Citations

The three factors other than age that are the most important determinants of stroke occurrence are (1) transient cerebral ischemic attacks (TIAs), (2) hypertension, and (3) cardiac disease. In the Rochester population study, a stroke developed during the period of observation in 36% of the patients with TIAs. Fifty-one percent of all the strokes occurred during the first year after the TIA, and 21% occurred during the first month after the first attack. Hypertensive persons have an increased incidence of each of the major atherothrombotic diseases as compared to normotensive persons. During the full 25 years of study of the Rochester population, there was a decrease from the earliest to the latest five-year period of 32% for all strokes in women and 20% in men. This may reflect treatment of this population.

This study has attempted to identify all patients in the population of Rochester, Minnesota, who had stroke during the period 1955 through 1969, and to determine the course and survival of patients who have had stroke. Cerebral infarction from all causes, including embolic infarction, accounted for 79% of all strokes. Intracerebral hemorrhage accounted for 10% of the cases, and subarachnoid hemorrhage accounted for 6%. The average annual incidence rate for the 15 years of the study was 164 per 100,000 population per year. The rates for all strokes and for cerebral infarction were significantly higher for men than for women, except in the youngest age group. After the end of an earlier study, 1945 through 1954, the average annual incidence rate for all strokes decreased in each succeeding five-year interval and reached 141 during the period 1965 through 1969. The decrease in rates is apparent for all strokes and for cerebral infarction, and is more apparent for women than for men. The prevalence rate on January 1, 1960, and January 1, 1965, of about 700 per 100,000 population was higher than the rate for January 1, 1970, reflecting decreasing incidence rates. A study of the functioning capacity of survivors of stroke after six months indicates that only 4% required total care and nearly 30% were functioning normally. Fifty-four percent had some neurological deficit that may have been benefited by rehabilitative care. Aphasia was an important residual incapacity in 10%. The first-year recurrence rate of stroke was 10%, and the five-year recurrence rate was 20%. Among patients with stroke who died, 38% died of the initial stroke, 10% of a subsequent stroke, and 18% of heart disease. During the 25-year period, 1945 through 1969, there has been a trend toward gradually increasing survival for cerebral infarction in this community.

Background and Purpose —There are few population-based data available regarding nursing home use after stroke. This study clarifies the use of a nursing home after stroke, as well as its dependence on stroke severity, in a defined population. Methods —All first stroke events among residents of Rochester, Minn, during 1987–1989 were ascertained, subtyped, and assigned Rankin disability scores (RS) before the event, at maximal deficit, and at specified intervals after stroke. Persons were followed from the date of stroke event to death, emigration from Rochester, or December 31, 1994, in complete community-based medical records and Minnesota Case Mix Review Program data tapes to determine nursing home residency before stroke and at 90 days and 1 year after stroke, proportion of survival days in a nursing home, and cumulative risk of admission to a nursing home. Results —There were 251 cases of first cerebral infarction, 24 intracerebral hemorrhages, and 15 subarachnoid hemorrhages among residents of Rochester during 1987–1989. The maximal deficit RS was 1 or 2 for 62 (25%), RS 3 for 72 (29%), and RS 4 or 5 for 117 (47%) of the cerebral infarct patients. Among patients surviving to 90 days or 1 year after cerebral infarction, 25% were in nursing home at 90 days and 22% at 1 year, respectively. Within these maximal deficit RS categories, the percentages of follow-up time spent in a nursing home during the first post–cerebral infarction year are as follows: RS 1 to 2, 4%; RS 3, 10%; and RS 4 to 5, 54%. Multivariate logistic regression revealed that increasing age and RS 4 to 5 at maximal deficit were independent predictors ( P <0.0001) of nursing home residency at 90 days and 1 year after stroke, whereas stroke type was not an independent predictor. At 1 year after cerebral infarction, the Kaplan-Meier estimates of proportion of people with at least 1 nursing home admission were 11% for RS 1 to 2, 22% for RS 3, and 68% for RS 4 to 5. Conclusions —This study provides unique population-based data regarding the short- and long-term use of a nursing home after stroke and its dependence on stroke severity. More than 50% of people with a severe cerebral infarction are in a nursing home 90 days and 1 year after the stroke, and by 1 year, nearly 70% will have required some nursing home stay. Age and stroke severity are independent predictors of nursing home residency after stroke.

