Accuracy of Administrative Data for the Coding of Acute Stroke and TIAs

Association Between Neighborhood-Level Income and the Incidence of Cardiovascular Events Varies by Immigration Status: A Population-Based Cohort Study

BACKGROUND

Neighborhood-level income is inversely associated with cardiovascular events; however, it is uncertain whether this association varies with immigration status.

METHODS AND RESULTS

We conducted a population-based cohort study of 5.2 million (53% women, 19% immigrants) urban-dwelling people aged ≥40 years without a prior history of cardiovascular disease in Ontario, Canada. Neighborhood-level income was measured in quintiles from quintile 1 (lowest) to quintile 5 (highest), and immigrants were defined as those born outside of Canada who moved to Canada after 1985. We estimated the association between neighborhood-level income and the rate of incident cardiovascular events (hospitalization for stroke or myocardial infarction, or cardiovascular death) using multivariable cause-specific hazards models and added an interaction term to see if the association varies by immigration status. The absolute difference in the rate of cardiovascular events across income quintiles was less pronounced in immigrants than in long-term residents: age- and sex-adjusted rate per 1000 person-years in quintile 1 versus quintile 5: 5.69 versus 4.10 in immigrants and 8.37 versus 5.87 in long-term residents. In adjusted models, the interaction between immigration status and neighborhoodl evel was significant (Pinteraction <0.001). The hazard of cardiovascular events declined with increasing income among long-term residents (hazard ratio [HR]Q1vsQ5, 1.46 to HRQ4vsQ5, 1.10) and immigrants, albeit with a smaller gradient (HRQ1vsQ5, 1.43 to HRQ4vsQ5, 1.20).

CONCLUSIONS

The association between neighborhood-level income and cardiovascular disease incidence varies by immigration status. Understanding the social and structural factors associated with residing in low-income neighborhoods can help with the development of prevention programs that improve health for all.

Derivation and Validation of ICD-10 Codes for Identifying Incident Stroke

Importance

Claims data with International Statistical Classification of Diseases, Tenth Revision (ICD-10) codes are routinely used in clinical research. However, the use of ICD-10 codes to define incident stroke has not been validated against expert-adjudicated outcomes in the US population.

Objective

To develop and validate the accuracy of an ICD-10 code list to detect incident stroke events using Medicare inpatient fee-for-service claims data.

Design, Setting, and Participants

This cohort study used data from 2 prospective population-based cohort studies, the Atherosclerosis Risk in Communities (ARIC) study and the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, and included participants aged 65 years or older without prior stroke who had linked Medicare claims data. Stroke events in the ARIC and REGARDS studies were identified via active surveillance and adjudicated by expert review. Medicare-linked ARIC data (2016-2018) were used to develop a list of ICD-10 codes for incident stroke detection. The list was validated using Medicare-linked REGARDS data (2016-2019). Data were analyzed from September 1, 2022, through September 30, 2023.

Exposures

Stroke events detected in Medicare claims vs expert-adjudicated stroke events in the ARIC and REGARDS studies.

Main Outcomes and Measures

The main outcomes were sensitivity and specificity of incident stroke detection using ICD-10 codes.

Results

In the ARIC study, there were 110 adjudicated incident stroke events among 5194 participants (mean [SD] age, 80.1 [5.3] years) over a median follow-up of 3.0 (range, 0.003-3.0) years. Most ARIC participants were women (3160 [60.8%]); 993 (19.1%) were Black and 4180 (80.5%) were White. Using the primary diagnosis code on a Medicare billing claim, the ICD-10 code list had a sensitivity of 81.8% (95% CI, 73.3%-88.5%) and a specificity of 99.1% (95% CI, 98.8%-99.3%) to detect incident stroke. Using any diagnosis code on a Medicare billing claim, the sensitivity was 94.5% (95% CI, 88.5%-98.0%) and the specificity was 98.4% (95% CI, 98.0%-98.8%). In the REGARDS study, there were 140 adjudicated incident strokes among 6359 participants (mean [SD] age, 75.8 [7.0] years) over a median follow-up of 4.0 (range, 0-4.0) years. More than half of the REGARDS participants were women (3351 [52.7%]); 1774 (27.9%) were Black and 4585 (72.1%) were White. For the primary diagnosis code, the ICD-10 code list had a sensitivity of 70.7% (95% CI, 63.2%-78.3%) and a specificity of 99.1% (95% CI, 98.9%-99.4%). For any diagnosis code, the ICD-10 code list had a sensitivity of 77.9% (95% CI, 71.0%-84.7%) and a specificity of 98.9% (95% CI, 98.6%-99.2%).

Conclusions and Relevance

These findings suggest that ICD-10 codes could be used to identify incident stroke events in Medicare claims with moderate sensitivity and high specificity.

The impact of stroke on employment income: A cohort study using hospital and income tax data in Ontario, Canada

OBJECTIVE

To document the impact of stroke on employment income among people employed at the time of stroke.

DESIGN

Population-based cohort study.

PARTICIPANTS

People hospitalized for stroke in Ontario, Canada (2010-2014) and people without stroke matched on demographic characteristics.

MAIN MEASURES

Robust Poisson regression to estimate the effects of stroke on the probability of reporting employment income on tax returns over 3 years. Quantile regression difference-in-differences to estimate the changes in annual employment income attributable to stroke.

RESULTS

Stroke survivors were increasingly less likely to report any employment income poststroke, incidence rate ratios (IRR) 0.87 at 1 year (95% confidence intervals [CI]; 0.85-0.88), 0.82 at 2 years (95% CI; 0.81-0.84) and 0.81 at 3 years (95% CI; 0.79-0.82). IRR for reporting at least 50% of prestroke income levels were 0.76 at 1 year (95% CI; 0.75-0.78), 0.75 at 2 years (95% CI; 0.73-0.77) and 0.73 at 3 years (95% CI; 0.71-0.75). IRR for reporting at least 90% of prestroke income levels were 0.72 at 1 year (95% CI; 0.70-0.74), 0.66 at 2 years (95% CI; 0.64-0.68) and again 0.66 at 3 years (95% CI; 0.64-0.68). Relative changes in annual employment income attributable to stroke varied from a decrease of 13.8% (95% CI; 8.7-18.9) at the 75th income percentile to a decrease of 43.1% (95% CI; 18.7-67.6) at the 25th income percentile.

CONCLUSIONS

It is important for healthcare and service providers to recognize the impact of stroke on return to prestroke levels of employment income. Low-income stroke survivors experience a more drastic loss in employment income and may need additional social support.

Association of oxaliplatin-containing adjuvant duration with post-treatment fall-related injury and fracture in patients with stage III colon cancer: a population-based retrospective cohort study

PURPOSE

Oxaliplatin-containing adjuvant chemotherapy yields a significant survival benefit in stage III colon cancer and is the standard of care. Simultaneously, it causes dose-dependent peripheral neuropathy that may increase the risk of fall-related injury (FRI) such as fracture and laceration. Because these events carry significant morbidity and the global burden of colon cancer is on the rise, we examined the association between treatment with a full versus shortened course of adjuvant chemotherapy and post-treatment FRI and fracture.

METHODS

In this overlap propensity score weighted, retrospective cohort study, we included patients aged ≥ 18 years with resected stage III colon cancer diagnosed 2007-2019 and treated with oxaliplatin-containing adjuvant chemotherapy (oxaliplatin plus a fluoropyrimidine; capecitabine [CAPOX] or 5-fluorouracil and leucovorin [FOLFOX]). Propensity score methods facilitate the separation of design from analysis and comparison of baseline characteristics across the weighted groups. Treatment groups were defined as 50% (4 cycles CAPOX/6 cycles FOLFOX) and > 85% (7-8 cycles CAPOX/11-12 cycles FOLFOX) of a maximal course of adjuvant chemotherapy to approximate the treatment durations received in the IDEA collaboration. The main outcomes were time to any FRI and time to fracture. We determined the subdistribution hazard ratios (sHR) estimating the association between FRI/fracture and treatment group, accounting for the competing risk of death.

RESULTS

We included 3,461 patients; 473 (13.7%) received 50% and 2,988 (86.3%) received > 85% of a maximal course of adjuvant therapy. For post-treatment FRI, median follow-up was 4.6 years and total follow-up was 17,968 person-years. There were 508 FRI, 301 fractures, and 692 deaths. Treatment with > 85% of a maximal course of therapy conferred a sHR of 0.84 (95% CI 0.62-1.13) for post-treatment FRI and a sHR of 0.72 (95% CI 0.49-1.06) for post-treatment fracture.

