Health Care Encounters Prior to Hospitalization for Cerebral Venous Thrombosis Patients.

BACKGROUND: Unlike other causes of stroke, symptoms in cerebral venous thrombosis (CVT) can be nonspecific at onset with gradual worsening over time. To explore potential opportunities for earlier diagnosis, we analyzed healthcare interactions in the week prior to hospitalization for patients admitted with incident CVT in British Columbia (BC). METHODS: We constructed a population-based cohort (2000-2017) using linked patient-level administrative data to identify patients aged ≥18 diagnosed with CVT in BC. We used descriptive analysis to describe the frequency and types of healthcare encounters within the 7 and 3 days prior to hospitalization. Multivariable logistic regression modeling was performed to examine risk factors associated with prior encounters. RESULTS: The cohort included 554 patients (mean age 50.9 years, 55.4% female). Within the 7 days prior to CVT hospitalization, 57.9% of patients had ≥1 outpatient encounter and 5.6% had ≥1 inpatient encounter. In the 3 days prior to hospitalization, 46.8% of patients had ≥1 outpatient encounter and 2.0% had ≥1 inpatient encounter. Women more frequently had outpatient interactions within 7 days (64.8% women vs. 35.2% men, p < 0.001) and 3 days (51.8% vs. 48.2%, p = 0.01) before admission. Common provider specialties for outpatient encounters were general practice (58.0%), emergency (8.3%) and neurology (5.7%). Females had higher odds (OR = 1.79) of having ≥1 outpatient encounter after adjusting for confounding. CONCLUSIONS: Within our Canadian cohort, over half of patients had a healthcare encounter within 7 days before their hospitalization with incident CVT. Women more commonly had an outpatient encounter preceding hospital admission.

Trends in cerebral venous thrombosis before and during the COVID-19 pandemic: Analysis of the National Inpatient Sample.

OBJECTIVES: We sought to provide updated incidence and trend data for cerebral venous thrombosis (CVT) in the United States from 2016-2020, examine the impact of the COVID-19 pandemic on CVT, and identify predictors of in-hospital mortality. MATERIALS AND METHODS: Validated ICD-10 codes were used to identify discharges with CVT in the National Inpatient Sample (NIS). Sample weights were applied to generate nationally representative estimates, and census data were used to compute incidence rates. The first wave of the COVID-19 pandemic was defined as January-May 2020. Trend analysis was completed using Joinpoint regression. RESULTS: From 2016 to 2020, the incidence of CVT increased from 24.34 per 1,000,000 population per year (MPY) to 33.63 per MPY (Annual Percentage Change (APC) 8.6 %; p < 0.001). All-cause in-hospital mortality was 4.9 % [95 % CI 4.5-5.4]. On multivariable analysis, use of thrombectomy, increased age, atrial fibrillation, stroke diagnosis, infection, presence of prothrombotic hematologic conditions, lowest quartile of income, intracranial hemorrhage, and male sex were associated with in-hospital mortality. CVT incidence was similar comparing the first 5 months of 2020 and 2019 (31.37 vs 32.04; p = 0.322) with no difference in median NIHSS (2 [IQR 1-10] vs. 2 [1-9]; p = 0.959) or mortality (4.2 % vs. 5.6 %; p = 0.176). CONCLUSIONS: CVT incidence increased in the US from 2016 to 2020 while mortality did not change. Increased age, prothrombotic state, stroke diagnosis, infection, atrial fibrillation, male sex, lowest quartile of income, intracranial hemorrhage, and use of thrombectomy were associated with in-hospital mortality following CVT. During the first wave of the COVID-19 pandemic, CVT volumes and mortality were similar to the prior year.

Antithrombotic Treatment for Stroke Prevention in Cervical Artery Dissection: The STOP-CAD Study.

