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

Association between Heat Vulnerability Index and Stroke Severity

BACKGROUND

Socioeconomically disadvantaged neighborhoods are particularly vulnerable to heat-related illnesses. We aim to investigate the association between the heat vulnerability index (HVI), an established neighborhood-level metric of heat-related mortality risk, and acute ischemic stroke (AIS) severity.

METHODS

We conducted a retrospective analysis of consecutive AIS admissions to a comprehensive stroke center between 2012 and 2021. Stroke severity was defined upon admission based on the National Institutes of Health Stroke Scale (NIHSS). Demographic, socioeconomic, and clinical characteristics were extracted from electronic health records. HVI status was assigned using residential ZIP codes. Multivariable logistic regression analyses were performed.

RESULTS

Of 3429 AIS admissions, 1123 (32.8%) were from high-HVI (scores 4-5) neighborhoods and 868 (25.3%) had severe stroke (NIHSS score ≥ 10). In the multivariable regression model with stepwise selection, a high HVI was independently associated with severe stroke (adjusted odds ratio: 1.40 [95% confidence interval 1.16-1.69]).

CONCLUSIONS

The association between a high HVI and severe stroke underscores the importance of targeting policy interventions to mitigate heat-related illness in socioeconomically disadvantaged neighborhoods.

Reducing risk behaviours after stroke: An overview of reviews interrogating primary study data using the Theoretical Domains Framework

BACKGROUND

Lifestyle changes, in addition to preventive medications, optimise stroke secondary prevention. Evidence from systematic reviews support behaviour-change interventions post-stroke to address lifestyle-related risk. However, understanding of the theory-driven mediators that affect behaviour-change post-stroke is lacking.

METHODS

Electronic databases MEDLINE, Embase, Epistemonikos and Cochrane Library of Systematic Reviews were searched to March 2023 for systematic reviews addressing behaviour-change after stroke. Primary studies from identified systematic reviews were interrogated for evidence supporting theoretically-grounded interventions. Data were synthesized in new meta-analyses examining behaviour-change domains of the Theoretical Domains Framework (TDF) and secondary prevention outcomes.

RESULTS

From 71 identified SRs, 246 primary studies were screened. Only 19 trials (N = 2530 participants) were identified that employed theoretically-grounded interventions and measured associated mediators for behaviour-change. Identified mediators mapped to 5 of 14 possible TDF domains. Trial follow-up ranged between 1-12 months and no studies addressed primary outcomes of recurrent stroke or cardiovascular mortality and/or morbidity. Lifestyle interventions targeting mediators mapped to the TDF Knowledge domain may improve the likelihood of medication adherence (OR 6.08 [2.79, 13.26], I2 = 0%); physical activity participation (OR 2.97 [1.73, 5.12], I2 = 0%) and smoking cessation (OR 10.37 [3.22, 33.39], I2 = 20%) post-stroke, supported by low certainty evidence; Lifestyle interventions targeting mediators mapping to both TDF domains of Knowledge and Beliefs about Consequences may improve medication adherence post-stroke (SMD 0.36 [0.07, 0.64], I2 = 13%, very low certainty evidence); Lifestyle interventions targeting mediators mapped to Beliefs about Capabilities and Emotions domains may modulate low mood post-stroke (SMD -0.70 [-1.28, -0.12], I2 = 81%, low certainty evidence).

CONCLUSION

Limited theory-based research and use of behaviour-change mediators exists within stroke secondary prevention trials. Knowledge, Beliefs about Consequences, and Emotions are the domains which positively influence risk-reducing behaviours post-stroke. Behaviour-change interventions should include these evidence-based constructs known to be effective. Future trials should address cardiovascular outcomes and ensure adequate follow-up time.

Twenty-Year Disparity Trends in United States Stroke Death Rate by Age, Race/Ethnicity, Geography, and Socioeconomic Status

BACKGROUND AND OBJECTIVES

In 2017, the Centers for Disease Control and Prevention (CDC) issued an alert that, after decades of consistent decline, the stroke death rate levelled off in 2013, particularly in younger individuals and without clear origin. The objective of this analysis was to understand whether social determinants of health have influenced trends in stroke mortality.

METHODS

We performed a longitudinal analysis of county-level ischemic and hemorrhagic stroke death rate per 100,000 adults from 1999 to 2018 using a Bayesian spatiotemporally smoothed CDC dataset stratified by age (35-64 years [younger] and 65 years or older [older]) and then by county-level social determinants of health. We reported stroke death rate by county and the percentage change in stroke death rate during 2014-2018 compared with that during 2009-2013.

RESULTS

We included data from 3,082 counties for younger individuals and 3,019 counties for older individuals. The stroke death rate began to increase for younger individuals in 2013 (p < 0.001), and the slope of the decrease in stroke death rate tapered for older individuals (p < 0.001). During the 20-year period of our study, counties with a high social deprivation index and ≥10% Black residents consistently had the highest rates of stroke death in both age groups. Comparing stroke death rate during 2014-2018 with that during 2009-2013, larger increases in younger individuals' stroke death rate were seen in counties with ≥90% (vs <90%) non-Hispanic White individuals (3.2% mean death rate change vs 1.7%, p < 0.001), rural (vs urban) populations (2.6% vs 2.0%, p = 0.019), low (vs high) proportion of medical insurance coverage (2.9% vs 1.9%, p = 0.002), and high (vs low) substance abuse and suicide mortality (2.8 vs 1.9%, p = 0.008; 3.3% vs 1.5%, p < 0.001). In contrast to the younger individuals, in older individuals, the associations with increased death rates were with more traditional social determinants of health such as the social deprivation index, urban location, unemployment rate, and proportion of Black race and Hispanic ethnicity residents.

