Age, Sex, and Racial Differences in Neuroimaging Use in Acute Stroke: A Population-Based Study.

BACKGROUND AND PURPOSE: Limited information is available regarding differences in neuroimaging use for acute stroke work-up. Our objective was to assess whether race, sex, or age differences exist in neuroimaging use and whether these differences depend on the care center type in a population-based study. MATERIALS AND METHODS: Patients with stroke (ischemic and hemorrhagic) and transient ischemic attack were identified in a metropolitan, biracial population using the Greater Cincinnati/Northern Kentucky Stroke Study in 2005 and 2010. Multivariable regression was used to determine the odds of advanced imaging use (CT angiography/MR imaging/MR angiography) for race, sex, and age. RESULTS: In 2005 and 2010, there were 3471 and 3431 stroke/TIA events, respectively. If one adjusted for covariates, the odds of advanced imaging were higher for younger (55 years or younger) compared with older patients, blacks compared with whites, and patients presenting to an academic center and those seen by a stroke team or neurologist. The observed association between race and advanced imaging depended on age; in the older age group, blacks had higher odds of advanced imaging compared with whites (odds ratio, 1.34; 95% CI, 1.12-1.61; P < .01), and in the younger group, the association between race and advanced imaging was not statistically significant. Age by race interaction persisted in the academic center subgroup (P < .01), but not in the nonacademic center subgroup (P = .58). No significant association was found between sex and advanced imaging. CONCLUSIONS: Within a large, biracial stroke/TIA population, there is variation in the use of advanced neuroimaging by age and race, depending on the care center type.

Greater Cincinnati/Northern Kentucky Stroke Study: volume of first-ever ischemic stroke among blacks in a population-based study.

BACKGROUND AND PURPOSE: The volume of ischemic stroke on CT scans has been studied in a standardized fashion in acute stroke therapy trials with median volumes between 10.5 to 55 cm(3). The volume of first-ever ischemic stroke in the population is not known. METHODS: The first phase of the population-based Greater Cincinnati/Northern Kentucky Stroke Study identified all ischemic strokes occurring in blacks in the greater Cincinnati region between January and June of 1993. The patients in this phase of the study who had a first-ever ischemic clinical stroke were identified, and the volume of ischemic stroke was measured. RESULTS: There were 257 verified clinical cases of ischemic stroke, of which 181 had a first-ever ischemic infarct. Imaging was available for 150 of these patients, and 79 had an infarct on the CT or MRI study that was definitely or possibly related to the clinical symptoms. For these patients, volumetric measurements were performed by means of the modified ellipsoid method. The median volume of first-ever ischemic stroke for the 79 patients was 2.5 cm(3) (interquartile range, 0.5 to 8.8 cm(3)). There was a significant relation between location of lesion and infarct size (P<0.001) and between volume and mechanism of stroke (P=0.001). CONCLUSIONS: The volume of first-ever ischemic stroke among blacks in our population-based study is smaller than has been previously reported in acute stroke therapy trials. The large proportion of small, mild strokes in blacks may be an important reason for the low percentage of patients who meet the inclusion criteria for tissue plasminogen activator. Further study is necessary to see if these results are generalizable to a multiracial population.

The adverse effect of spasticity on 3-month poststroke outcome using a population-based model.

Several devices and medications have been used to address poststroke spasticity. Yet, spasticity's impact on outcomes remains controversial. Using data from a cohort of 460 ischemic stroke patients, we previously published a validated multivariable regression model for predicting 3-month modified Rankin Score (mRS) as an indicator of functional outcome. Here, we tested whether including spasticity improved model fit and estimated the effect spasticity had on the outcome. Spasticity was defined by a positive response to the question "Did you have spasticity following your stroke?" on direct interview at 3 months from stroke onset. Patients who had expired by 90 days (n = 30) or did not have spasticity data available (n = 102) were excluded. Spasticity affected the 3-month functional status (ß = 0.420, 95 CI = 0.194 to 0.645) after accounting for age, diabetes, leukoaraiosis, and retrospective NIHSS. Using spasticity as a covariable, the model's R (2) changed from 0.599 to 0.622. In our model, the presence of spasticity in the cohort was associated with a worsened 3-month mRS by an average of 0.4 after adjusting for known covariables. This significant adverse effect on functional outcomes adds predictive value beyond previously established factors.

