Incidence and Case Fatality at the County Level as Contributors to Geographic Disparities in Stroke Mortality

Temporal Trends and Racial Disparities in Long-Term Survival After Stroke

BACKGROUND AND OBJECTIVES

Few studies have examined trends and disparities in long-term outcome after stroke in a representative US population. We used a population-based stroke study in the Greater Cincinnati Northern Kentucky region to examine trends and racial disparities in poststroke 5-year mortality.

METHODS

All patients with acute ischemic strokes (AISs) and intracerebral hemorrhages (ICHs) among residents ≥20 years old were ascertained using ICD codes and physician-adjudicated using a consistent case definition during 5 periods: July 1993-June 1994 and calendar years 1999, 2005, 2010, and 2015. Race was obtained from the medical record; only those identified as White or Black were included. Premorbid functional status was assessed using the modified Rankin Scale, with a score of 0-1 being considered "good." Mortality was assessed with the National Death Index. Trends and racial disparities for each subtype were analyzed with logistic regression.

RESULTS

We identified 8,428 AIS cases (19.3% Black, 56.3% female, median age 72) and 1,501 ICH cases (23.5% Black, 54.8% female, median age 72). Among patients with AIS, 5-year mortality improved after adjustment for age, race, and sex (53% in 1993/94 to 48.3% in 2015, overall effect of study year p = 0.009). The absolute decline in 5-year mortality in patients with AIS was larger than what would be expected in the general population (5.1% vs 2.8%). Black individuals were at a higher risk of death after AIS (odds ratio [OR] 1.23, 95% CI 1.08-1.39) even after adjustment for age and sex, and this effect was consistent across study years. When premorbid functional status and comorbidities were included in the model, the primary effect of Black race was attenuated but race interacted with sex and premorbid functional status. Among male patients with a good baseline functional status, Black race remained associated with 5-year mortality (OR 1.4, 95% CI 1.1-1.7, p = 0.002). There were no changes in 5-year mortality after ICH over time (64.4% in 1993/94 to 69.2% in 2015, overall effect of study year p = 0.32).

DISCUSSION

Long-term survival improved after AIS but not after ICH. Black individuals, particularly Black male patients with good premorbid function, have a higher mortality after AIS, and this disparity did not change over time.

Sherman Lecture: Are We Aiming at the Correct Targets to Reduce Disparities in Stroke Mortality? Celebration, Reflection, and Redirection

Although deaths from stroke have been reduced by 75% in the past 54 years, there has been virtually no reduction in the relative magnitude of Black-to-White disparity in stroke deaths, or the heavier burden of stroke deaths in the Stroke Belt region of the United States. Furthermore, although the rural-urban disparity has decreased in the past decade, this reduction is largely attributable to an increased stroke mortality in the urban areas, rather than reduced stroke mortality in rural areas. We need to focus our search for interventions to reduce disparities on those that benefit the disadvantaged populations, and support this review using relatively recently developed statistical approaches to estimate the magnitude of the potential reduction in the disparities.

Social Determinants of Stroke Hospitalization and Mortality in United States' Counties

(1) Background: Stroke incidence and outcomes are influenced by socioeconomic status. There is a paucity of reported population-level studies regarding these determinants. The goal of this ecological analysis was to determine the county-level associations of social determinants of stroke hospitalization and death rates in the United States. (2) Methods: Publicly available data as of 9 April 2021, for the socioeconomic factors and outcomes, was extracted from the Centers for Disease Control and Prevention. The outcomes of interest were “all stroke hospitalization rates per 1000 Medicare beneficiaries” (SHR) and “all stroke death rates per 100,000 population” (SDR). We used a multivariate binomial generalized linear mixed model after converting the outcomes to binary based on their median values. (3) Results: A total of 3226 counties/county-equivalents of the states and territories in the US were analyzed. Heart disease prevalence (odds ratio, OR = 2.03, p < 0.001), blood pressure medication nonadherence (OR = 2.02, p < 0.001), age-adjusted obesity (OR = 1.24, p = 0.006), presence of hospitals with neurological services (OR = 1.9, p < 0.001), and female head of household (OR = 1.32, p = 0.021) were associated with high SHR while cost of care per capita for Medicare patients with heart disease (OR = 0.5, p < 0.01) and presence of hospitals (OR = 0.69, p < 0.025) were associated with low SHR. Median household income (OR = 0.6, p < 0.001) and park access (OR = 0.84, p = 0.016) were associated with low SDR while no college degree (OR = 1.21, p = 0.049) was associated with high SDR. (4) Conclusions: Several socioeconomic factors (e.g., education, income, female head of household) were found to be associated with stroke outcomes. Additional research is needed to investigate intermediate and potentially modifiable factors that can serve as targeted interventions.