BACKGROUND: Small, randomized trials of patients with cervical artery dissection showed conflicting results regarding optimal stroke prevention strategies. We aimed to compare outcomes in patients with cervical artery dissection treated with antiplatelets versus anticoagulation. METHODS: This is a multicenter observational retrospective international study (16 countries, 63 sites) that included patients with cervical artery dissection without major trauma. The exposure was antithrombotic treatment type (anticoagulation versus antiplatelets), and outcomes were subsequent ischemic stroke and major hemorrhage (intracranial or extracranial hemorrhage). We used adjusted Cox regression with inverse probability of treatment weighting to determine associations between anticoagulation and study outcomes within 30 and 180 days. The main analysis used an as-treated crossover approach and only included outcomes occurring with the above treatments. RESULTS: The study included 3636 patients (402 [11.1%] received exclusively anticoagulation and 2453 [67.5%] received exclusively antiplatelets). By day 180, there were 162 new ischemic strokes (4.4%) and 28 major hemorrhages (0.8%); 87.0% of ischemic strokes occurred by day 30. In adjusted Cox regression with inverse probability of treatment weighting, compared with antiplatelet therapy, anticoagulation was associated with a nonsignificantly lower risk of subsequent ischemic stroke by day 30 (adjusted hazard ratio [HR], 0.71 [95% CI, 0.45-1.12]; P=0.145) and by day 180 (adjusted HR, 0.80 [95% CI, 0.28-2.24]; P=0.670). Anticoagulation therapy was not associated with a higher risk of major hemorrhage by day 30 (adjusted HR, 1.39 [95% CI, 0.35-5.45]; P=0.637) but was by day 180 (adjusted HR, 5.56 [95% CI, 1.53-20.13]; P=0.009). In interaction analyses, patients with occlusive dissection had significantly lower ischemic stroke risk with anticoagulation (adjusted HR, 0.40 [95% CI, 0.18-0.88]; Pinteraction=0.009). CONCLUSIONS: Our study does not rule out the benefit of anticoagulation in reducing ischemic stroke risk, particularly in patients with occlusive dissection. If anticoagulation is chosen, it seems reasonable to switch to antiplatelet therapy before 180 days to lower the risk of major bleeding. Large prospective studies are needed to validate our findings.

Endovascular Treatment of Acute Ischemic Stroke After Cardiac Interventions in the United States.

Importance: Ischemic stroke is a serious complication of cardiac intervention, including surgery and percutaneous procedures. Endovascular thrombectomy (EVT) is an effective treatment for ischemic stroke and may be particularly important for cardiac intervention patients who often cannot receive intravenous thrombolysis. Objective: To examine trends in EVT for ischemic stroke during hospitalization of patients with cardiac interventions vs those without in the United States. Design, Setting, and Participants: This cohort study involved a retrospective analysis using data for 4888 US hospitals from the 2016-2020 National Inpatient Sample database. Participants included adults (age ≥18 years) with ischemic stroke (per codes from the International Statistical Classification of Diseases, Tenth Revision, Clinical Modification), who were organized into study groups of hospitalized patients with cardiac interventions vs without. Individuals were excluded from the study if they had either procedure prior to admission, EVT prior to cardiac intervention, EVT more than 3 days after admission or cardiac intervention, or endocarditis. Data were analyzed from April 2023 to October 2023. Exposures: Cardiac intervention during admission. Main Outcomes and Measures: The odds of undergoing EVT by cardiac intervention status were calculated using multivariable logistic regression. Adjustments were made for stroke severity in the subgroup of patients who had a National Institutes of Health Stroke Scale (NIHSS) score documented. As a secondary outcome, the odds of discharge home by EVT status after cardiac intervention were modeled. Results: Among 634 407 hospitalizations, the mean (SD) age of the patients was 69.8 (14.1) years, 318 363 patients (50.2%) were male, and 316 044 (49.8%) were female. A total of 12 093 had a cardiac intervention. An NIHSS score was reported in 218 576 admissions, 216 035 (34.7%) without cardiac intervention and 2541 (21.0%) with cardiac intervention (P < .001). EVT was performed in 23 660 patients (3.8%) without cardiac intervention vs 194 (1.6%) of those with cardiac intervention (P < .001). After adjustment for potential confounders, EVT was less likely to be performed in stroke patients with cardiac intervention vs those without (adjusted odds ratio [aOR], 0.27; 95% CI, 0.23-0.31), which remained consistent after adjusting for NIHSS score (aOR, 0.28; 95% CI, 0.22-0.35). Among individuals with a cardiac intervention, receiving EVT was associated with a 2-fold higher chance of discharge home (aOR, 2.21; 95% CI, 1.14-4.29). Conclusions and Relevance: In this study, patients hospitalized with ischemic stroke and cardiac intervention may be less than half as likely to receive EVT as those without cardiac intervention. Given the known benefit of EVT, there is a need to better understand the reasons for lower rates of EVT in this patient population.

