scholarly journals Socioeconomic status and survival after stroke – using mediation and sensitivity analyses to assess the effect of stroke severity and unmeasured confounding

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Anita Lindmark ◽  
Bo Norrving ◽  
Marie Eriksson

Abstract Background Although it has been established that low socioeconomic status is linked to increased risk of death after stroke, the mechanisms behind this link are still unclear. In this study we aim to shed light on the relationship between income level and survival after stroke by investigating the extent to which differences in stroke severity account for differences in survival. Methods The study was based on patients registered in Riksstroke (the Swedish stroke register) with first time ischemic stroke (n = 51,159) or intracerebral hemorrhage (n = 6777) in 2009–2012. We used causal mediation analysis to decompose the effect of low income on 3-month case fatality into a direct effect and an indirect effect due to stroke severity. Since causal mediation analysis relies on strong assumptions regarding residual confounding of the relationships involved, recently developed methods for sensitivity analysis were used to assess the robustness of the results to unobserved confounding. Results After adjustment for observed confounders, patients in the lowest income tertile had a 3.2% (95% CI: 0.9–5.4%) increased absolute risk of 3-month case fatality after intracerebral hemorrhage compared to patients in the two highest tertiles. The corresponding increase for case fatality after ischemic stroke was 1% (0.4–1.5%). The indirect effect of low income, mediated by stroke severity, was 1.8% (0.7–2.9%) for intracerebral hemorrhage and 0.4% (0.2–0.6%) for ischemic stroke. Unobserved confounders affecting the risk of low income, more severe stroke and case fatality in the same directions could explain the indirect effect, but additional adjustment to observed confounders did not alter the conclusions. Conclusions This study provides evidence that as much as half of income-related inequalities in stroke case fatality is mediated through differences in stroke severity. Targeting stroke severity could therefore lead to a substantial reduction in inequalities and should be prioritized. Sensitivity analysis suggests that additional adjustment for a confounder of greater impact than age would be required to considerably alter our conclusions.

KYAMC Journal ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 8-12
Author(s):  
Achinta Kumar Mallick ◽  
Md Ahmed Ali ◽  
Md Kafiluddin ◽  
Md Parvez Amin ◽  
Pijus Kumar Kundu ◽  
...  

Background: Atrial fibrillation (AF) is a common arrhythmia and a major risk factor for ischemic stroke, especially in the elderly patients. Patients with non-valvular AF have a 5-fold excess risk of stroke recurrence and case-fatality rate.Objectives: This study was to evaluate the prevalence of AF and its influence on prognosis in patients with ischemic stroke.Materials & Methods: Total 125 patients with ischaemic stroke were enrolled in this study. Initially they were divided into two groups by ECG - those with AF and those without AF. They were followed up after one month, three months and six months. Comparison was done between the two groups in term of recurrence, mortality and clinical improvement which were assessed by Modified Rankin Score (MRS).Results: Among 125 patients, 22 patients had AF. Those with AF were more frequently male, aged more than 45 years. Recurrence was significantly higher in AF group during one month follow up (p<0.05). The presence of AF was associated with higher mortality in 3 months (p<0.05) and 6 months (p<0.05) follow up. At 3 months follow up clinical deterioration was noted in 9.1% patient with AF compared to 2.9% patients without AF (p<0.01) and at 6 months follow up clinical deterioration was noted in 18.2% patient with AF compared to 4.9% patients without AF (p<0.01).Conclusion: Patients who had an ischemic stroke with accompanying AF had higher mortality, graver stroke severity, more recurrences and poorer functional status than those without AF.KYAMC Journal Vol. 8, No.-2, Jan 2018, Page 8-12


2017 ◽  
Vol 13 (5) ◽  
pp. 503-510 ◽  
Author(s):  
Raed A Joundi ◽  
Rosemary Martino ◽  
Gustavo Saposnik ◽  
Vasily Giannakeas ◽  
Jiming Fang ◽  
...  