The significant places of African American adults and their perceived influence on cardiovascular disease risk behaviors

BACKGROUND

AA living in rural areas of the southeastern U.S. experience a disproportionate burden of cardiovascular disease (CVD) morbidity and mortality. Neighborhood environmental factors contribute to this disparity and may decrease the effectiveness of lifestyle interventions aimed at preventing CVD. Furthermore, the influence of neighborhood factors on AA CVD risk behaviors (i.e. physical activity) may be obscured by the use of researcher-defined neighborhoods and researcher-defined healthy and unhealthy places. The objective of this study was to elucidate the effects of neighborhood environments on AA CVD risk behaviors among AA adults who recently completed a lifestyle intervention. We specifically sought to identify AA adults' self-perceived places of significance and their perceptions of how these places impact CVD risk behaviors including diet, physical activity and smoking.

METHODS

We conducted semi-structured interviews with AA adults (N = 26) living in two rural North Carolina counties (Edgecombe and Nash, North Carolina, USA). Participants were recruited from a community-based behavioral CVD risk reduction intervention. All had at least one risk factor for CVD. Participants identified significant places including where they spent the most time, meaningful places, and healthy and unhealthy places on local maps. Using these maps as a reference, participants described the impact of each location on their CVD risk behaviors. Data were transcribed verbatim and coded using NVivo 12.

RESULTS

The average age of participants was 63 (SD = 10) and 92% were female. Places participants defined as meaningful and places where they spent the most time included churches and relatives' homes. Healthy places included gyms and parks. Unhealthy places included fast food restaurants and relatives' homes where unhealthy food was served. Place influenced CVD risk behaviors in multiple ways including through degree of perceived control over the environment, emotional attachment and loneliness, caretaking responsibilities, social pressures and social support.

CONCLUSIONS

As we seek to improve cardiovascular interventions for rural AA in the American South, it will be important to further assess the effect of significant places beyond place of residence. Strategies which leverage or modify behavioral influences within person-defined significant places may improve the reach and effectiveness of behavioral lifestyle interventions.

Joint mapping of cardiovascular diseases: comparing the geographic patterns in incident acute myocardial infarction, stroke and atrial fibrillation, a Danish register-based cohort study 2014-15

BACKGROUND

Disease mapping aims at identifying geographic patterns in disease. This may provide a better understanding of disease aetiology and risk factors as well as enable targeted prevention and allocation of resources. Joint mapping of multiple diseases may lead to improved insights since e.g. similarities and differences between geographic patterns may reflect shared and disease-specific determinants of disease. The objective of this study was to compare the geographic patterns in incident acute myocardial infarction (AMI), stroke and atrial fibrillation (AF) using the unique, population-based Danish register data.

METHODS

Incident AMI, stroke and AF was modelled by a multivariate Poisson model including a disease-specific random effect of municipality modelled by a multivariate conditionally autoregressive (MCAR) structure. Analyses were adjusted for age, sex and income.

RESULTS

The study included 3.5 million adults contributing 6.8 million person-years. In total, 18,349 incident cases of AMI, 28,006 incident cases of stroke, and 39,040 incident cases of AF occurred. Estimated municipality-specific standardized incidence rates ranged from 0.76 to 1.35 for AMI, from 0.79 to 1.38 for stroke, and from 0.85 to 1.24 for AF. In all diseases, geographic variation with clusters of high or low risk of disease after adjustment was seen. The geographic patterns displayed overall similarities between the diseases, with stroke and AF having the strongest resemblances. The most notable difference was observed in Copenhagen (high risk of stroke and AF, low risk of AMI). AF showed the least geographic variation.

CONCLUSION

Using multiple-disease mapping, this study adds to the results of previous studies by enabling joint evaluation and comparison of the geographic patterns in AMI, stroke and AF. The simultaneous mapping of diseases displayed similarities and differences in occurrence that are non-assessable in traditional single-disease mapping studies. In addition to reflecting the fact that AF is a strong risk factor for stroke, the results suggested that AMI, stroke and AF share some, but not all environmental risk factors after accounting for age, sex and income (indicator of lifestyle and health behaviour).