Population-based study of wake-up strokes.

OBJECTIVE: Previous studies have estimated that wake-up strokes comprise 8%to 28% of all ischemic strokes, but these studies were either small or not population-based. We sought to establish the proportion and event rate of wake-up strokes in a large population-based study and to compare patients who awoke with stroke symptoms with those who were awake at time of onset. METHODS: First-time and recurrent ischemic strokes among residents of the Greater Cincinnati/Northern Kentucky region (population 1.3 million) in 2005 were identified using International Classification of Diseases-9 codes 430-436 and verified via study physician review. Ischemic strokes in patients aged 18 years and older presenting to an emergency department were included. Baseline characteristics were ascertained, along with discharge modified Rankin Scale scores and 90-day mortality. RESULTS: We identified 1,854 ischemic strokes presenting to an emergency department, of which 273 (14.3%) were wake-up strokes. There were no differences between wake-up strokes and all other strokes with regard to clinical features or outcomes except for minor differences in age and baseline retrospective NIH Stroke Scale score. The adjusted wake-up stroke event rate was 26.0/100,000. Of the wake-up strokes, at least 98 (35.9%) would have been eligible for thrombolysis if arrival time were not a factor. CONCLUSIONS: Within our population, approximately 14% of ischemic strokes presenting to an emergency department were wake-up strokes. Wake-up strokes cannot be distinguished from other strokes by clinical features or outcome. We estimate that approximately 58,000 patients with wake-up strokes presented to an emergency department in the United States in 2005.

The increasing incidence of anticoagulant-associated intracerebral hemorrhage.

OBJECTIVE: To define temporal trends in the incidence of anticoagulant-associated intracerebral hemorrhage (AAICH) during the 1990s and relate them to rates of cardioembolic ischemic stroke. METHODS: We identified all patients hospitalized with first-ever intracerebral hemorrhage (ICH) in greater Cincinnati during 1988, from July 1993 through June 1994, and during 1999. AAICH was defined as ICH in patients receiving warfarin or heparin. Patients from the same region hospitalized with first-ever ischemic stroke of cardioembolic mechanism were identified during 1993/1994 and 1999. Incidence rates were calculated and adjusted to the 2000 US population. Estimates of warfarin distribution in the United States were obtained for the years 1988 through 2004. RESULTS: AAICH occurred in 9 of 184 ICH cases (5%) in 1988, 23 of 267 cases (9%) in 1993/1994, and 54 of 311 cases (17%) in 1999 (p < 0.001). The annual incidence of AAICH per 100,000 persons was 0.8 (95% CI 0.3 to 1.3) in 1988, 1.9 (1.1 to 2.7) in 1993/1994, and 4.4 (3.2 to 5.5) in 1999 (p < 0.001 for trend). Among persons aged > or =80, the AAICH rate increased from 2.5 (0 to 7.4) in 1988 to 45.9 (25.6 to 66.2) in 1999 (p < 0.001 for trend). Incidence rates of cardioembolic ischemic stroke were similar in 1993/1994 and 1999 (31.1 vs 30.4, p = 0.65). Warfarin distribution in the United States quadrupled on a per-capita basis between 1988 and 1999. CONCLUSIONS: The incidence of anticoagulant-associated intracerebral hemorrhage quintupled in our population during the 1990s. The majority of this change can be explained by increasing warfarin use. Anticoagulant-associated intracerebral hemorrhage now occurs at a frequency comparable to subarachnoid hemorrhage.