Background Dysphagia screening is recommended after acute stroke to identify patients at risk of aspiration and implement appropriate care. However, little is known about the frequency and outcomes of patients undergoing dysphagia screening after intracerebral hemorrhage (ICH). Methods We used the Ontario Stroke Registry from 1 April 2010 to 31 March 2013 to identify patients hospitalized with acute stroke and to compare dysphagia screening rates in those with ICH and ischemic stroke. In patients with ICH we assessed predictors of receiving dysphagia screening, predictors of failing screening, and outcomes after failing screening. Results Among 1091 eligible patients with ICH, 354 (32.4%) patients did not have documented dysphagia screening. Patients with mild ICH were less likely to receive screening (40.4% of patients were omitted, adjusted odds ratio (aOR) 0.40, 95% confidence interval (CI) 0.26–0.63). Older age, greater stroke severity, speech deficits, lower initial level of consciousness, and admission to intensive care unit were predictive of failing the screening test. Failing screening was associated with poor outcomes, including pneumonia (aOR 5.3, 95% CI 2.36–11.88), severe disability (aOR 4.78, 95% CI 3.08–7.41), and 1-year mortality (adjusted hazard ratio 2.1, 95% CI 1.38–3.17). When compared to patients with ischemic stroke, patients with ICH were less likely to receive dysphagia screening (aOR 0.64, 95% CI 0.54–0.76) and more likely to fail screening (aOR 1.98, 95% 1.62–2.42). Conclusion One-third of patients with ICH did not have documented dysphagia screening, increasing to 40% in patients with mild clinical severity. Failing screening was associated with poor outcomes. Patients with ICH were less like to receive screening and twice as likely to fail compared to patients with ischemic stroke, and thus efforts should be made to include ICH patients in dysphagia screening protocols whenever possible.


2017 ◽  
Vol 28 (2) ◽  
pp. 515-531 ◽  
Author(s):  
Lawrence C McCandless ◽  
Julian M Somers

Causal mediation analysis techniques enable investigators to examine whether the effect of the exposure on an outcome is mediated by some intermediate variable. Motivated by a data example from epidemiology, we consider estimation of natural direct and indirect effects on a survival outcome. An important concern is bias from confounders that may be unmeasured. Estimating natural direct and indirect effects requires an elaborate series of assumptions in order to identify the target quantities. The analyst must carefully measure and adjust for important predictors of the exposure, mediator and outcome. Omitting important confounders may bias the results in a way that is difficult to predict. In recent years, several methods have been proposed to explore sensitivity to unmeasured confounding in mediation analysis. However, many of these methods limit complexity by relying on a handful of sensitivity parameters that are difficult to interpret, or alternatively, by assuming that specific patterns of unmeasured confounding are absent. Instead, we propose a simple Bayesian sensitivity analysis technique that is indexed by four bias parameters. Our method has the unique advantage that it is able to simultaneously assess unmeasured confounding in the mediator–outcome, exposure–outcome and exposure–mediator relationships. It is a natural Bayesian extension of the sensitivity analysis methodologies of VanderWeele, which have been widely used in the epidemiology literature. We present simulation findings, and additionally, we illustrate the method in an epidemiological study of mortality rates in criminal offenders from British Columbia.


Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
M. Carter Denny ◽  
Suhas S Bajgur ◽  
Kim Y Vu ◽  
Rahul R Karamchandani ◽  
Amrou Sarraj ◽  
...  