Rural-Urban Disparities in Intracerebral Hemorrhage Mortality in the USA: Preliminary Findings from the National Inpatient Sample

Objectives

To compare in-hospital mortality between intracerebral hemorrhage (ICH) patients in rural hospitals to those in urban hospitals of the USA.

Methods

We used the National Inpatient Sample to retrospectively identify all cases of ICH in the USA over the period 2004–2014. We used multivariable-adjusted models to compare odds of mortality between rural and urban hospitals. Joinpoint regression was used to evaluate trends in age- and sex-adjusted mortality in rural and urban hospitals over time.

Results

From 2004 to 2014, 5.8% of ICH patients were admitted in rural hospitals. Rural patients were older (mean [SE] 76.0 [0.44] years vs. 68.8 [0.11] years in urban), more likely to be white and have Medicare insurance. Age- and sex-adjusted mortality was greater in rural hospitals (32.2%) compared to urban patients (26.5%) (p value < 0.001). After multivariable adjustment, patients hospitalized in rural hospitals had two times the odds of in-hospital death compared to patients in urban hospitals (OR 2.07, 95% CI 1.77–2.41. p value < 0.001). After joinpoint regression, mortality declined in urban hospitals by an average of 2.8% per year (average annual percentage change, [AAPC] − 2.8%, 95% CI − 3.7 to − 1.8%), but rates in rural hospitals remained unchanged (AAPC − 0.54%, 95% CI − 1.66 to 0.58%).

Conclusions

Despite current efforts to reduce disparity in stroke care, ICH patients hospitalized in rural hospitals had two times the odds of dying compared to those in urban hospitals. In addition, the ICH mortality gap between rural and urban centers is increasing. Further studies are needed to identify and reverse the causes of this disparity.

Electronic supplementary material

The online version of this article (10.1007/s12028-020-00950-2) contains supplementary material, which is available to authorized users.

Geographic Variations of Stroke Incidence in Chinese Communities: An 18-Year Prospective Cohort Study from 1997 to 2015

Background and Purpose

As a leading cause of disability and death in China, stroke as well as its epidemiologic features have gained increasing attention. Prior studies, however, have overgeneralized the north-to-south gradient in China. Whether the differences exist across urban and rural areas remains unexplored. This study therefore aims to investigate the north-to-south gradient in stroke incidence across urban and rural China.

Methods

The present prospective cohort study analyzed data from the China Health and Nutrition Survey 1997 to 2015. By including 16,917 individuals from diverse social contexts, we calculated the age-standardized incidence of stroke across regions and the age-adjusted risk ratio (aRR). Cox proportional hazards models with time-varying covariates were employed to analyze variations in incident stroke.

Results

During the follow-up, age-standardized incidence of stroke ranged from 4.17 per 1,000 person-years (95% confidence interval [CI], 3.38 to 4.96) in the north region to 1.95 (95% CI, 1.60 to 2.30) in the south region (aRR, 2.04; 95% CI, 1.58 to 2.64; P<0.001). The north-to-south gradient of stroke incidence was observed only in rural areas, but not in urban areas. Hierarchical modelling analyses further indicated that the regional differences could be mostly explained by the disparities in the prevalence of hypertension.

Conclusions

The present study extends the current evidence on the north-to-south gradient by demonstrating that the difference varied across urban and rural China. Our findings highlight the importance of hypertension management as the measure for alleviating regional differences in stroke incidence.

Sociodemographic Disparities in Long-Term Mortality Among Stroke Survivors in the United States

Background and Purpose- It is unclear whether disparities in mortality among stroke survivors exist long term. Therefore, the purpose of the current study is to describe rates of longer term mortality among stroke survivors (ie, beyond 30 days) and to determine whether socioeconomic disparities exist. Methods- This analysis included 1329 black and white participants, aged ≥45 years, enrolled between 2003 and 2007 in the REGARDS study (Reasons for Geographic and Racial Differences in Stroke) who suffered a first stroke and survived at least 30 days after the event. Long-term mortality among stroke survivors was defined in person-years as time from 30 days after a first stroke to date of death or censoring. Mortality rate ratios (MRRs) were used to compare rates of poststroke mortality by demographic and socioeconomic characteristics. Results- Among adults who survived ≥30 days poststroke, the age-adjusted rate of mortality was 82.3 per 1000 person-years (95% CI, 75.4-89.2). Long-term mortality among stroke survivors was higher in older individuals (MRR for 75+ versus <65, 3.2; 95% CI, 2.6-4.1) and among men than women (MRR, 1.3; 95% CI, 1.1-1.6). It was also higher among those with less educational attainment (MRR for less than high-school versus college graduate, 1.5; 95% CI, 1.1-1.9), lower income (MRR for <$20k versus >50k, 1.4; 95% CI, 1.1-1.9), and lower neighborhood socioeconomic status (SES; MRR for low versus high neighborhood SES, 1.4; 95% CI, 1.1-1.7). There were no differences in age-adjusted rates of long-term poststroke mortality by race, rurality, or US region. Conclusions- Rates of long-term mortality among stroke survivors were higher among individuals with lower SES and among those residing in neighborhoods of lower SES. These results emphasize the need for improvements in long-term care poststroke, especially among individuals of lower SES.