Prognosis after cerebral venous thrombosis: Mortality during initial admission and at 30 days and one year after discharge in a large Canadian population-based cohort.

BACKGROUND: Prognosis following cerebral venous thrombosis (CVT) is more favorable than other stroke types, but longer-term literature is limited, and trends over time are under-explored. OBJECTIVE: Using administrative data, we examined factors associated with mortality in the inpatient setting, at 30 days and at one year following hospital discharge among a large consecutive cohort of Canadian patients with CVT. DESIGN/METHODS: CVT patients from British Columbia (BC), Canada from 2000 to 2017 were identified using ICD diagnosis codes from the BC subset of the Canadian Institute for Health Information's Discharge Abstract Database. Logistic regression was used to investigate factors associated with inpatient mortality and survival analysis with Cox regression was used to explore factors associated with mortality at 30 days and one year. RESULTS: Of 554 incident CVT patients identified, 508 (92 %) survived their index admission. Older age (OR 1.04, 95 % CI 1.03-1.06, p < 0.01) and the presence of seizures (OR 2.31, 95 % CI 1.08-4.94, p = 0.03) or intracranial bleeding (OR 2.28, 95 % CI 1.08-4.85, p = 0.03) were associated with increased odds of inpatient mortality. Mortality after hospital discharge was 3.0 % at 30 days and 9.4 % at one year. Older age (HR 1.05, 95 % CI 1.02-1.08, p < 0.01 at 30 days; HR 1.05, 95 % CI 1.04-1.07, p < 0.01 at 1 year) and having recent or active malignancy (HR 4.17, 95 % CI 1.51-11.52, p < 0.01 at 30 days; HR 4.60, 95 % CI 2.60-8.11, p < 0.01 at 1 year) were significantly associated with higher risks of mortality at 30 days and one year after discharge. There were decreases in inpatient mortality over the study period, but this was offset by higher mortality within 30 days after discharge in the later study epochs. CONCLUSIONS: Among patients discharged with a diagnosis of CVT, one-year mortality was high at 9.4 %. Older age and a history of cancer were associated with higher mortality after discharge.

Rates and reasons for hospital readmission after acute ischemic stroke in a US population-based cohort.

Hospital readmissions following stroke are costly and lead to worsened patient outcomes. We examined readmissions rates, diagnoses at readmission, and risk factors associated with readmission following acute ischemic stroke (AIS) in a large United States (US) administrative database. Using the 2019 Nationwide Readmissions Database, we identified adults discharged with AIS (ICD-10-CM I63*) as the principal diagnosis. Survival analysis with Weibull accelerated failure time regression was used to examine variables associated with hospital readmission. In 2019, 273,811 of 285,451 AIS patients survived their initial hospitalization. Of these, 60,831 (22.2%) were readmitted within 2019. Based on Kaplan Meyer analysis, readmission rates were 9.7% within 30 days and 30.5% at 1 year following initial discharge. The most common causes of readmissions were stroke and post stroke sequalae (25.4% of 30-day readmissions, 15.0% of readmissions between 30-364 days), followed by sepsis (10.3% of 30-day readmissions, 9.4% of readmissions between 30-364 days), and acute renal failure (3.2% of 30-day readmissions, 3.0% of readmissions between 30-364 days). After adjusting for multiple patient and hospital-level characteristics, patients at increased risk of readmission were older (71.6 vs. 69.8 years, p<0.001) and had longer initial lengths of stay (7.6 vs. 6.2 day, p<0.001). They more often had modifiable comorbidities, including vascular risk factors (hypertension, diabetes, atrial fibrillation), depression, epilepsy, and drug abuse. Social determinants associated with increased readmission included living in an urban (vs. rural) setting, living in zip-codes with the lowest median income, and having Medicare insurance. All factors were significant at p<0.001. Unplanned hospital readmissions following AIS were high, with the most common reasons for readmission being recurrent stroke and post stroke sequalae, followed by sepsis and acute renal failure. These findings suggest that efforts to reduce readmissions should focus on optimizing secondary stroke and infection prevention, particularly among older socially disadvantaged patients.