Background and Purpose Despite growing concern over the large numbers of specialists in the United States, little information is available on how stroke treatment varies by the specialty of the attending physician. This study compares the costs and outcomes of acute stroke patients by physician specialty, especially between neurologists and other specialists. Methods We selected a random sample of Medicare patients aged 65 years and older admitted with cerebral infarction between January 1 and September 30, 1991, identified from the principal diagnosis on Medicare Provider Analysis and Review records. All Medicare claims for these patients were extracted from the date of admission through 90 days. The attending physician was identified as that physician billing for routine hospital visits during the first 7 days of the stay. Results Neurologists treating stroke patients were significantly more expensive than other physicians but obtained better outcomes. Ninety-day mortality rates for patients treated by neurologists were significantly lower than those for other specialists. These cost and outcome differences persisted even after adjustment for patient age, comorbidity, hospital teaching status, and other characteristics. Compared with other attending physicians, neurologists were significantly more likely to order diagnostic cerebrovascular tests (especially brain MRI scans), more likely to prescribe warfarin, and more likely to discharge patients to inpatient rehabilitation facilities. Conclusions Systematic triaging to neurologists based on clinical characteristics unmeasured by administrative data might explain these observed differences between neurologists and other physicians. Alternatively, these specialists may have been better able to identify the mechanism of stroke, information that then affected the course of treatment. Given current pressures to substitute generalists for specialists, however, more research is needed on these stroke treatment differences.

Cervical internal carotid artery dissections are diagnosed with an increasing frequency, but reliable epidemiologic data are not available. The aim of this study was to determine the incidence rate of spontaneous cervical internal carotid artery dissection in a defined population. Using the medical record linkage system used for epidemiologic studies in Rochester, Minn, all patients diagnosed with spontaneous cervical ICA dissection for 1987 through 1992 were identified. A total of 10 patients with spontaneous cervical internal carotid artery dissection (6 women and 4 men; mean age, 44 years) were identified. For the period 1987 through 1992, the average annual incidence rate for all ages was 2.6 per 100,000 (95% confidence intervals, 0.9 to 4.2). This study, for the first time, provides incidence rates for spontaneous cervical internal carotid artery dissections. No diagnoses were made before 1987, probably reflecting an increased awareness of the disorder among physicians.

Background and Purpose —There is scant population-based information on functional outcome, survival, and recurrence for ischemic stroke subtypes. Methods —We identified all residents of Rochester, Minnesota, with a first ischemic stroke from 1985 through 1989 using the resources of the Rochester Epidemiology Project medical records linkage system. After reviewing medical records and imaging studies, we assigned patients to 4 major ischemic stroke categories based on National Institute of Neurological Diseases and Stroke Data Bank criteria: large-vessel cervical or intracranial atherosclerosis with stenosis (ATH, n=74), cardioembolic (CE, n=132), lacunar (LAC, n=72), and infarct of uncertain cause (IUC, n=164). We used the Rankin disability score to assess functional outcome and the Kaplan-Meier product-limit method and Cox proportional hazards regression analysis with bootstrap validation to estimate rates and identify predictors of survival and recurrent stroke among these patients. Results —Rankin disabilities were different across stroke subtypes at the time of stroke and 3 months and 1 year later ( P =0.001). LAC was associated with milder deficits compared with other subtypes. Mean follow-up among the 442 patients in the cohort was 3.2 years. Estimated rates of recurrent stroke at 30 days were significantly different ( P <0.001): ATH, 18.5% (95% CI 9.4% to 27.5%); CE, 5.3% (95% CI 1.2% to 9.6%); LAC, 1.4% (95% CI 0.0% to 4.1%); and IUC, 3.3% (95% CI 0.4% to 6.2%). After adjusting for age, sex, and stroke severity, infarct subtype was an independent determinant of recurrent stroke within 30 days ( P =0.0006; eg, risk ratio for ATH compared with CE=3.3, 95% CI 1.2 to 9.3) but not long term ( P =0.07). Four of 25 recurrent strokes within 30 days were procedure-related, each in patients with ATH. Five-year death rates were significantly different ( P <0.001): ATH, 32.2% (95% CI 21.1% to 43.2%); CE, 80.4% (95% CI 73.1% to 87.6%); LAC, 35.1% (95% CI 23.6% to 46.0%); and IUC, 48.6% (95% CI 40.5% to 56.7%). With adjustment for age, sex, cardiac comorbidity, and stroke severity, the subtype of ischemic stroke was an independent determinant of long-term ( P =0.018; eg, risk ratio for ATH compared with cardioembolic=0.47, 95% CI 0.29 to 0.77) but not 30-day survival ( P =0.2). Conclusions —Early recurrence rates for ischemic stroke caused by ATH are higher than those for other subtypes and higher than previous non–population-based studies have reported. Some of the increased risk of early recurrence among patients with ATH may be iatrogenic. Patients with LAC have better poststroke functional status than those with other subtypes. Survival is poorest among those with ischemic stroke with a cardiac source of embolism.