An exploratory investigation of geographic disparities of stroke prevalence in Florida using circular and flexible spatial scan statistics

BACKGROUND

Stroke is a major public health concern due to the morbidity and mortality associated with it. Identifying geographic areas with high stroke prevalence is important for informing public health interventions. Therefore, the objective of this study was to investigate geographic disparities and identify geographic hotspots of stroke prevalence in Florida.

MATERIALS AND METHODS

County-level stroke prevalence data for 2013 were obtained from the Florida Department of Health's Behavioral Risk Factor Surveillance System (BRFSS). Geographic clusters of stroke prevalence were investigated using the Kulldorff's circular spatial scan statistics (CSSS) and Tango's flexible spatial scan statistics (FSSS) under Poisson model assumption. Exact McNemar's test was used to compare the proportion of cluster counties identified by each of the two methods. Both Cohen's Kappa and bias adjusted Kappa were computed to assess the level of agreement between CSSS and FSSS methods of cluster detection. Goodness-of-fit of the models were compared using Cluster Information Criterion. Identified clusters and selected stroke risk factors were mapped.

RESULTS

Overall, 3.7% of adults in Florida reported that they had been told by a healthcare professional that they had suffered a stroke. Both CSSS and FSSS methods identified significant high prevalence stroke spatial clusters. However, clusters identified using CSSS tended to be larger than those identified using FSSS. The FSSS had a better fit than the CSSS. Most of the identified clusters are explainable by the prevalence distributions of the known risk factors assessed.

CONCLUSIONS

Geographic disparities of stroke risk exists in Florida with some counties having significant hotspots of high stroke prevalence. This information is important in guiding future research and control efforts to address the problem. Kulldorff's CSSS and Tango's FSSS are complementary to each other and should be used together to provide a more complete picture of the distributions of spatial clusters of health outcomes.

The Association of Early Life Factors and Declining Incidence Rates of Dementia in an Elderly Population of African Americans

Objectives

To explore the possible association of childhood residence, education levels, and occupation with declining incidence rates of dementia in 2 cohorts of elderly African Americans.

Methods

African Americans residing in Indianapolis without dementia were enrolled in 1992 and 2001 and evaluated every 2-3 years. The cohorts consist of 1,440 participants in 1992 and 1,835 participants in 2001 aged 70 years and older. Cox proportional hazard regression models were used to compare cohort differences in dementia and Alzheimer's disease (AD) risk.

Results

The 2001 cohort had significantly decreased risk of both incident dementia and AD (hazard ratio [HR]: 0.62/0.57 for dementia/AD). Years of education was associated with decreased risk of dementia (HR = 0.93; p = .0011). A significant interaction (p = .0477) between education and childhood rural residence was found for the risk of AD that higher education level is significantly associated with reduced AD risk (HR = 0.87) in participants with childhood rural residence, but no association in those with urban upbringing. The cohort difference for dementia rates were attenuated by adjusting for the 3 risk factors but remained significant (HR = 0.75; p = .04).

Discussion

These results emphasize the importance of early life factors including rural residence and education for the risk for dementia later in life.

Radiotherapy Exposure in Cancer Patients and Subsequent Risk of Stroke: A Systematic Review and Meta-Analysis