CONCLUSION

For patients with stage III colon cancer undergoing treatment with oxaliplatin-containing adjuvant chemotherapy, any potential neuropathy associated with longer durations of treatment was not found to result in greater rates of FRI and fracture. Within the limits of this retrospective study, our findings suggest concern about FRI, while mechanistically plausible, ought not to determine treatment duration.

Association Between Immigration Status and Ambulatory Secondary Stroke Preventive Care in Ontario, Canada

BACKGROUND AND OBJECTIVES

Secondary stroke preventive care includes evaluation and control of vascular risk factors to prevent stroke recurrence. Our objective was to evaluate the quality of ambulatory stroke preventive care and its variation by immigration status in adult stroke survivors in Ontario, Canada.

METHODS

We conducted a population-based administrative database-derived retrospective cohort study in Ontario, Canada. Using immigration records, we defined immigrants as those immigrating after 1985 and long-term residents as those arriving before 1985 or those born in Canada. We included community-dwelling stroke survivors 40 years and older with a first-ever stroke between 2011 and 2017. In the year following their stroke, we evaluated the following metrics of stroke prevention: testing for hyperlipidemia and diabetes; among those with the condition, control of diabetes (hemoglobin A1c ≤7%) and hyperlipidemia (low-density lipoprotein <2 mmol/L); medication use to control hypertension, diabetes, and atrial fibrillation; and visit to a family physician and a specialist (neurologist, cardiologist, or geriatrician). We determined age and sex-adjusted absolute prevalence difference (APD) between immigrants and long-term residents for each metric using generalized linear models with binomial distribution and an identity link function.

RESULTS

We included 34,947 stroke survivors (median age 70 years, 46.9% women) of whom 12.4% were immigrants. The receipt of each metric ranged from 68% to 90%. Compared with long-term residents, after adjusting for age and sex, immigrants were slightly more likely to receive screening for hyperlipidemia (APD 5.58%; 95% CI 4.18-6.96) and diabetes (5.49%; 3.76-7.23), have visits to family physicians (1.19%; 0.49-1.90), receive a prescription for antihypertensive (3.12%; 1.76-4.49) and antihyperglycemic medications (9.51%; 6.46-12.57), and achieve control of hyperlipidemia (3.82%; 1.01-6.63). By contrast, they were less likely to achieve diabetes control (-4.79%; -7.86 to -1.72) or have visits to a specialist (-1.68%; -3.12 to -0.24). There was minimal variation by region of origin or time since immigration in immigrants.

DISCUSSION

Compared with long-term residents, many metrics of secondary stroke preventive care were better in immigrants, albeit with small absolute differences. However, future work is needed to identify and mitigate the factors associated with the suboptimal quality of stroke preventive care for all stroke survivors.

Trends in Demographic and Geographic Disparities in Stroke Mortality Among Older Adults in the United States

BACKGROUND

Stroke is a leading cause of morbidity and mortality in the United States among older adults. However, the impact of demographic and geographic risk factors remains ambiguous. A clear understanding of these associations and updated trends in stroke mortality can influence health policies and interventions.

METHODS

This study characterizes stroke mortality among older adults (age ≥55) in the US from January 1999 to December 2020, sourcing data from the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research. Segmented regression was used to analyze trends in crude mortality rate and age-adjusted mortality rate (AAMR) per 100,000 individuals stratified by stroke subcategory, sex, ethnicity, urbanization, and state.

RESULTS

A total of 3,691,305 stroke deaths occurred in older adults in the US between 1999 and 2020 (AAMR = 233.3), with an overall decrease in AAMR during these years. The highest mortality rates were seen in nonspecified stroke (AAMR = 173.5), those 85 or older (crude mortality rate1276.7), men (AAMR = 239.2), non-Hispanic African American adults (AAMR = 319.0), and noncore populations (AAMR = 276.1). Stroke mortality decreased in all states from 1999 to 2019 with the greatest and least decreases seen in California (-61.9%) and Mississippi (-35.0%), respectively. The coronavirus pandemic pandemic saw increased stroke deaths in most groups.

CONCLUSIONS

While there's a decline in stroke-related deaths among US older adults, outcome disparities remain across demographic and geographic sectors. The surge in stroke deaths during coronavirus pandemic reaffirms the need for policies that address these disparities.

The influence of diagnostic subgroups, patient- and hospital characteristics for the validity of cardiovascular diagnoses-Data from a Norwegian hospital trust

BACKGROUND

Cardiovascular discharge diagnoses may serve as endpoints in epidemiological studies if they have a high validity. Aim was to study if diagnoses-specific characteristics like type, sub-categories, and position of cardiovascular diagnoses affected diagnostic accuracy.

METHODS

Patients (n = 7,164) with a discharge diagnosis of acute myocardial infarction, heart failure or cerebrovascular disease were included. Data were presented as positive predictive values (PPV) and sensitivity.

RESULTS

PPV was high (≥88%) for acute myocardial infarction (n = 2,189) (except for outpatients). For heart failure (n = 4,026) PPV was 67% overall, but higher (>99%) when etiology or echocardiography was included. For hemorrhagic (n = 257) and ischemic (n = 1,034) strokes PPVs were 87% and 80%, respectively, with sensitivity of 79% and 75%. Transient ischemic attacks (n = 926) had PPV 56%, but sensitivity 86%. Primary diagnoses showed higher validity than subsequent diagnoses and inpatient diagnoses were more valid than outpatient diagnoses (except for transient ischemic attack). The diagnoses of acute myocardial infarction and heart failure where most valid when placed at cardiology units, while ischemic stroke when discharged from an internal medicine unit.

CONCLUSIONS

The diagnoses of acute myocardial infarction and stroke had excellent validity when placed during hospital stays. Similarly, heart failure diagnoses had excellent validity when echocardiography was performed before placing the diagnosis, while overall the diagnoses of heart failure and transient ischemic attack were less valid. In conclusion, the results indicate that cardiovascular diagnoses based on objective findings such as acute myocardial infarction and stroke have excellent validity and may be used as endpoints in clinical epidemiological studies with less rigid validation.

The association between inpatient rehabilitation intensity and outcomes after stroke in Ontario, Canada

BACKGROUND

Several studies have demonstrated improved outcomes poststroke when higher intensity rehabilitation is provided. Canadian Stroke Best Practice Recommendations advise patients receive 180 min of therapy time per day; however, the exact amount required to reach benefit is unknown.

AIMS

The primary aim of this study was to determine the association between rehabilitation intensity (RI) and total Functional Independence Measure (FIM) Instrument change. Secondary aims included determining the association between RI and discharge location, 90-day home time, rehabilitation effectiveness, and motor and cognitive FIM change.

METHODS

A retrospective cohort study was conducted using available administrative databases of acute stroke patients discharged to inpatient rehabilitation facilities in Ontario, Canada, from January 2017 to December 2021. RI was defined as number of minutes per day of direct therapy by all providers divided by rehabilitation length of stay. The association between RI and the outcomes of interest were analyzed using regression models with restricted cubic splines.

RESULTS

A total of 12,770 individuals were included. Mean age of the sample was 72.6 years, 46.0% of individuals were female, and 87.6% had an ischemic stroke. Mean RI was 74.7 min (range: 5-162 min) per day. Increased RI was associated with an increase in mean FIM change. However, there was diminishing incremental increase after reaching 95 min/day. Increased RI was positively associated with motor and cognitive FIM change, rehabilitation effectiveness, 90-day home time, and discharge to preadmission setting. Higher RI was associated with a lower likelihood of discharge to long-term care.

CONCLUSIONS

None of the patients met the recommended RI of 180 min/day based on the Canadian Stroke Best Practice Recommendations. Despite this, higher intensity was associated with better outcomes. Given that most positive associations were observed with a RI ⩾95 min/day, this may be a more feasible target.

Poststroke Care Pathways and Spasticity Treatment: A Retrospective Study in Alberta

BACKGROUND

Limited evidence exists regarding care pathways for stroke survivors who do and do not receive poststroke spasticity (PSS) treatment.

METHODS

Administrative data was used to identify adults who experienced a stroke and sought acute care between 2012 and 2017 in Alberta, Canada. Pathways of stroke care within the health care system were determined among those who initiated PSS treatment (PSS treatment group: outpatient pharmacy dispensation of an anti-spastic medication, focal chemo-denervation injection, or a spasticity tertiary clinic visit) and those who did not (non-PSS treatment group). Time from the stroke event until spasticity treatment initiation, and setting where treatment was initiated were reported. Descriptive statistics were performed.