Introduction: Post-stroke cognitive dysfunction (CD) affects at least 1/3 of acute ischemic stroke (AIS) patients when assessed at 3 months. Limited data exists on CD in intracerebral hemorrhage (ICH). The role of early, in-hospital cognitive screening using the brief Montreal Cognitive Assessment (mini MoCA) is being investigated at our center. Hypothesis: We assessed the rates of early CD in ICH and AIS and hypothesized that even minor deficits from these disorders causes significant CD. Methods: 1218 consecutive stroke patients admitted from 2/13 to 12/13 were reviewed; 610, 442 with AIS and 168 with ICH, with admission NIHSS and mini MoCAs were included in the final analyses. CD was defined as mini MoCA <9 (max 12). Poor outcome was defined as discharge mRS 4-6. Stroke severity was stratified by NIHSS score of 0-5, 6-10, 11-15, 16-20, 21-42 as in ECASS-I . Chi-squared tests and univariate logistic regression analyses were performed. Results: Baseline characteristics are shown in table 1. AIS and ICH groups were similar with regard to race, gender and stroke severity. ICH patients were younger, had longer stroke service lengths of stay and poorer outcomes than AIS patients (p=0.03, p<0.001, p<0.001). No difference was seen in rates of CD between AIS and ICH patients (60% vs. 57%, p=0.36, OR 1.2 (CI 0.8-1.7)). CD rates ranged from 36% for NIHSS 0-5 to 96% for 21-42 (figure 1). Older patients were twice as likely to have CD (p<0.001, OR 2.2 (CI 1.6 - 3.0)). Patients with CD had five times the odds of having a poor outcome compared to the cognitively intact (p<0.001, OR 5.2 (CI 3.4-7.7)). In univariate logistic regression analyses, age was a significant predictor of CD in AIS, but not in ICH (p= <0.001, p=0.06). Conclusion: Post-stroke CD is common across all severities and occurs at similar rates in AIS and ICH. More than 1/3 of patients with minor deficits (NIHSS 0-5) had CD in the acute hospital setting. Whether early CD is predictive of long term cognitive outcomes deserves further study.


Neurology ◽  
2021 ◽  
pp. 10.1212/WNL.0000000000013118
Author(s):  
Nils Skajaa ◽  
Kasper Adelborg ◽  
Erzsébet Horváth-Puhó ◽  
Kenneth J Rothman ◽  
Victor W. Henderson ◽  
...  

Background and Objectives:To examine risks of stroke recurrence and mortality after first and recurrent stroke.Methods:Using Danish nationwide health registries, we included patients (age ≥18 years) with first-time ischemic stroke (N = 105,397) or intracerebral hemorrhage (N = 13,350) during 2004–2018. Accounting for the competing risk of death, absolute risks of stroke recurrence were computed separately for each stroke subtype and within strata of age groups, sex, stroke severity, body mass index, smoking, alcohol, the Essen stroke risk score, and atrial fibrillation. Mortality risks were computed after first and recurrent stroke.Results:After adjusting for competing risks, the overall 1-year and 10-year risks of recurrence were 4% and 13% following first-time ischemic stroke and 3% and 12% following first-time intracerebral hemorrhage. For ischemic stroke, the risk of recurrence increased with age, was higher for men and following mild than more severe stroke. The most marked differences were across Essen risk scores, for which recurrence risks increased with increasing scores. For intracerebral hemorrhage, risks were similar for both sexes and did not increase with Essen risk score. For ischemic stroke, the 1-year and 10-year risks of all-cause mortality were 17% and 56% after a first-time stroke and 25% and 70% after a recurrent stroke; corresponding estimates for intracerebral hemorrhage were 37% and 70% after a first-time event and 31% and 75% after a recurrent event.Conclusion:The risk of stroke recurrence was substantial following both subtypes, but risks differed markedly among patient subgroups. The risk of mortality was higher after a recurrent than first-time stroke.


Author(s):  
Raed A. Joundi ◽  
Eric E. Smith ◽  
Amy Y. X. Yu ◽  
Mohammed Rashid ◽  
Jiming Fang ◽  
...  

Background Temporal trends in life‐sustaining care after acute stroke are not well characterized. We sought to determine contemporary trends by age and sex in the use of life‐sustaining care after acute ischemic stroke and intracerebral hemorrhage in a large, population‐based cohort. Methods and Results We used linked administrative data to identify all hospitalizations for acute ischemic stroke or intracerebral hemorrhage in the province of Ontario, Canada, from 2003 to 2017. We calculated yearly proportions of intensive care unit admission, mechanical ventilation, percutaneous feeding tube placement, craniotomy/craniectomy, and tracheostomy. We used logistic regression models to evaluate the association of age and sex with life‐sustaining care and determined whether trends persisted after adjustment for baseline factors and estimated stroke severity. There were 137 358 people with acute ischemic stroke or intracerebral hemorrhage hospitalized during the study period. Between 2003 and 2017, there was an increase in the proportion receiving care in the intensive care unit (12.4% to 17.7%) and mechanical ventilation (4.4% to 6.6%). There was a small increase in craniotomy/craniectomy, a decrease in percutaneous feeding tube use, and no change in tracheostomy. Trends were generally consistent across stroke types and persisted after adjustment for comorbid conditions, stroke‐center type, and estimated stroke severity. After adjustment, women and those aged ≥80 years had lower odds of all life‐sustaining care, although the disparities in intensive care unit admission narrowed over time. Conclusions Use of life‐sustaining care after acute stroke increased between 2003 and 2017. Women and those at older ages had lower odds of intensive care, although the differences narrowed over time. Further research is needed to determine the reasons for these findings.