Background: Cancer patients who have undergone radiotherapy may have an increased risk of subsequent stroke. A clear and detailed understanding of this risk has not been established. Methods: A search for research articles published from January 1990 to November 2017 in the English language was conducted. Subsequent stroke risk in cancer survivors was compared using relative risk (RR) and 95% confidence intervals (CI) according to whether or not radiotherapy was given. Results: A total of 12 eligible studies were identified including 57,881 total patients. All studies were retrospective, as no prospective studies were identified. The meta-analysis revealed a higher overall risk of subsequent stroke in cancer survivors/patients given radiotherapy compared to those not given radiotherapy (RR: 2.09, 95% CI: 1.45, 3.16). In addition, compared to patients not given radiotherapy, there was an increased risk of subsequent stroke for radiotherapy treated patients with Hodgkin's lymphoma (RR: 2.81, 95% CI: 0.69, 4.93) or head/neck/brain/nasopharyngeal cancer (RR: 2.16, 95% CI: 1.16, 3.16), for patients younger than 40 years (RR: 3.53, 95% CI: 2.51, 4.97) or aged 40-49 years (RR: 1.23, 95% CI: 1.09, 1.45) and for patients treated in Asia (RR: 1.88, 95% CI: 1.48, 2.29), the United States (RR: 1.62, 95% CI: 1.01, 2.23), or in Europe (RR: 4.11, 95% CI 2.62, 6.45). Conclusions: The available literature indicates an approximate overall doubling of the subsequent stroke risk in cancer patients given radiotherapy. The elevated risk was generally statistically significant according to cancer type, baseline patient age and region or country where treatment was given. Caution is required in interpreting these findings due to the heterogeneity of populations represented and lack of standardization and completeness across published studies. Further, if real, we cannot conclude the extent to which patient, treatment and/or investigational factors are responsible for this apparent elevated risk. An objective and more detailed understanding of the risks of radiotherapy, and how to prevent them, is urgently required. It is the responsibility of all who provide cancer services to ensure that the experience of all their patients is documented and analyzed using quality registries.

Geographic Disparities in the Incidence of Stroke among Patients with Atrial Fibrillation in the United States

AIM

To determine whether regional variation in stroke incidence exists among individuals with AF.

METHODS

Using healthcare utilization claims from 2 large US databases, MarketScan (2007-2014) and Optum Clinformatics (2009-2015), and the 2010 US population as the standard, we estimated age-, sex-, race- (only in Optum) standardized stroke incidence rates by the 9 US census divisions. We also used Poisson regression to examine incidence rate ratios (IRR) of stroke and the probability of anticoagulation prescription fills across divisions.

RESULTS

Both databases combined included 970,683 patients with AF who experienced 15,543 strokes, with a mean follow-up of 23 months. In MarketScan, the age- and sex-standardized stroke incidence rate was highest in the Middle Atlantic and East South Central divisions at 3.8/1000 person-years (PY) and lowest in the West North Central at 3.2/1000 PY. The IRR of stroke and the probability of anticoagulation fills were similar across divisions. In Optum Clinformatics, the age-, sex-, and race-standardized stroke incidence rate was highest in the East North Central division at 5.0/1000 PY and lowest in the New England division at 3.3/1000 PY. IRR of stroke and the probability of anticoagulation fills differed across divisions when compared to New England.

CONCLUSIONS

These findings suggest regional differences in stroke incidence among AF patients follow a pattern that differs from the hypothesized trend found in the general population and that other factors may be responsible for this new pattern. Cross-database differences provide a cautionary tale for the identification of regional variation using health claims data.

Contributors to the Excess Stroke Mortality in Rural Areas in the United States

BACKGROUND AND PURPOSE

Stroke mortality is 30% higher in the rural United States. This could be because of either higher incidence or higher case fatality from stroke in rural areas.

METHODS

The urban-rural status of 23 280 stroke-free participants recruited between 2003 and 2007 in the REGARDS study (Reasons for Geographic and Racial Differences in Stroke) was classified using the Rural-Urban Commuting Area scheme as residing in urban, large rural town/city, or small rural town or isolated areas. The risk of incident stroke was assessed using proportional hazards analysis, and case fatality (death within 30 days of stroke) was assessed using logistic regression. Models were adjusted for demographics, traditional stroke risk factors, and measures of socioeconomic status.

RESULTS

After adjustment for demographic factors and relative to urban areas, stroke incidence was 1.23-times higher (95% confidence intervals, 1.01-1.51) in large rural town/cities and 1.30-times higher (95% confidence intervals, 1.03-1.62) in small rural towns or isolated areas. Adjustment for risk factors and socioeconomic status only modestly attenuated this association, and the association became marginally nonsignificant (P=0.071). There was no association of rural-urban status with case fatality (P>0.47).

CONCLUSIONS

The higher stroke mortality in rural regions seemed to be attributable to higher stroke incidence rather than case fatality. A higher prevalence of risk factors and lower socioeconomic status only modestly contributed to the increased risk of incident stroke risk in rural areas. There was no evidence of higher case fatality in rural areas.