RESULTS

Health care settings within the pathways of stroke care that the PSS (n = 1,079) and non-PSS (n = 22,922) treatment groups encountered were the emergency department (86 and 84%), acute inpatient care (80 and 69%), inpatient rehabilitation (40 and 12%), and long-term care (19 and 13%), respectively. PSS treatment was initiated a median of 291 (interquartile range 625) days after the stroke event, and most often in the community when patients were residing at home (45%), followed by "other" settings (22%), inpatient rehabilitation (18%), long-term care (11%), and acute inpatient care (4%).

CONCLUSIONS

To our knowledge, this is the first population based cohort study describing pathways of care among adults with stroke who subsequently did or did not initiate spasticity treatment. Areas for improvement in care may include strategies for earlier identification and treatment of PSS.

Stroke risk in women with atrial fibrillation

BACKGROUND AND AIMS

Female sex is associated with higher rates of stroke in atrial fibrillation (AF) after adjustment for other CHA2DS2-VASc factors. This study aimed to describe sex differences in age and cardiovascular care to examine their relationship with stroke hazard in AF.

METHODS

Population-based cohort study using administrative datasets of people aged ≥66 years diagnosed with AF in Ontario between 2007 and 2019. Cause-specific hazard regression was used to estimate the adjusted hazard ratio (HR) for stroke associated with female sex over a 2-year follow-up. Model 1 included CHA2DS2-VASc factors, with age modelled as 66-74 vs. ≥ 75 years. Model 2 treated age as a continuous variable and included an age-sex interaction term. Model 3 further accounted for multimorbidity and markers of cardiovascular care.

RESULTS

The cohort consisted of 354 254 individuals with AF (median age 78 years, 49.2% female). Females were more likely to be diagnosed in emergency departments and less likely to receive cardiologist assessments, statins, or LDL-C testing, with higher LDL-C levels among females than males. In Model 1, the adjusted HR for stroke associated with female sex was 1.27 (95% confidence interval 1.21-1.32). Model 2 revealed a significant age-sex interaction, such that female sex was only associated with increased stroke hazard at age >70 years. Adjusting for markers of cardiovascular care and multimorbidity further decreased the HR, so that female sex was not associated with increased stroke hazard at age ≤80 years.

CONCLUSION

Older age and inequities in cardiovascular care may partly explain higher stroke rates in females with AF.

Validity of Routine Health Data To Identify Safety Outcomes of Interest For Covid-19 Vaccines and Therapeutics in the Context of the Emerging Pandemic: A Comprehensive Literature Review

Introduction

Regulatory guidance encourages transparent reporting of information on the quality and validity of electronic health record data being used to generate real-world benefit-risk evidence for vaccines and therapeutics. We aimed to provide an overview of the availability of validated diagnostic algorithms for selected safety endpoints for Coronavirus disease 2019 (COVID-19) vaccines and therapeutics in the context of the emerging pandemic prior to December 2020.

Methods

We reviewed the literature up to December 2020 to identify validation studies for various safety events of interest, including myocardial infarction, arrhythmia, myocarditis, acute cardiac injury, vasculitis/vasculopathy, venous thromboembolism, stroke, respiratory distress syndrome (RDS), pneumonitis, cytokine release syndrome (CRS), multiple organ dysfunction syndrome, and renal failure. We included studies published between 2015 and 2020 that were considered high quality assessed with QUADAS and that reported positive predictive values (PPVs).

Results

Out of 43 identified studies, we found that diagnostic algorithms for cardiovascular outcomes were supported by the highest number of validation studies (n=17). Accurate algorithms are available for myocardial infarction (median PPV 80%; IQR 22%), arrhythmia (PPV range >70%), venous thromboembolism (median PPV: 73%) and ischaemic stroke (PPV range ≥85%). We found a lack of validation studies for less common respiratory and cardiac safety outcomes of interest (eg, pneumonitis and myocarditis), as well as for COVID-specific complications (CRS, RDS).

Conclusion

There is a need for better understanding of barriers to conducting validation studies, including data governance restrictions. Regulatory guidance should promote embedding validation within real-world EHR research used for decision-making.

Association Between Stroke Severity and Serum Troponin in Acute Stroke

Serum troponin is often elevated in patients with acute stroke and its mechanism is unknown. In a retrospective single-center cohort study, we evaluated the association between stroke severity and serum troponin in 187 patients with acute stroke using multivariable modified Poisson models. A one-point increase in the National Institutes of Health Stroke Scale (measure of stroke severity) was associated with a marginally higher serum troponin level in adjusted models (aIRR 1.03; 1.01-1.05, P = 0.001). The modest, yet potentially independent, association between stroke severity and serum troponins could suggest a neurogenic basis for a cardiac injury in patients with acute stroke.

Previous Ischemic Stroke Significantly Alters Stroke Risk in Newly Diagnosed Cancer Patients

BACKGROUND

Previous ischemic stroke (IS) is a risk factor for subsequent IS in the general population; it is unclear if this relationship remains true in patients with cancer. Our objective was to examine the association between previous IS and risk for future IS in individuals newly diagnosed with cancer.

METHODS

We conducted a retrospective population-based matched cohort study of newly diagnosed adult cancer patients (excluding nonmelanoma skin cancers and primary central nervous system tumors) in Ontario, Canada from 2010 to 2020; those with prior IS were matched (1:4) by age, sex, year of cancer diagnosis, cancer stage, and cancer site to those without a history of stroke. Cumulative incidence function curves were created to estimate the incidence of IS. Subdistribution adjusted hazard ratios (aHRs) and 95% CIs were calculated, where death was treated as a competing event. Multivariable analysis was adjusted for imbalanced baseline characteristics.

RESULTS

We examined 65 525 individuals with cancer, including 13 070 with a history of IS. The median follow-up duration was 743 days (interquartile range, 177-1729 days). The incidence of IS following cancer diagnosis was 261.3/10 000 person-years in the cohort with prior IS and 75.3/10 000 person-years in those without prior IS. Individuals with prior IS had an increased risk for IS after cancer diagnosis compared with those without a history (aHR, 2.68 [95% CI, 2.41-2.98]); they also had more prevalent cardiovascular risk factors. The highest risk for stroke compared with those without a history of IS was observed in the gynecologic cancer (aHR, 3.84 [95% CI, 2.15-6.85]) and lung cancer (aHR, 3.18 [95% CI, 2.52-4.02]) subgroups. The risk of IS was inversely correlated with lag time of previous stroke; those with IS 1 year before their cancer diagnosis had the highest risk (aHR, 3.68 [95% CI, 3.22-4.22]).

CONCLUSIONS

Among individuals with newly diagnosed cancer, those with IS history were almost 3× more likely to experience a stroke after cancer diagnosis, especially if the prediagnosis stroke occurred within 1 year preceding cancer diagnosis.

Attributable Costs of Stroke in Ontario, Canada and Their Variation by Stroke Type and Social Determinants of Health

BACKGROUND

Estimates of attributable costs of stroke are scarce, as most prior studies do not account for the baseline health care costs in people at risk of stroke. We estimated the attributable costs of stroke in a universal health care setting and their variation across stroke types and several social determinants of health.

METHODS

We undertook a population-based administrative database-derived matched retrospective cohort study in Ontario, Canada. Community-dwelling adults aged ≥40 years with a stroke between 2003 and 2018 were matched (1:1) on demographics and comorbidities with controls without stroke. Using a difference-in-differences approach, we estimated the mean 1-year direct health care costs attributable to stroke from a public health care payer perspective, accounting for censoring with a weighted available sample estimator. We described health sector-specific costs and reported variation across stroke type and social determinants of health.

RESULTS

The mean 1-year attributable costs of stroke were Canadian dollars 33 522 (95% CI, $33 231-$33 813), with higher costs for intracerebral hemorrhage ($40 244; $39 193-$41 294) than ischemic stroke ($32 547; $32 252-$32 843). Most of these costs were incurred in acute care hospitals ($15 693) and rehabilitation facilities ($7215). Compared with all patients with stroke, the mean attributable costs were higher among immigrants ($40 554; $39 316-$41 793), those aged <65 years ($35 175; $34 533-$35 818), and those residing in low-income neighborhoods ($34 687; $34 054-$35 320) and lower among rural residents ($29 047; $28 362-$29 731).