Recanalization and outcomes after cerebral venous thrombosis: a systematic review and meta-analysis.

Background: Recanalization in cerebral venous thrombosis (CVT) can begin as early as 1 week after initiating therapeutic anticoagulation. The clinical significance of recanalization remains uncertain. Objectives: We aimed to investigate the association between recanalization and functional outcomes and explored predictors of recanalization. Methods: A systematic literature search was conducted (EMBASE, MEDLINE, Cochrane library) to identify: (1) patients with CVT aged ≥18 years treated with anticoagulation only; (2) case series, cohort, or randomized controlled trial studies; and (3) reported recanalization rates and functional outcomes using either a modified Rankin Scale (mRS) or sequelae of CVT at last follow-up. Meta-analysis was performed using pooled odds ratios (ORs) with exploration of sex and age effects using meta-regression. Results: Twenty-three studies were eligible with 1418 individual patients in total. Timing of reimaging and clinical reassessment was variable. Absence of recanalization was associated with increased odds of an unfavorable functional outcome (mRS 2-6 versus 0-1; OR, 3.66; 95% CI, 1.73-7.74; p = 0.001), CVT recurrence (OR, 8.81; 95% CI, 1.63-47.7; p = 0.01), and chronic headache (OR, 2.78; 95% CI, 1.16-6.70; p = 0.02). On meta-regression, the relationship between recanalization and mRS differed by the proportion of female patients, where lower proportions of women were associated with higher likelihood of a worse outcome, but not by mean participant age. There was no incremental benefit of full compared with partial recanalization with respect to favorable mRS or recurrence, but odds of chronic headache were higher with partial versus full recanalization (OR, 3.80; 95% CI, 1.43-10.11; p = 0.008). Epilepsy and visual sequelae were not associated with recanalization. Conclusions: Absence of recanalization was associated with worse functional outcomes, CVT recurrence, and headache, but outcomes were modified by sex. The degree of recanalization was significant in relation to headache outcomes, where partial compared with complete recanalization resulted in a greater likelihood of residual headache. Prospective studies with common timing of repeat clinical-neuroimaging assessments will help to better ascertain the relationship and directionality between the degree of recanalization and outcomes.

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.

Effect of COVID-19 on Acute Ischemic Stroke Severity and Mortality in 2020: Results From the 2020 National Inpatient Sample.

BACKGROUND: There is a paucity of nationally representative data regarding the impact of COVID-19 on acute ischemic stroke (AIS) outcome. METHODS: We created a cross-sectional cohort of nationally weighted National Inpatient Sample nonelective hospital discharges aged ≥18 years with a diagnosis of ischemic stroke from 2016 to 2020. The outcome was in-hospital mortality and exposure was COVID-19 status. To understand the effect of COVID-19 on AIS severity, we report National Institutes of Health Stroke Scale by exposure status. In a final analysis, we used a nationally weighted logistic regression and marginal effects to compare April to December 2020 to the same period in 2019 to understand how the pandemic modified the effect of race and ethnicity and median household income on in-hospital AIS mortality. RESULTS: We observed significantly higher AIS mortality in 2020 than prior years (2020 versus 2016-19, 7.3% versus 6.3%, P<0.001) and higher National Institutes of Health Stroke Scale in those with COVID-19 than those without (mean: 9.7±9.1 versus 6.6±7.4, P<0.001), but patients with AIS without COVID in 2020 had only marginally higher mortality (2020 versus 2016-2019, 6.6% versus 6.3%, P=0.001). Comparing April to December 2020 to 2019, the adjusted risk of in-hospital AIS mortality was most notably increased in Hispanics (2020 versus 2019: 9.2% versus 5.8%, P<0.001) and the lowest quartile of income (2020 versus 2019: 8.0% versus 6.0%, P<0.001). CONCLUSIONS: In-hospital stroke mortality increased in 2020 in the United States because of comorbid AIS and COVID-19, which had higher stroke severity. The increase in AIS mortality during April-December 2020 was significantly more pronounced in Hispanics and those in the lowest quartile of household income.