2020 ◽  
Author(s):  
Ming Zou ◽  
Yan Li ◽  
Hui Zhao ◽  
Yan Feng ◽  
Ying Zhang ◽  
...  

Abstract Background: Stroke is a devastating and debilitating disease and is a leading cause of death worldwide, including intracerebral hemorrhage (ICH) and ischemic stroke. Emerging evidence indicates that inflammatory cascades after hemorrhagic or ischemic stroke makes a great contribution to brain damage, mainly are involved in neuronal cell death, blood-brain-barrier (BBB) destruction and development of vasogenic edema. However, the features and direct effect of brain inflammation following stroke is still unknown. Methods: We adopted the ICH model by injection of collagenase and used a mouse model of transient cerebral ischemia and reperfusion. And pertussis toxin was used to create a pro-inflammatory milieu. Neurodeficits, lesion volume, production of reactive oxygen species (ROS) and inflammatory factors, brain-infiltrating leukocytes and blood-brain-barrier (BBB) destruction were assessed in mice model treated with pertussis toxin or vehicle.Results: Adopting collagenase induced intracerebral hemorrhage mouse model, we show that pertussis toxin-induced systemic inflammation exacerbated neurological deficits, enlarged lesion size and brain perihematomal edema after intracerebral hemorrhage. Pertussis toxin promoted leukocyte infiltration and inflammatory cytokine release in the brain. Moreover, the integrity of the BBB was further disrupted after receiving pertussis toxin in ICH mice. Furthermore, we demonstrated that pertussis toxin increased stroke severity and enhanced brain inflammation in middle cerebral artery occlusion (MCAO) mouse model. Conclusion: Our results suggest that pertussis toxin increases inflammatory response that exacerbates brain injury after intracerebral hemorrhage or ischemic stroke in mouse model.


Stroke ◽  
2020 ◽  
Vol 51 (6) ◽  
pp. 1720-1726
Author(s):  
Raed A. Joundi ◽  
Gustavo Saposnik ◽  
Rosemary Martino ◽  
Jiming Fang ◽  
Moira K. Kapral

Background and Purpose— We aimed to create a novel prognostic risk score to estimate outcomes after direct enteral tube placement in acute stroke. Methods— We used the Ontario Stroke Registry and linked databases to obtain clinical information on all patients with direct enteral tube insertion after ischemic stroke or intracerebral hemorrhage from July 1, 2003 to June 30, 2010 (derivation cohort) and July 1, 2010 to March 31, 2013 (validation cohort). We used multivariable regression to assign scores to predictor variables for 3 outcomes after tube placement: favorable outcome (discharge modified Rankin Scale score 0–3 and alive at 90 days), poor outcome (discharge modified Rankin Scale score 5 or death at 90 days), and 30-day mortality. Results— Variables associated with a favorable outcome were younger age, preadmission independence, ischemic stroke rather than intracerebral hemorrhage, lower stroke severity, and a shorter time between stroke and tube placement. Variables associated with a poor outcome were older age, preadmission dependence, atrial fibrillation, greater stroke severity, and tracheostomy. Age, preadmission dependence, atrial fibrillation, cancer, chronic obstructive pulmonary disease, and shorter time to tube placement were associated with increased 30-day mortality. Using these variables, we created an online calculator to facilitate estimation of individual patient risk of favorable and poor outcomes. C -statistic in the validation cohort was 0.82 for favorable outcome, 0.65 for poor outcome, and 0.62 for 30-day mortality, and calibration was adequate. Conclusions— We developed risk scores to estimate outcomes after direct enteral tube insertion for acute dysphagic stroke. This information may be useful in discussions with patients and families when there is prognostic uncertainty surrounding outcomes with direct enteral tube placement after stroke.


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