CONCLUSIONS

Our findings of high attributable costs of stroke, especially in immigrants, younger patients, and residents of low-income neighborhoods, can be used to evaluate potential health care cost savings associated with different primary stroke prevention strategies.

Estimating the Number of Hospital or Emergency Department Presentations for Stroke in Canada

BACKGROUND

Although age-standardized stroke occurrence has been decreasing, the absolute number of stroke events globally, and in Canada, is increasing. Stroke surveillance is necessary for health services planning, informing research design, and public health messaging. We used administrative data to estimate the number of stroke events resulting in hospital or emergency department presentation across Canada in the 2017-18 fiscal year.

METHODS

Hospitalization data were obtained from the Canadian Institute for Health Information (CIHI) Discharge Abstract Database and the Ministry of Health and Social Services in Quebec. Emergency department data were obtained from the CIHI National Ambulatory Care Reporting System (Alberta and Ontario). Stroke events were identified using ICD-10 coding. Data were linked into episodes of care to account for readmissions and interfacility transfers. Projections for emergency department visits for provinces/territories outside of Alberta and Ontario were generated based upon age and sex-standardized estimates from Alberta and Ontario.

RESULTS

In the 2017-18 fiscal year, there were 108,707 stroke events resulting in hospital or emergency department presentation across the country. This was made up of 54,357 events resulting in hospital admission and 54,350 events resulting in only emergency department presentation. The events resulting in only emergency department presentation consisted of 25,941 events observed in Alberta and Ontario and a projection of 28,409 events across the rest of the country.

CONCLUSIONS

We estimate a stroke event resulting in hospital or emergency department presentation occurs every 5 minutes in Canada.

Polygenic Risk of Epilepsy and Post-Stroke Epilepsy

Background and Aims

Epilepsy is highly heritable, with numerous known genetic risk loci. However, the genetic predisposition's role in post-acute brain injury epilepsy remains understudied. This study assesses whether a higher genetic predisposition to epilepsy raises post-stroke or Transient Ischemic Attack (TIA) survivor's risk of Post-Stroke Epilepsy (PSE).

Methods

We conducted a three-stage genetic analysis. First, we identified independent epilepsy-associated ( p <5x10 -8 ) genetic variants from public data. Second, we estimated PSE-specific variant weights in stroke/TIA survivors from the UK Biobank. Third, we tested for an association between a polygenic risk score (PRS) and PSE risk in stroke/TIA survivors from the All of Us Research Program. Primary analysis included all ancestries, while a secondary analysis was restricted to European ancestry only. A sensitivity analysis excluded TIA survivors. Association testing was conducted via multivariable logistic regression, adjusting for age, sex, and genetic ancestry.

Results

Among 19,708 UK Biobank participants with stroke/TIA, 805 (4.1%) developed PSE. Likewise, among 12,251 All of Us participants with stroke/TIA, 394 (3.2%) developed PSE. After establishing PSE-specific weights for 39 epilepsy-linked genetic variants in the UK Biobank, the resultant PRS was associated with elevated odds of PSE development in All of Us (OR:1.16[1.02-1.32]). A similar result was obtained when restricting to participants of European ancestry (OR:1.23[1.02-1.49]) and when excluding participants with a TIA history (OR:1.18[1.02-1.38]).

Conclusions

Our findings suggest that akin to other forms of epilepsy, genetic predisposition plays an essential role in PSE. Because the PSE data were sparse, our results should be interpreted cautiously.

Validation of diagnosis of acute myocardial infarction and stroke in electronic medical records: a primary care cross-sectional study in Madrid, Spain (the e-MADVEVA Study)

OBJECTIVES

To validate the diagnoses of acute myocardial infarction (AMI) and stroke recorded in electronic medical records (EMR) and to estimate the population prevalence of both diseases in people aged ≥18 years.

DESIGN

Cross-sectional validation study.

SETTING

45 primary care centres.

PARTICIPANTS

Simple random sampling of diagnoses of AMI and stroke (International Classification of Primary Care-2 codes K75 and K90, respectively) registered by 55 physicians and random age-matched and sex-matched sampling of the records that included in primary care EMRs in Madrid (Spain).

PRIMARY AND SECONDARY OUTCOME MEASURES

Sensitivity, specificity, positive and negative predictive values and overall agreement were calculated using the kappa statistic. Applied gold standards were ECGs, brain imaging studies, hospital discharge reports, cardiology reports and neurology reports. In the case of AMI, the ESC/ACCF/AHA/WHF Expert Consensus Document was also used. Secondary outcomes were the estimated prevalence of both diseases considering the sensitivity and specificity obtained (true prevalence).

RESULTS

The sensitivity of a diagnosis of AMI was 98.11% (95% CI, 96.29 to 99.03), and the specificity was 97.42% (95% CI, 95.44 to 98.55). The sensitivity of a diagnosis of stroke was 97.56% (95% CI, 95.56 to 98.68), and the specificity was 94.51% (95% CI, 91.96 to 96.28). No differences in the results were found after stratification by age and sex (both diseases). The prevalence of AMI and stroke was 1.38% and 1.27%, respectively.

CONCLUSION

The validation results show that diagnoses of AMI and stroke in primary care EMRs constitute a helpful tool in epidemiological studies. The prevalence of AMI and stroke was lower than 2% in the population aged over 18 years.

In-hospital outcomes and recurrence of stroke during pregnancy and puerperium

BACKGROUND

There are limited data regarding the best management and outcomes of acute stroke during pregnancy and the puerperium.

METHODS

Pregnancy-related hospitalizations with age > 18 years were identified from the Nationwide Readmissions Database 2016-2018. The study cohort consisted of all patients with acute stroke and a 5% random sample of the remaining non-stroke hospitalizations. Logistic regression and survival analyses were used to compare the in-hospital outcomes and readmissions in patients with and without acute stroke.

RESULTS

There were 11,829,044 pregnancy-related hospitalizations, of which 4057 had acute stroke. The mean ± SD age of the study cohort was 29.0 ± 5.7 years. Among patients with acute ischemic stroke, 60 (3.7%) patients received intravenous thrombolysis and 112 (6.8%) patients underwent endovascular thrombectomy. Among patients with intracranial hemorrhage, 205 (10.5%) patients underwent ventriculostomy and 18 (0.9%) patients underwent decompressive craniotomy. Patients with stroke had longer length of stay (mean: 10.7 vs 2.7 days), higher in-hospital mortality (4.6% vs 0.0001%) and were less likely to discharge home (73.0% vs 98.6%). Non-elective readmission within 90 days of discharge occurred in 14.8% of patients with stroke versus in 3.9% of patients without stroke. Readmissions due to cerebrovascular events occurred in 2.3% of patients with stroke versus in 0.007% of patients without stroke within 1 year of discharge, with mean ± SD time to readmission 66.2 ± 78.0 days.

CONCLUSION

Stroke is a serious complication of pregnancy, associated with high morbidity and mortality. Recurrence of stroke occurs in a small proportion of patients, and the risk is highest during the initial 3 months.

Maternal Health Outcomes After Pregnancy-Associated Stroke: A Population-Based Study With 19 Years of Follow-Up

BACKGROUND

Pregnancy-associated stroke carries high short-term morbidity and mortality, but data on subsequent maternal outcomes are limited. We evaluated long-term maternal health outcomes after pregnancy-associated stroke.

METHODS

In this retrospective cohort study, we used administrative data to identify pregnant adults aged ≤49 years with stroke between 2002-2020 in Ontario, Canada and 2 comparison groups: (1) non-pregnant female patients with stroke and (2) pregnant patients without stroke. Patients who survived the index admission were followed until 2021. After propensity score matching, we used Cox regression with a robust variance estimator to compare pregnant patients with stroke and the 2 comparison groups for the composite outcome of death and all-cause non-pregnancy readmission. Where proportional hazard assumption was not met, we reported time-varying hazard ratios (HR) with 95% CIs by modeling the log-hazard ratio as a function of time using restricted cubic splines.

RESULTS

We identified 217 pregnant patients with stroke, 7604 non-pregnant patients with stroke, and 1 496 256 pregnant patients without stroke. Of the 202 pregnant patients with stroke who survived the index stroke admission, 41.6% (6.8 per 100 person-years) subsequently died or were readmitted during follow-up. Median follow-up times were 5 years (pregnancy-associated stroke), 3 years (non-pregnant stroke), and 8 years (pregnant without stroke). Pregnant patients with stroke had a lower hazard of death and all-cause readmission compared with non-pregnant patients with stroke at 1-year follow-up (HR, 0.64 [95% CI, 0.44-0.94]), but this association did not persist during longer-term follow-up. Conversely, pregnant patients with stroke had higher hazard of death and readmission compared with pregnant patients without stroke at 1-year follow-up (HR, 5.70 [95% CI, 3.04-10.66]), and this association persisted for a decade.