Embolic Stroke of Undetermined Source: Current Perspectives on Diagnosis, Investigations, and Management.

In 2014, Hart et al. introduced the concept of "embolic stroke of undetermined source" (ESUS) to the clinical-research stroke community. The hypothesis underlying the development of the ESUS construct was that this potentially heterogenous group of stroke mechanisms were largely thromboembolic, and would thus benefit from anticoagulation over antiplatelet for secondary prevention. Since then, 2 large clinical trials have shown that, to date, there is not a clear uniform antithrombotic strategy for secondary prevention after ESUS as it was originally broadly defined. However, this work has yielded valuable information about the patient phenotypes that experience ESUS strokes, as well as hypothesis-generating substudies that have given rise to the next generation of secondary prevention trials aimed at more personalized approaches for different suspected mechanisms of embolic stroke. In parallel with the evolution of ESUS, several studies aimed at screening for atrial fibrillation in the secondary stroke prevention population have generated additional questions about the mechanistic relevance of atrial fibrillation detected after stroke, and how this should inform poststroke workup, and secondary prevention strategies. Herein, we provide a synthesis of the current understanding surrounding the patient phenotypes that experience ESUS strokes, and previous, ongoing, and anticipated clinical trials that will guide earlier and later secondary prevention strategies and poststroke cardiac investigations.

Incidence of Cerebral Venous Thrombosis: A Population-Based Study, Systematic Review, and Meta-Analysis.

BACKGROUND: Studying the baseline incidence of cerebral venous thrombosis (CVT) prior to COVID-19 and the limitations of how this has been previously reported in the literature will help improve understanding of this disease and how risks may have changed in the post-COVID era. METHODS: We examined CVT incidence using linked administrative data in British Columbia, Canada (population 5.2 million). To contextualize our findings, we also examined CVT incidence in the published literature and searched MEDLINE and EMBASE for article titles and abstracts up to Nov 2, 2021 on CVT incidence in adults. We performed abstract screening and full-text review prior to data extraction and explored associations between CVT incidence and year of study, geographic location, and study quality with meta-analyses and meta-regression. A random-effects restricted maximum likelihood model was used. Publication bias was assessed using the Egger tests and using visual inspection of the funnel plot for symmetry. RESULTS: There were 554 unique CVT cases (mean age 50.9 years, 55.4% women) in British Columbia from 2000 to 2017; overall annual incidence was 8.7 (95%CI' 8.0-9.4) per million. Incidence increased over time in men across the entire study period, and from 2011 to 2017 in women. We identified 22 other studies on CVT incidence before 2020 (21/23 total studies included in meta-analysis). Annual incidence overall was 12.1 (95% CI' 9.9-14.3) per million with significant between-study heterogeneity (I2 98.8%, Qp-value<0.001). There were no significant associations on meta-regression between incidence and study year, study quality score, or gross national income per capita of the study country. Visual inspection of the funnel plot and a significant Egger test (z=2.8, P<0.01) suggested possible publication bias. CONCLUSIONS: Incidence of CVT in Canadian data increased over time but remained lower than in other population-based studies. Significant heterogeneity exists in the literature, which may be subject to publication bias.

Quantifying Improved Outcomes, Cost Savings, and Hospital Volume Changes From Optimized Emergency Stroke Transport.

