2.8% per year in women. The North Karelia stroke register showed that stroke mortality declined in men from 155 per 100,000 per year in 1972 to 1973, to 87 per 100,000 per year in 1982 to 1983, and in women from 114 to 44 per 100,000 per year. A slight decline in mortality was observed during the 1980s in men, but not in women. The incidence of stroke also declined in North Karelia during the 1970s, from 328 to 248 per 100,000 per year in men, and from 230 to 141 per 100,000 in women. In the FINMONICA stroke register, the average rate of decline in incidence of stroke between 1983 and 1989 was 1.7% per year in men and 1.8% per year in women. Declines in incidence and mortality from subarachnoid hemorrhage were observed in both men and women; nevertheless it was the decline in cerebral infarction that accounted for most of the changes since about 80% of all strokes are cerebral infarctions. In conclusion, despite steep falls in stroke mortality and incidence in the 1970s, stroke mortality is still high in Finland compared with other nations. During the 1980s, the decline in stroke mortality was less and incidence leveled off until it resumed from 1987 to 1989.(ABSTRACT TRUNCATED AT 250 WORDS)

Stroke trends in Australia and New Zealand: mortality, morbidity, and risk factors

Stroke death rates are declining in Australia and New Zealand as in many other industrialized countries. An explanation for the decline in mortality requires information from population-based incidence studies. Two studies that meet the criteria for well-designed stroke studies have been conducted, one in Auckland, New Zealand, in 1991 and the other in Perth, Western Australia, in 1988 to 1989. Comparisons between the two studies reveal similar incidence and case-fatality rates for both men and women, reflecting the similar mortality rates. The Auckland study repeats one carried out 10 years earlier and allows an insight into the changes in incidence, case fatality, and severity of stroke in a large urban population. Between the two study periods there was no overall change in the incidence rates but case-fatality rates improved in both men and women. Although there have been significant improvements in the level of smoking in both Australia and New Zealand during the 1980s, only marginal improvements in mean population blood pressure have occurred, despite efforts and resources directed at identification of individuals with raised blood pressure. This high-risk strategy has apparently had only a very limited impact on reducing the incidence of stroke in the population.

The decline in stroke mortality. An epidemiologic perspective

The evidence that treatment of hypertension prevents stroke is incontrovertible. Several observations, however, suggest that improvements in the prevalence of antihypertensive treatment cannot explain all of the recent decline in stroke mortality. Changes in nutritional patterns may explain some of the observed decline. Prospective studies have demonstrated conclusively an independent, increasing risk of hemorrhagic, but not thrombotic, stroke at higher levels of alcohol use. Stroke mortality is associated inversely with fat and protein intake. Dietary sodium has been linked to stroke in ecologic studies but not in prospective studies. Ecologic studies have suggested that foods high in vitamin C and potassium protect against stroke; an inverse association of potassium intake with fatal stroke has been demonstrated in cohort studies. Two studies in humans also suggest a protective effect of serum selenium against subsequent stroke. Determination of the influence of nutrients on stroke incidence offers tantalizing opportunities for future research and possibly, intervention.

Cerebrovascular disease at autopsy and in the death statistics for the county of Hordaland, Norway

Between 1975 and 1984 a decrease in deaths from cerebrovascular disorders was found both at autopsy and in the official mortality statistics. In the autopsy material (662 cases) the decrease was seen mainly in patients dying of cerebral hemorrhage. Concordance between autopsy and mortality statistics was best in the 30 to 79-year age group. Discordance rose with age, being highest in those above 80 years. This was mainly due to use of the diagnosis "undetermined vascular lesion" given as the clinical cause of death. The diagnosis was not upheld at autopsy. In such cases the presence of a cerebral lesion was rarely confirmed at autopsy. The decrease in acute cerebrovascular deaths was not accompanied by an increase in the number of patients in the category "stroke with sequelae", assessed as a fall in number. Thus mortality statistics can be directly misleading in geriatric patients; and the autopsy frequency in this age group is too low to give a satisfactory picture of events.

Ascertaining the true incidence of stroke: experience from the Perth Community Stroke Study, 1989-1990

OBJECTIVE

To determine the age and sex specific incidence, and case fatality of stroke in Perth, Western Australia.

DESIGN AND SETTING

A population-based descriptive epidemiological study.

SUBJECTS

All residents of a geographically defined segment of the Perth metropolitan area (population 138,708) who had a stroke or transient ischaemic attack between 20 February 1989 and 19 August 1990, inclusive.

MAIN OUTCOME MEASURES

Definite acute "first-ever-in-a-lifetime" (first-ever) and recurrent stroke classified according to standard definitions and criteria.

RESULTS

During the 18-month study period, 536 stroke events occurred among 492 patients, 69% of which were first-ever strokes. The crude annual event rate for all strokes was 258 (95% confidence interval 231-285) per 100,000, and the overall case fatality at 28 days was 24% (95% CI, 20%-28%). The crude annual incidence for first-ever strokes was 178 (95% CI, 156-200) per 100,000; 189 (95% CI, 157-221) per 100,000 in males and 166 (95% CI, 136-196) per 100,000 in females. The corresponding rates, age-adjusted to the "world" population, were 132 (95% CI, 109-155) for males and 77 (95% CI, 60-94) for females.