CONCLUSIONS

Stroke during pregnancy is associated with long-term health consequences. It is essential to transition care postpartum to primary or specialty care to optimize vascular health.

Effectiveness and safety of direct oral anticoagulants in patients with venous thromboembolism and creatinine clearance < 30 mL/min

The few studies that compared direct oral anticoagulants (DOAC) vs. warfarin in the setting of advanced renal insufficiency have focused on patients with atrial fibrillation. The purpose of this observational, matched, cohort study of patients was to assess the effectiveness and safety of DOAC vs. warfarin for the treatment of venous thromboembolism (VTE) among patients with a creatinine clearance (CrCl) < 30 mL/min. This observational, cohort study included patients with VTE and CrCl < 30 mL/min who were newly initiated on a DOAC or warfarin between January 1, 2016 and December 31, 2020. DOAC patients were matched up to 1:2 to warfarin patients. Primary outcome was a composite of recurrent VTE, clinically-relevant bleeding, ischemic stroke, and all-cause mortality. Adjusted conditional, multivariate Cox proportional hazards modeling was used to assess outcomes. 626 DOAC patients were matched to 1071 warfarin patients. DOAC patients had a higher mean age, higher mean baseline CrCl, and were less likely to have been receiving dialysis. There was no statistically significant difference in the composite outcome between groups (adjusted hazard ratio [aHR] 1.13, 95% confidence interval [CI] 0.87-1.47) or in the individual components of the composite (all HR 95% CI crossed 1.00). Identification of statistically non-significant rates of bleeding and thromboembolic outcomes suggest that the use of DOAC or warfarin is reasonable in patients with VTE and CrCl < 30 mL/min.

Sex Differences in Intensity of Care and Outcomes After Acute Ischemic Stroke Across the Age Continuum

BACKGROUND AND OBJECTIVES

Sex differences in stroke care and outcomes have been previously reported, but it is not known whether these associations vary across the age continuum. We evaluated whether the magnitude of female-male differences in care and outcomes varied with age.

METHODS

In a population-based cohort study, we identified patients hospitalized with ischemic stroke between 2012 and 2019 and followed through 2020 in Ontario, Canada, using administrative data. We evaluated sex differences in receiving intensive care unit services, mechanical ventilation, gastrostomy tube insertion, comprehensive stroke center care, stroke unit care, thrombolysis, and endovascular thrombectomy using logistic regression and reported odds ratios (ORs) and 95% CIs. We used Cox proportional hazard models and reported the hazard ratios (HRs) and 95% CI of death within 90 or 365 days. Models were adjusted for covariates and included an interaction between age and sex. We used restricted cubic splines to model the relationship between age and care and outcomes. Where the p-value for interaction was statistically significant (p < 0.05), we reported age-specific OR or HR.

RESULTS

Among 67,442 patients with ischemic stroke, 45.9% were female and the median age was 74 years (64-83). Care was similar between both sexes, except female patients had higher odds of receiving endovascular thrombectomy (OR 1.35, 95% CI [1.19-1.54] comparing female with male), and these associations were not modified by age. There was no overall sex difference in hazard of death (HR 95% CI 0.99 [0.95-1.04] for death within 90 days; 0.99 [0.96-1.03] for death within 365 days), but these associations were modified by age with the hazard of death being higher in female than male patients between the ages of 50-70 years (most extreme difference around age 57, HR 95% CI 1.25 [1.10-1.40] at 90 days, p-interaction 0.002; 1.15 [1.10-1.20] at 365 days, p-interaction 0.002).

DISCUSSION

The hazard of death after stroke was higher in female than male patients aged 50-70 years. Examining overall sex differences in outcomes without accounting for the effect modification by age may miss important findings in specific age groups.

Validating emergency department cardioversion procedures in provincial administrative data in Ontario, Canada

BACKGROUND

Cardioversion of acute-onset atrial fibrillation (AF) via electrical or pharmacological means is a common procedure performed in many emergency departments. While these procedures appear to be very safe, the rarity of subsequent adverse outcomes such as stroke would require huge sample sizes to confirm that conclusion. Big data can supply such sample sizes.

OBJECTIVE

We aimed to validate several potential codes for successful emergency department cardioversion of AF patients.

METHODS

This study combined 3 observational datasets of emergency department AF visits seen at one of 26 hospitals in Ontario, Canada, between 2008 and 2012. We linked patients who were eligible for emergency department cardioversion to several province-wide health administrative datasets to search for the associated cardioversion billing and procedural codes. Using the observational data as the gold standard for successful cardioversion, we calculated the test characteristics of a billing code (Z437) and of procedural codes 1.HZ.09JAFS and 1.HZ.09JAJS. Both include pharmacological and electrical cardioversions, as well as unsuccessful attempts; the latter is <10% using electricity (in Canada, standard practice is to proceed to electrical cardioversion if pharmacological cardioversion is unsuccessful).

RESULTS

Of 4557 unique patients in the three datasets, 2055 (45.1%) were eligible for cardioversion. Nine hundred thirty-three (45.4%) of these were successfully cardioverted to normal sinus rhythm. The billing code had slightly better test characteristics overall than the procedural codes. Positive predictive value (PPV) of a billing was 89.8% (95% CI, 87.0-92.2), negative predictive value (NPV) 70.5% (95% CI, 68.1-72.8), sensitivity 52.1% (95% CI, 48.8-55.3), and specificity 95.1% (95% CI, 93.7-96.3).

CONCLUSIONS

AF patients who have been successfully cardioverted in an emergency department can be identified with high PPV and specificity using a billing code. Studies that require high sensitivity for cardioversion should consider other methods to identify cardioverted patients.

Gender inequality in source country modifies sex differences in stroke incidence in Canadian immigrants

Research suggests that gender inequality, measured using the gender inequality index (GII), influences stroke mortality in women compared to men. We examine how source country GII modifies the rate of ischemic stroke in women compared to men after immigration to Canada, a country with low gender inequality. We used linked health data and immigration records of 452,089, stroke-free immigrants aged 40-69 year who migrated from 123 countries. Over 15 years of follow-up, 5991 (1.3%) had an incident ischemic stroke. We demonstrate (a) a lower adjusted rate of stroke in women compared to men (hazard ratio 0.64; 95% CI 0.61-0.67); (b) that sex differences in stroke incidence were modified by source country GII, as the hazard of stroke in women vs. men attenuated by a factor of 1.06 for every 0.1 increase in the GII of the source country (P_sex*GII = 0.002); and (c) migration to a country with low GII attenuates the adverse effect of source country GII on sex differences in stroke incidence. Evaluating pathways through which source country gender inequality differentially influences stroke risk in immigrant women compared to men could help develop strategies to mitigate the effects of early-life gender inequality on stroke risk.

Proportion of life spent in Canada and stroke incidence and outcomes in immigrants

BACKGROUND

To evaluate the association between the proportion of life spent in a host nation and stroke incidence and outcomes among Canadian immigrants.

METHODS

We conducted a retrospective cohort study of 1.2 million adult Canadian immigrants (mean age 40 [±14.6] years, 50.5% women) who were followed between 2003 and 2018 using linked administrative health data. Using multivariable cause-specific hazard models, we evaluated the overall and sex-specific associations between the proportion of life spent in Canada (φ), modeled as restricted cubic splines, and ischemic stroke incidence and outcomes.

RESULTS

Compared to the median proportion of life in Canada (φ = 0.2), a J-shaped association between the proportion of life in Canada and ischemic stroke incidence and outcomes was observed. The adjusted hazard ratios of stroke incidence increased with both progressively lower and higher levels of φ [e.g., (HR_{φ =0.05 vs.φ = 0.20}, 1.15; 1.09-1.21) and (_{HRφ = 0.50 vs. φ = 0.20}, 1.45; 1.27-1.66)]. In sex-stratified analyses, the associations between φ and stroke incidence and outcomes were significant in men, but not in women.

CONCLUSIONS

Stroke incidence and outcomes among immigrants varies with the proportion of life spent in Canada. Future work should identify factors driving the observed associations and the sex differences.

Evaluating the time-varying risk of hypertension, cardiac events, and mortality following Kawasaki disease diagnosis

BACKGROUND

This study evaluated the risk of hypertension, major adverse cardiac events (MACE), and all-cause mortality in Kawasaki disease (KD) patients up to young adulthood.