DISCUSSION

Improvements in the stroke death rate in the United States are slowing and even reversing in younger individuals and many US counties. County-level increases in stroke death rate were associated with distinct social determinants of health for younger vs older individuals. These findings may inform targeted public health strategies.

Interventions for Behaviour Change and Self-Management of Risk in Stroke Secondary Prevention: An Overview of Reviews

INTRODUCTION

Optimised secondary prevention strategies that include lifestyle change are recommended after stroke. While multiple systematic reviews (SRs) address behaviour change interventions, intervention definitions, and associated outcomes differ between reviews. This overview of reviews addresses the pressing need to synthesise high-level evidence for lifestyle-based behavioural and/or self-management interventions to reduce risk in stroke secondary prevention in a structured, consistent way.

METHODS

Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria were applied to meta-analyses, demonstrating statistically significant effect sizes to establish the certainty of existing evidence. Electronic databases MEDLINE, Embase, Epistemonikos, and the Cochrane Library of Systematic Reviews were systematically searched, current to March 2023.

RESULTS

Fifteen SRs were identified following screening, with moderate overlap of primary studies demonstrated (5.84% degree of corrected covered area). Interventions identified could be broadly categorised as multimodal; behavioural change; self-management; psychological talk therapies, albeit with overlap between some theoretical domains. Seventy-two meta-analyses addressing twenty-one preventive outcomes of interest were reported. Best-evidence synthesis identifies that for primary outcomes of mortality and future cardiovascular events post-stroke, moderate certainty GRADE evidence supports multimodal interventions to reduce cardiac events, with no available evidence for outcomes of mortality (all-cause or cardiovascular) or recurrent stroke events. For secondary outcomes addressing risk-reducing behaviours, best-evidence synthesis identifies moderate certainty GRADE evidence for multimodal lifestyle-based interventions to increase physical activity participation, and low certainty GRADE evidence for behavioural change interventions to improve healthy eating post-stroke. Similarly, low certainty GRADE evidence supports self-management interventions to improve preventive medication adherence. For mood self-management post-stroke, moderate GRADE evidence supports psychological therapies for remission and/or reduction of depression and low/very low certainty GRADE evidence for reduction of psychological distress and anxiety. Best-evidence for outcomes addressing proxy physiological measures identified low GRADE evidence supporting multimodal interventions to improve blood pressure, waist circumference, and LDL cholesterol.

CONCLUSION

Effective strategies to redress risk-related health behaviours are required in stroke survivors to complement current pharmacological secondary prevention. Inclusion of multimodal interventions and psychological talk therapies in evidence-based stroke secondary prevention programmes is warranted given the moderate GRADE of evidence that supports their role in risk reduction. Given the overlap in primary studies across reviews, often with overlapping theoretical domains between broad intervention categories, further research is required to identify optimal intervention behavioural change theories and techniques employed in behavioural/self-management interventions.

Spatial-temporal analysis of cerebral infarction mortality in Hokkaido, Japan: an ecological study using a conditional autoregressive model

BACKGROUND

Accessibility to stroke treatments is a challenge that depends on the place of residence. However, recent advances in medical technology have improved health outcomes. Nevertheless, the geographic heterogeneity of medical resources may increase regional disparities. Therefore, evaluating spatial and temporal influences of the medical system on regional outcomes and advanced treatment of cerebral infarction are important from a health policy perspective. This spatial and temporal study aims to identify factors associated with mortality and to clarify regional disparities in cerebral infarction mortality at municipality level.

METHODS

This ecological study used public data between 2010 and 2020 from municipalities in Hokkaido, Japan. We applied spatial and temporal condition autoregression analysis in a Bayesian setting, with inference based on the Markov chain Monte Carlo simulation. The response variable was the number of deaths due to cerebral infarction (ICD-10 code: I63). The explanatory variables were healthcare accessibility and socioeconomic status.

RESULTS

The large number of emergency hospitals per 10,000 people (relative risk (RR) = 0.906, credible interval (Cr) = 0.861 to 0.954) was associated with low mortality. On the other hand, the large number of general hospitals per 10,000 people (RR = 1.123, Cr = 1.068 to 1.178) and longer distance to primary stroke centers (RR = 1.064, Cr = 1.014 to 1.110) were associated with high mortality. The standardized mortality ratio decreased from 2010 to 2020 in Hokkaido by approximately 44%. Regional disparity in mortality remained at the same level from 2010 to 2015, after which it narrowed by approximately 5% to 2020. After mapping, we identified municipalities with high mortality rates that emerged in Hokkaido's central and northeastern parts.

CONCLUSION

Cerebral infarction mortality rates and the disparity in Hokkaido improved during the study period (2010-2020). This study emphasized that healthcare accessibility through places such as emergency hospitals and primary stroke centers was important in determining cerebral infarction mortality at the municipality level. In addition, this study identified municipalities with high mortality rates that require healthcare policy changes. The impact of socioeconomic factors on stroke is a global challenge, and improving access to healthcare may reduce disparities in outcomes.