CONCLUSIONS

In contrast to mortality rates for ischaemic heart disease, the incidence of stroke in Australia appears little different from that for several other Western countries. For both males and females the incidence of stroke rises exponentially with increasing age. Although the sex-dependent difference in the risk of stroke is greatest in middle age, males are at greater risk of stroke even among the most elderly. To determine the incidence of stroke accurately, population-based studies of stroke need exhaustive and overlapping sources of case ascertainment. If only cases admitted to hospital had been used, we would have underestimated the rate of stroke among the most elderly by almost 40%. We estimate that approximately 37,000 people, about 50% of whom are over the age of 75, suffer a stroke each year in Australia.

Prevention of ischemic stroke: the role of carotid endarterectomy in symptomatic patients

Carotid endarterectomy (CE) has recently been proved to be beneficial in symptomatic patients with severe (70-99%) appropriate carotid stenosis. After discussing the historical evolution of CE as a possible preventive treatment of ischemic stroke, we review the results of North American and European trials in order to give practical information for the management of cerebrovascular patients.

Progetto ATENA, a study on the etiology of major chronic diseases in women: design, rationale and objectives

In spite of their important impact on populations, a number of diseases--all types of cancer and coronary heart disease in women--are "rare" events for statistical analysis and often analyzed in designs affected by selection and information biases, such as case-control studies. Large cohort studies based on the storage of biological specimens appear to be the most suitable solution for identifying risks for those diseases. Progetto ATENA, a study on the etiology of major chronic diseases in women is based on this design. Ten thousand women, aged 30-69 years, living in the area of the city of Naples, free of cancer and cardiovascular disease, are being recruited over a four-year period. Ten per cent of the cohort is being randomly selected from the electoral roles, the rest will be volunteers. Information on dietary habits, reproductive history, familiarity for chronic disease, active smoking habits and passive smoking exposure, physical activity, and socio-demographic data are being collected. Clinical data such as blood pressure, anthropometry, and electrocardiogram are also taken. All the participants provide biological samples of blood (fasting drawing) and urine (timed morning spot). The biological samples are processed in order to explore the main areas under study (nutritional markers, metabolism, endocrinology, genetics, environmental exposure markers, thrombogenesis). The samples are stored in liquid nitrogen (-196 degrees C) as soon as the blood and urine processing have been finished. An appropriate follow-up information system on the health status of the participants is being set up to estimate incidence and mortality rates.

Community demonstration programs for cardiovascular disease prevention: the Asia-Pacific experience

Cardiovascular diseases are an important and increasing cause of death in many countries in the Asia-Pacific Region. Formal demonstration programs for the prevention of cardiovascular disease are few in number and not likely to be widely used in the future. Prevention programs focused on key risk factors are widely used in the Region and have been successful. Smoking prevention remains a high priority for all countries in the Region.

Stroke prevention in women: role of aspirin versus ticlopidine

Stroke is the third leading cause of death in North America. Most studies indicate that women are just as likely as men to have an initial stroke but less likely to have a recurrent stroke. Aspirin and ticlopidine are two antiplatelet drugs that reduce the risk of recurrent stroke by 25% to 30%. In some stroke prevention trials, aspirin has been shown to be more effective for men than for women. In contrast, major stroke prevention trials using ticlopidine have demonstrated equal benefit in women and in men. The overall incidence of adverse effects seen with ticlopidine is not significantly different from that observed with aspirin. There are now two effective agents useful in stroke prevention in both men and women.

Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis

BACKGROUND

Without strong evidence of benefit, the use of carotid endarterectomy for prophylaxis against stroke rose dramatically until the mid-1980s, then declined. Our investigation sought to determine whether carotid endarterectomy reduces the risk of stroke among patients with a recent adverse cerebrovascular event and ipsilateral carotid stenosis.

METHODS

We conducted a randomized trial at 50 clinical centers throughout the United States and Canada, in patients in two predetermined strata based on the severity of carotid stenosis--30 to 69 percent and 70 to 99 percent. We report here the results in the 659 patients in the latter stratum, who had had a hemispheric or retinal transient ischemic attack or a nondisabling stroke within the 120 days before entry and had stenosis of 70 to 99 percent in the symptomatic carotid artery. All patients received optimal medical care, including antiplatelet therapy. Those assigned to surgical treatment underwent carotid endarterectomy performed by neurosurgeons or vascular surgeons. All patients were examined by neurologists 1, 3, 6, 9, and 12 months after entry and then every 4 months. End points were assessed by blinded, independent case review. No patient was lost to follow-up.

RESULTS

Life-table estimates of the cumulative risk of any ipsilateral stroke at two years were 26 percent in the 331 medical patients and 9 percent in the 328 surgical patients--an absolute risk reduction (+/- SE) 17 +/- 3.5 percent (P less than 0.001). For a major or fatal ipsilateral stroke, the corresponding estimates were 13.1 percent and 2.5 percent--an absolute risk reduction of 10.6 +/- 2.6 percent (P less than 0.001). Carotid endarterectomy was still found to be beneficial when all strokes and deaths were included in the analysis (P less than 0.001).

CONCLUSIONS

Carotid endarterectomy is highly beneficial to patients with recent hemispheric and retinal transient ischemic attacks or nondisabling strokes and ipsilateral high-grade stenosis (70 to 99 percent) of the internal carotid artery.