METHODS

An inception cohort of 1169 KD patients between 1991 and 2008 from a tertiary-level hospital in Ontario, Canada was linked with health administrative data to ascertain outcomes up to 28 years of follow-up. Their risk was compared with 11,690 matched population comparators. The primary outcome was hypertension and secondary outcomes were MACE and death.

RESULTS

After a median follow-up of 20 years [IQR: 8.3], the cumulative incidence of hypertension and MACE in the KD group was 3.8% (95% CI: 2.5-5.5) and 1.2% (95% CI: 0.6-2.4%), respectively. The overall survival probability in the KD group was 98.6% (95% CI: 97.2-99.3%). Relative to comparators, KD patients were at an increased risk for hypertension [aHR: 2.2 (95% CI: 1.5-3.4)], death [aHR: 2.5 (95% CI: 1.3-5.0)], and MACE [aHR: 10.7 (95% CI: 6.4-17.9)]. For hypertension and MACE, the aHR was the highest following diagnosis and then the excess risk diminished after 16 and 13 years of follow-up, respectively. MACE occurred largely in KD patients with coronary aneurysms [cumulative incidence: 12.8%].

CONCLUSIONS

KD patients demonstrated a reassuring cardiac prognosis up to young adulthood with low events and excellent survival. KD patients were at increased risk for hypertension, but this excess risk occurred early and declined with time.

IMPACT

With the current standard of care, KD patients demonstrated favorable cardiac prognosis, with low events of hypertension, MACE, and excellent survival. Hypertension and MACE risk appear to be highest around the time of KD diagnosis. MACE occurred primarily in KD patients with coronary aneurysms. Our findings are reassuring to KD patients, families, and their providers. Our study demonstrated an association between KD exposure and hypertension. This association is relatively novel. Previous studies have remained conflicting if KD contributes to long-term atherosclerotic risk.

Validity of Methods to Identify Individuals With Lower Extremity Amputation Using Department of Veterans Affairs Electronic Medical Records

Objectives

To determine the positive predictive value (PPV) of algorithms to identify patients with major (at the ankle or more proximal) lower extremity amputation (LEA) using Department of Veterans Affairs electronic medical records (EMR) and to evaluate whether PPV varies by sex, age, and race.

Design

We conducted a validation study comparing EMR determined LEA status to self-reported LEA (criterion standard).

Setting

Veterans who receive care at the Department of Veterans Affairs.

Participants

We invited a national sample of patients (N=699) with at least 1 procedure or diagnosis code for major LEA to participate. We oversampled women, Black men, and men ≤40 years of age.

Interventions

Not applicable.

Main Outcome Measure

We calculated PPV estimates and false negative percentages for 7 algorithms using EMR LEA procedure and diagnosis codes relative to self-reported major LEA.

Results

A total of 466 veterans self-reported their LEA status (68%). PPVs for the 7 algorithms ranged from 89% to 100%. The algorithm that required a single diagnosis or procedure code had the lowest PPV (89%). The algorithm that required at least 1 procedure code had the highest PPV (100%) but also had the highest proportion of false negatives (66%). Algorithms that required at least 1 procedure code or 2 or more diagnosis codes 1 month to 1 year apart had high PPVs (98%-99%) but varied in terms of false negative percentages. PPV estimates were higher among men than women but did not differ meaningfully by age or race, after accounting for sex.

Conclusion

PPVs were higher if 1 procedure or at least 2 diagnosis codes were required; the difference between algorithms was marked by sex. Investigators should consider trade-offs between PPV and false negatives to identify patients with LEA using EMRs.

The association between anticoagulation and adverse outcomes after a positive SARS-CoV-2 test among older outpatients: A population-based cohort study

Introduction

Anticoagulation may improve outcomes in patients with COVID-19 when started early in the course of illness.

Materials and methods

This was a population-based cohort study using linked administrative datasets of outpatients aged ≥65 years old testing positive for SARS-CoV-2 between January 1 and December 31, 2020 in Ontario, Canada. The key exposure was anticoagulation with warfarin or direct oral anticoagulants before COVID-19 diagnosis. We calculated propensity scores and used matching weights (MWs) to reduce baseline differences between anticoagulated and non-anticoagulated patients. The primary outcome was a composite of death or hospitalization within 60 days of a positive SARS-CoV-2 test. We used the Kaplan-Meier method and cumulative incidence functions to estimate risk of the primary and component outcomes at 60 days.

Results

We studied 23,159 outpatients (mean age 78.5 years; 13,474 [58.2%] female), among whom 3200 (13.8%) deaths and 3183 (13.7%) hospitalizations occurred within 60 days of the SARS-CoV-2 test. After application of MWs, the 60-day risk of death or hospitalization was 29.2% (95% CI 27.4%–31.2%) for anticoagulated individuals and 32.1% (95% CI 30.7%–33.5%) without anticoagulation (absolute risk difference [ARD], −2.9%; p = 0.005). Anticoagulation was also associated with a lower risk of death: 18.6% (95% CI 17.0%–20.2%) with anticoagulation and 20.9% (95% CI 19.7%–22.2%) in non-anticoagulated patients (ARD -2.3%; p = 0.005).

Conclusions

Among outpatients aged ≥65 years, oral anticoagulation at the time of a positive SARS-CoV-2 test was associated with a lower risk of a composite of death or hospitalization within 60 days.

Association of Diabetes Duration and Glycemic Control With Stroke Rate in Patients With Atrial Fibrillation and Diabetes: A Population-Based Cohort Study

Background

There are limited data on the association of diabetes duration and glycemic control with stroke risk in atrial fibrillation (AF). Our objective was to study the association of diabetes duration and glycated hemoglobin (HbA1c) with the rate of stroke in people with diabetes and newly diagnosed AF.

Methods and Results

This was a population‐based cohort study using linked administrative data sets. We studied 37 209 individuals aged ≥66 years diagnosed with AF in Ontario between April 2009 and March 2019, who had diabetes diagnosed 1 to 16 years beforehand. The primary outcome was hospitalization for stroke at 1 year. Cause‐specific hazard regression was used to model the association of diabetes duration and glycated hemoglobin (HbA1c) with the rate of stroke. Restricted cubic spline analyses showed increasing hazard ratios (HR) for stroke with longer diabetes duration that plateaued after 10 years and increasing HRs for stroke with HbA1c levels >7%. Relative to patients with <5 years diabetes duration, stroke rates were significantly higher for patients with ≥10 years duration (HR, 1.45; 95% CI, 1.16–1.82; P=0.001), while diabetes duration 5 to <10 years was not significantly different. Relative to glycated hemoglobin 6% to <7%, values ≥8% were associated with higher stroke rates (HR, 1.44; 95% CI, 1.12–1.84; P=0.004), while other HbA1c categories were not significantly different.

Conclusions

Longer diabetes duration and higher glycated hemoglobin were associated with significantly higher stroke rates in patients with AF and diabetes. Models for stroke risk prediction and preventive care in AF may be improved by considering patients’ diabetes characteristics.

Association of material deprivation with discharge location and length of stay after inpatient stroke rehabilitation in Ontario: a retrospective, population-based cohort study

BACKGROUND

Low socioeconomic status is associated with increased risk of stroke and worse poststroke functional status. The aim of this study was to determine whether socioeconomic status, as measured by material deprivation, is associated with direct discharge to long-term care or length of stay after inpatient stroke rehabilitation.

METHODS

We performed a retrospective, population-based cohort study of people admitted to inpatient rehabilitation in Ontario, Canada, after stroke. Community-dwelling adults (aged 19-100 yr) discharged from acute care with a most responsible diagnosis of stroke between Sept. 1, 2012, and Aug. 31, 2017, and subsequently admitted to an inpatient rehabilitation bed were included. We used a multivariable logistic regression model to examine the association between material deprivation quintile (from the Ontario Marginalization Index) and discharge to long-term care, and a multivariable negative binomial regression model to examine the association between material deprivation quintile and rehabilitation length of stay.

RESULTS

A total of 18 736 people were included. There was no association between material deprivation and direct discharge to long-term care (most v. least deprived: odds ratio [OR] 1.07, 95% confidence interval [CI] 0.89-1.28); however, people living in the most deprived areas had a mean length of stay 1.7 days longer than that of people in the least deprived areas (p = 0.004). This difference was not significant after adjustment for other baseline differences (relative change in mean 1.02, 95% CI 0.99-1.04).