BACKGROUND: A previously published conditional probability model optimizes prehospital emergency transport protocols for patients with suspected large-vessel occlusion by recommending the transport strategy, drip-and-ship or mothership, that results in a higher probability of an excellent outcome. In this study, we create generalized models to quantify the change in annual hospital patient volume, the expected annual increase in the number of patients with an excellent outcome, and the annual cost savings to a single-payer healthcare system resulting from these optimized transport protocols. METHODS: We calculated the expected number of patients with suspected large-vessel occlusion transported by ambulance over a 1-year period in a region of interest, using the annual stroke incidence rate and a large-vessel occlusion screening tool. Assuming transport to the closest hospital is the baseline transport policy across the region (drip-and-ship), we determined the change in annual hospital patient volume from implementing optimized transport protocols. We also calculated the resulting annual increase in the number of patients with an excellent outcome (modified Rankin Score of 0-1 at 90 days) and associated cost savings to a single-payer healthcare system. We then performed a case study applying these generalized models to the stroke system serving the Greater Vancouver and Fraser Valley Area, BC, Canada. RESULTS: In the Greater Vancouver and Fraser Valley Area, there was an annual increase of 36 patients with an excellent outcome, translating to an annual cost savings of CA$2 182 824 to the British Columbia healthcare system. We also studied how these results change depending on our assumptions of treatment times at the regional stroke centers. CONCLUSIONS: Our framework quantifies the impact of optimized emergency stroke transport protocols on hospital volume, outcomes, and cost savings to a single-payer healthcare system. When applied to a specific region of interest, these models can help inform health policies concerning emergency transport of patients with suspected large-vessel occlusion.

Cost-Effectiveness of Cilostazol Added to Aspirin or Clopidogrel for Secondary Prevention After Noncardioembolic Stroke.

Background The objective of the study was to assess the cost-effectiveness of cilostazol (a selective phosphodiesterase 3 inhibitor) added to aspirin or clopidogrel for secondary stroke prevention in patients with noncardioembolic stroke. Methods and Results A Markov model decision tree was used to examine lifetime costs and quality-adjusted life years (QALYs) of patients with noncardioembolic stroke treated with either aspirin or clopidogrel or with additional cilostazol 100 mg twice daily. Cohorts were followed until all patients died from competing risks or ischemic or hemorrhagic stroke. Probabilistic sensitivity analysis using Monte Carlo simulation was used to model 10 000 cohorts of 10 000 patients. The addition of cilostazol to aspirin or clopidogrel is strongly cost saving. In all 10 000 simulations, the cilostazol strategy resulted in lower health care costs compared with aspirin or clopidogrel alone (mean $13 488 cost savings per patient; SD, $8087) and resulted in higher QALYs (mean, 0.585 more QALYs per patient lifetime; SD, 0.290). This result remained robust across a variety of sensitivity analyses, varying cost inputs, and treatment effects. At a willingness-to-pay threshold of $50 000/QALY, average net monetary benefit from the addition of cilostazol was $42 743 per patient over their lifetime. Conclusions Based on the best available data, the addition of cilostazol to aspirin or clopidogrel for secondary prevention following noncardioembolic stroke results in significantly reduced health care costs and a gain in lifetime QALYs.

Validity of ICD-10 Codes for Cerebral Venous Thrombosis Depends on Clinical Context.

We examined the accuracy of International Classification of Disease 10th iteration (ICD-10) diagnosis codes within Canadian administrative data in identifying cerebral venous thrombosis (CVT). Of 289 confirmed cases of CVT admitted to our comprehensive stroke center between 2008 and 2018, 239/289 were new diagnoses and 204/239 were acute events with only 75/204 representing symptomatic CVTs not provoked by trauma or structural processes. Using ICD-10 codes in any position, sensitivity was 39.1% and positive predictive value was 94.2% for patients with a current or history of CVT and 84.0% and 52.5% for acute and symptomatic CVTs not provoked by trauma or structural processes.