Background and Purpose —There is little population-based information on cerebrovascular events and survival among valvular heart disease patients. We used the Kaplan-Meier product-limit method and the Cox proportional hazards model to determine rates and predictors of cerebrovascular events and death among valve disease patients. Methods —This population-based historical cohort study in Olmsted County, Minnesota, reviewed residents with a first echocardiographic diagnosis of mitral stenosis (n=19), mitral regurgitation (n=528), aortic stenosis (n=140), and aortic regurgitation (n=106) between 1985 and 1992. Results —During 2694 person-years of follow-up, 98 patients developed cerebrovascular events and 356 died. Compared with expected numbers, these observations are significantly elevated, with standardized morbidity ratio of 3.2 (95% CI, 2.6 to 3.8) and 2.5 (95% CI, 2.2 to 2.7), respectively. Independent predictors of cerebrovascular events were age, atrial fibrillation, and severe aortic stenosis. The risk ratio of severe aortic stenosis was 3.5 (95% CI, 1.4 to 8.6), with atrial fibrillation conferring greater risk at younger age. Predictors of death were age, sex, cerebrovascular events, ischemic heart disease, and congestive heart failure, the greatest risk being among those with both congestive heart failure and cerebrovascular events (risk ratio=8.8; 95% CI, 5.8 to 13.4). Valve disease type and severity were not independent determinants of death. Conclusions —The risk of cerebrovascular events and death among patients with valve disease remains high. Age, atrial fibrillation, and severe aortic stenosis are independent predictors of cerebrovascular events, and age, sex, cerebrovascular events, congestive heart failure, and ischemic heart disease are independent predictors of death in these patients.

Background and Purpose —There is scant information available on the incidence of transient ischemic attack (TIA) in a defined population. This study defines incidence rates of first TIA and subtypes of TIA during 1985–1989 and compares the incidence to that obtained from a 1960–1972 cohort study. Methods —Medical records of all residents of Rochester with potential diagnosis of TIA during 1985–1989 were screened to determine whether the case met the criteria for TIA. All available data were used to determine the vascular distribution of the TIA. Average annual age- and sex-adjusted incidence rates were calculated for 1985–1989, and results were compared with incidence rates determined in a Rochester-based 1960–1972 cohort study. Results —Two hundred two cases of first TIA or amaurosis fugax occurred among Rochester residents during 1985–1989. The age- and sex-adjusted incidence rate for any TIA was 68/100 000 population. Incidence of amaurosis fugax was 13/100 000; anterior circulation (cerebral) TIA, 38/100 000; and vertebrobasilar distribution TIA, 14/100 000. Rates were similar to those determined from a 1960–1972 cohort study. Conclusions —The incidence rate of TIA is 41% that of stroke incidence. TIA incidence in Rochester, Minn, is higher than has been previously reported for other sites throughout the world. Although comparison with prior time periods is difficult because of ascertainment issues, it appears that there has been no significant change in TIA incidence since the decade of the 1960s or earlier. This suggests that the most common mechanism for TIA (atherosclerosis) has not changed in prevalence, nor have risk factors leading to this mechanism.

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.