INTERPRETATION

People admitted to inpatient stroke rehabilitation in Ontario had similar discharge destinations and lengths of stay regardless of their socioeconomic status. In future studies, investigators should consider further examining the associations of material deprivation with upstream factors as well as potential mitigation strategies.

Clinical outcomes of dabigatran use in patients with non-valvular atrial fibrillation and weight >120 kg

BACKGROUND

Patients with obesity were underrepresented in studies evaluating the safety and effectiveness of direct oral anticoagulants (DOAC) in patients with non-valvular atrial fibrillation (NVAF). This study compared clinical outcomes in patients with NVAF and weighing >120 kg and ≤120 kg who were receiving dabigatran.

MATERIALS AND METHODS

This retrospective, matched, longitudinal cohort study included patients from three integrated healthcare delivery systems. Patients ≥18 years of age with NVAF were included if between September 1, 2016 and June 30, 2019 they received dabigatran. Patients >120 kg and ≤120 kg were matched up to 1:6 on age, sex, and CHA₂DS₂-VASc score. Data were extracted from administrative databases. The primary outcome was a composite of ischemic stroke, clinically-relevant bleeding, systemic embolism, and all-cause mortality. Multivariable regression analyses were performed.

RESULTS

777 and 3522 patients >120 kg and ≤120 kg, respectively, were matched. The >120 kg group tended to be younger with a higher burden of chronic disease. There was no difference between groups in the composite outcome (adjusted hazard ratio [AHR] 1.10, 95% confidence interval 0.89-1.37) or individual components of the composite. A subanalysis of clinically-relevant bleeding identified that patients >120 kg were at a greater risk of gastrointestinal bleeding (AHR 1.44, 95% CI 1.01-2.05).

CONCLUSIONS

In patients with NVAF and >120 kg, dabigatran use was associated with a small increased risk of gastrointestinal bleeding but no differences in stroke, mortality or clinically-relevant bleeding. These findings suggest that dabigatran use is reasonable in patients with NVAF and weight >120 kg.

Emergency Department Visits, Care, and Outcome After Stroke and Myocardial Infarction During the COVID-19 Pandemic Phases

Background

It is not known if initial reductions in hospitalization for stroke and myocardial infarction early during the coronavirus disease–2019 pandemic were followed by subsequent increases. We describe the rates of emergency department visits for stroke and myocardial infarction through the pandemic phases.

Methods

We used linked administrative data to compare the weekly age- and sex-standardized rates of visits for stroke and myocardial infarction in Ontario, Canada in the first 9 months of 2020 to the mean baseline rates (2015-2019) using rate ratios (RRs) and 95% confidence intervals (CIs). We compared care and outcomes by pandemic phases (pre-pandemic was January-March, lockdown was March-May, early reopening was May-July, and late reopening was July-September).

Results

We identified 15,682 visits in 2020 for ischemic stroke (59.2%; n = 9279), intracerebral hemorrhage (12.2%; n = 1912), or myocardial infarction (28.6%; n = 4491). The weekly rates for stroke visits in 2020 were lower during the lockdown and early reopening than at baseline (RR 0.76, 95% CI [0.66, 0.87] for the largest weekly decrease). The weekly rates for myocardial infarction visits were lower during the lockdown only (RR 0.61, 95% CI [0.46, 0.77] for the largest weekly decrease), and there was a compensatory increase in visits following reopening. Ischemic stroke 30-day mortality was increased during the lockdown phase (11.5% pre-coronavirus disease; 12.2% during lockdown; 9.2% during early reopening; and 10.6% during late reopening, P = 0.015).

Conclusion

After an initial reduction in visits for stroke and myocardial infarction, there was a compensatory increase in visits for myocardial infarction. The death rate after ischemic stroke was higher during the lockdown than in other phases.

Cardiovascular Risk Associated With Ibrutinib Use in Chronic Lymphocytic Leukemia: A Population-Based Cohort Study

PURPOSE

Ibrutinib reduces mortality in chronic lymphocytic leukemia (CLL). It increases the risk of atrial fibrillation (AF) and bleeding and there are concerns about heart failure (HF) and central nervous system ischemic events. The magnitude of these risks remains poorly quantified.

METHODS

Using linked administrative databases, we conducted a population-based cohort study of Ontario patients who were treated for CLL diagnosed between 2007 and 2019. We matched ibrutinib-treated patients with controls treated with chemotherapy but unexposed to ibrutinib on prior AF, age ≥ 66 years, anticoagulant exposure, and propensity for receiving ibrutinib. Study outcomes were AF-related health care contact, hospital-diagnosed bleeding, new diagnoses of HF, and hospitalizations for stroke and acute myocardial infarction (AMI). The cumulative incidence function was used to estimate absolute risks. We used cause-specific regression to study the association of ibrutinib with bleeding rates, while adjusting for anticoagulation as a time-varying covariate.

RESULTS

We matched 778 pairs of ibrutinib-treated and unexposed patients with CLL (N = 1,556). The 3-year incidence of AF-related health care contact was 22.7% (95% CI, 19.0 to 26.6) in ibrutinib-treated patients and 11.7% (95% CI, 9.0 to 14.8) in controls. The 3-year risk of hospital-diagnosed bleeding was 8.8% (95% CI, 6.5 to 11.7) in ibrutinib-treated patients and 3.1% (95% CI, 1.9 to 4.6) in controls. Ibrutinib-treated patients were more likely to start anticoagulation after the index date. After adjusting for anticoagulation as a time-varying covariate, ibrutinib remained positively associated with bleeding (HR, 2.58; 95% CI, 1.76 to 3.78). The 3-year risk of HF was 7.7% (95% CI, 5.4 to 10.6%) in ibrutinib-treated patients and 3.6% (95% CI, 2.2 to 5.4) in controls. There was no significant difference in the risk of ischemic stroke or AMI.

CONCLUSION

Ibrutinib is associated with higher risk of AF, bleeding, and HF, but not AMI or stroke.

Application of Machine Learning Techniques to Identify Data Reliability and Factors Affecting Outcome After Stroke Using Electronic Administrative Records

Aim: To use available electronic administrative records to identify data reliability, predict discharge destination, and identify risk factors associated with specific outcomes following hospital admission with stroke, compared to stroke specific clinical factors, using machine learning techniques. Method: The study included 2,531 patients having at least one admission with a confirmed diagnosis of stroke, collected from a regional hospital in Australia within 2009-2013. Using machine learning (penalized regression with Lasso) techniques, patients having their index admission between June 2009 and July 2012 were used to derive predictive models, and patients having their index admission between July 2012 and June 2013 were used for validation. Three different stroke types [intracerebral hemorrhage (ICH), ischemic stroke, transient ischemic attack (TIA)] were considered and five different comparison outcome settings were considered. Our electronic administrative record based predictive model was compared with a predictive model composed of "baseline" clinical features, more specific for stroke, such as age, gender, smoking habits, co-morbidities (high cholesterol, hypertension, atrial fibrillation, and ischemic heart disease), types of imaging done (CT scan, MRI, etc.), and occurrence of in-hospital pneumonia. Risk factors associated with likelihood of negative outcomes were identified. Results: The data was highly reliable at predicting discharge to rehabilitation and all other outcomes vs. death for ICH (AUC 0.85 and 0.825, respectively), all discharge outcomes except home vs. rehabilitation for ischemic stroke, and discharge home vs. others and home vs. rehabilitation for TIA (AUC 0.948 and 0.873, respectively). Electronic health record data appeared to provide improved prediction of outcomes over stroke specific clinical factors from the machine learning models. Common risk factors associated with a negative impact on expected outcomes appeared clinically intuitive, and included older age groups, prior ventilatory support, urinary incontinence, need for imaging, and need for allied health input. Conclusion: Electronic administrative records from this cohort produced reliable outcome prediction and identified clinically appropriate factors negatively impacting most outcome variables following hospital admission with stroke. This presents a means of future identification of modifiable factors associated with patient discharge destination. This may potentially aid in patient selection for certain interventions and aid in better patient and clinician education regarding expected discharge outcomes.

Association of Neighborhood-Level Material Deprivation With Health Care Costs and Outcome After Stroke

BACKGROUND AND OBJECTIVES

To determine the association between material deprivation and direct health care costs and clinical outcomes following stroke in the context of a publicly funded universal health care system.