Background incidence rates of hospitalisations and emergency department visits for thromboembolic and coagulation disorders in Ontario, Canada for COVID-19 vaccine safety assessment: a population-based retrospective observational study.

OBJECTIVE: The objective of this study was to estimate background rates of selected thromboembolic and coagulation disorders in Ontario, Canada. DESIGN: Population-based retrospective observational study using linked health administrative databases. Records of hospitalisations and emergency department visits were searched to identify cases using International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Canada diagnostic codes. PARTICIPANTS: All Ontario residents. PRIMARY OUTCOME MEASURES: Incidence rates of ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, deep vein thrombosis, pulmonary embolism, idiopathic thrombocytopaenia, disseminated intravascular coagulation and cerebral venous thrombosis during five prepandemic years (2015-2019) and 2020. RESULTS: The average annual population was 14 million with 51% female. The mean annual rates per 100 000 population during 2015-2019 were 127.1 (95% CI 126.2 to 127.9) for ischaemic stroke, 22.0 (95% CI 21.6 to 22.3) for intracerebral haemorrhage, 9.4 (95% CI 9.2 to 9.7) for subarachnoid haemorrhage, 86.8 (95% CI 86.1 to 87.5) for deep vein thrombosis, 63.7 (95% CI 63.1 to 64.3) for pulmonary embolism, 6.1 (95% CI 5.9 to 6.3) for idiopathic thrombocytopaenia, 1.6 (95% CI 1.5 to 1.7) for disseminated intravascular coagulation, and 1.5 (95% CI 1.4 to 1.6) for cerebral venous thrombosis. Rates were lower in 2020 than during the prepandemic years for ischaemic stroke, deep vein thrombosis and idiopathic thrombocytopaenia. Rates were generally consistent over time, except for pulmonary embolism, which increased from 57.1 to 68.5 per 100 000 between 2015 and 2019. Rates were higher for females than males for subarachnoid haemorrhage, pulmonary embolism and cerebral venous thrombosis, and vice versa for ischaemic stroke and intracerebral haemorrhage. Rates increased with age for most of these conditions, but idiopathic thrombocytopaenia demonstrated a bimodal distribution with incidence peaks at 0-19 years and ≥60 years. CONCLUSIONS: Our estimated background rates help contextualise observed events of these potential adverse events of special interest and to detect potential safety signals related to COVID-19 vaccines.

Capturing Intravenous Thrombolysis for Acute Stroke at the ICD-9 to ICD-10 Transition: Case Volume Discontinuity in the United States National Inpatient Sample.

Background Transition from International Classification of Diseases (ICD) Ninth and Tenth Revisions (ICD-9 and ICD-10) for hospital discharge data was mandated for US hospitals on October 1, 2015. We examined the volume of patients receiving thrombolysis in ischemic stroke (IS) identified using ICD codes within this transition period in the 2015 to 2016 National Inpatient Sample, a weighted 20% sample of all inpatient US hospital discharges. Methods and Results During the ICD-10 period, 2 case identification strategies were used. Codes for IS were combined with: (1) only the ICD-10 code for thrombolytic given into a peripheral vein and (2) all new ICD-10 codes mapped to the ICD-9 code for all thrombolysis. On visual inspection there was an obvious discontinuity in the volume of patients with IS treated with IV thrombolysis corresponding to 3 time periods: ICD-9 (study period 1), transition (period 2), and ICD-10 (period 3). With Strategy 1, analysis using a linear spline with 2 knots shows that the volume of patients with IS treated with IV thrombolysis was significantly different between study periods 1 and 2 (slope difference -1880, 95% CI -2834 to -928, P=0.005), and periods 2 to 3 (slope difference 1980, 95% CI 1207-2754, P = 0.002). With Strategy 2, volumes did not change significantly between periods 1 to 2, though there was a significant difference between periods 2 and 3 (slope difference 719, 95% CI 91-1347, P=0.034). Conclusions The significant discontinuity in thrombolysis volumes for IS during the transition period for ICD-9 to ICD-10 coding suggests that more rigorous validation of US administrative data during this time period may be necessary for research, resource planning, and quality assurance.