METHODS

In this population-based cohort study of patients with ischemic and hemorrhagic stroke admitted to the hospital between 2008 and 2017 in Ontario, Canada, we used linked administrative data to identify the cohort, predictor variables, and outcomes. The exposure was a 5-level neighborhood material deprivation index. The primary outcome was direct health care costs incurred by the public payer in the first year. Secondary outcomes were death and admission to long-term care.

RESULTS

Among 90,289 patients with stroke, the mean (SD) per-person costs increased with increasing material deprivation, from $50,602 ($55,582) in the least deprived quintile to $56,292 ($59,721) in the most deprived quintile (unadjusted relative cost ratio and 95% confidence interval 1.11 [1.08, 1.13] and adjusted relative cost ratio 1.07 [1.05, 1.10] for least compared to most deprived quintile). People in the most deprived quintile had higher mortality within 1 year compared to the least deprived quintile (adjusted hazard ratio [HR] 1.07 [1.03, 1.12]) as well as within 3 years (adjusted HR 1.09 [1.05, 1.13]). Admission to long-term care increased incrementally with material deprivation and those in the most deprived quintile had an adjusted HR of 1.33 (1.24, 1.43) compared to those in the least deprived quintile.

DISCUSSION

Material deprivation is a risk factor for increased costs and poor outcomes after stroke. Interventions targeting health inequities due to social determinants of health are needed.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that the neighborhood-level material deprivation predicts direct health care costs.

Assessment of Stimulant Use and Cardiovascular Event Risks Among Older Adults

IMPORTANCE

Use of stimulants continues to increase among older adults for a variety of indications. An association between stimulant use and increased risk of cardiovascular (CV) events has been established among children and young adults, but few studies have explored the risk of CV events among older patients, a group with increased baseline risk.

OBJECTIVE

To evaluate the association between stimulant use and risk of CV events among older adults.

DESIGN, SETTING, AND PARTICIPANTS

This propensity score-matched cohort study, with 4 nonusers per 1 user, was conducted from July 1, 2017, to June 27, 2019, using data from population-based health care databases from Ontario, Canada, from January 1, 2002, to December 31, 2016. Included individuals were outpatients aged 66 years or older.

EXPOSURES

Initiation of a prescription stimulant.

MAIN OUTCOMES AND MEASURES

The primary outcome was a CV event, defined as a composite of emergency department visit or hospitalization for myocardial infarction, stroke or transient ischemic attack (TIA), or ventricular arrhythmia. Risk of CV event was assessed at 30 days, 180 days, and 365 days after initiation of stimulants from Cox proportional hazard models. A secondary analysis assessed each component of the primary outcome separately.

RESULTS

Among 6457 older adults who initiated a prescription stimulant (ie, the exposed group) and 24 853 older adults who did not initiate such treatment (ie, the unexposed group), the distribution of baseline patient characteristics was well balanced after matching (sex: 3173 [49.1%] men vs 12 112 [48.7%] men; standardized difference, 0.01; median [IQR] age: 74 [69-80] years vs 74 [69-80] years; standardized difference, 0.01). Within this cohort, there were 932 CV events during the 365-day follow-up (5.11 events per 100 person-years among individuals who initiated stimulants). In the primary analysis, stimulant initiation was associated with increased risk of CV events at 30 days (hazard ratio [HR], 1.4; 95% CI, 1.1-1.8) but not at 180 days (HR, 1.2; 95% CI, 0.9-1.6) or 365 days (HR, 1.0; 95% CI, 0.6 to 1.8). In the secondary analysis, stimulant initiation was associated with increased risk of ventricular arrhythmias (HR, 3.0; 95% CI, 1.1-8.7) and stroke or TIA (HR, 1.6; 95% CI, 1.1-2.1) at 30 days.

CONCLUSIONS AND RELEVANCE

This cohort study found that stimulant use was associated with an early increase in CV events among older adults with no association for long-term use.

Incidence of Stroke in Immigrants to Canada: A Province-wide Retrospective Analysis

BACKGROUND AND OBJECTIVES

To evaluate the association between immigration status and stroke incidence.

METHODS

We conducted a retrospective cohort study of 8 million adults (15% immigrants) residing in Ontario, Canada, on January 1, 2003, with no history of stroke or TIA. Participants were followed up until March 31, 2018, to identify incident stroke or TIA, defined as hospitalization or emergency room visit. We calculated adjusted hazard ratios (HRs) of stroke or TIA in immigrants compared to long-term residents using cause-specific hazard models, adjusting for demographics and comorbid conditions. We evaluated whether the association varied by age, stroke type, or country of origin of immigrants.

RESULTS

During 109 million person-years of follow-up, we observed 235,336 incident stroke or TIA events. Compared to long-term residents, immigrants had a lower rate of stroke or TIA (10.9 vs 23.4 per 10,000 person-years, HR 0.67, 95% confidence interval [CI] 0.66-0.68). This was true across all age groups and stroke types, with an HR in immigrants vs long-term residents for ischemic stroke of 0.71 (95% CI 0.69-0.72), for intracerebral hemorrhage of 0.89 (95% CI 0.85-0.93), for subarachnoid hemorrhage of 0.85 (95% CI 0.81-0.91), and for TIA of 0.53 (95% CI 0.51-0.54). The magnitude of the reduction in stroke risk associated with immigration status was less pronounced in immigrants from the Caribbean (HR 0.95, 95% CI 0.91-1.00), Latin America (HR 0.85, 95% CI 0.82-0.91), and Africa (HR 0.80, 95% CI 0.74-0.85) than in those from other world regions.

DISCUSSION

Immigrants have a lower rate of stroke or TIA than long-term residents with variation by age, stroke type, and country of origin. This knowledge may be useful for developing targeted primary stroke prevention strategies.

Association Between Physical Activity and Mortality Among Community-Dwelling Stroke Survivors

BACKGROUND AND OBJECTIVE

To determine the relationship between physical activity (PA) and mortality in community-dwelling stroke survivors.

METHODS

The Canadian Community Health Survey was used to obtain self-reported PA across 4 survey years and was linked to administrative databases to obtain prior diagnosis of stroke and subsequent all-cause mortality. PA was measured as metabolic equivalents (METs) per week and meeting minimal PA guidelines was defined as 10 MET-h/wk. Cox proportional hazard regression models and restricted cubic splines were used to determine the relationship between PA and all-cause mortality in respondents with prior stroke and controls, adjusting for sociodemographic factors, comorbidities, and functional health status.

RESULTS

The cohort included 895 respondents with prior stroke and 97,805 controls. Adhering to PA guidelines was associated with lower hazard of death for those with prior stroke (adjusted hazard ratio [aHR] 0.46, 95% confidence interval [CI] 0.29-0.73) and controls (aHR 0.69, 95% CI 0.62-0.76). There was a strong dose-response relationship in both groups, with a steep early slope and the vast majority of associated risk reduction occurring between 0 and 20 MET-h/wk. In the group of stroke respondents, PA was associated with greater risk reduction in those <75 years of age (aHR 0.21, 95% CI 0.10-0.43) compared to those ≥75 years of age (aHR 0.68, 95% CI 0.42-1.12).

DISCUSSION

PA was associated with lower all-cause mortality in an apparent dose-dependent manner among those with prior stroke, particularly in younger stroke survivors. Our findings support efforts towards reducing barriers to PA and implementation of PA programs for stroke survivors in the community.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that in community-dwelling survivors of stroke, adhering to physical activity guidelines was associated with lower hazard of death.

Maternal cardiovascular disease after twin pregnancies complicated by hypertensive disorders of pregnancy: a population-based cohort study

Background:

People whose singleton pregnancy is affected by hypertensive disorders of pregnancy (HDP) are at risk of future cardiovascular disease. It is unclear, however, whether this association can be extrapolated to twin pregnancies. We aimed to compare the association between HDP and future cardiovascular disease after twin and singleton pregnancies.

Methods:

We conducted a population-based retrospective cohort study that included nulliparous people in Ontario, Canada, 1992–2017. We compared the future risk of cardiovascular disease among pregnant people from the following 4 groups: those who delivered a singleton without HDP (referent) and with HDP, and those who delivered twins either with or without HDP.

Results:

The populations of the 4 groups were as follows: 1 431 651 pregnant people in the singleton birth without HDP group; 98 631 singleton birth with HDP; 21 046 twin birth without HDP; and 4283 twin birth with HDP. The median duration of follow-up was 13 (interquartile range 7–20) years. The incidence rate of cardiovascular disease was lowest among those with a singleton or twin birth without HDP (0.72 and 0.74 per 1000 person-years, respectively). Compared with people with a singleton birth without HDP, the risk of cardiovascular disease was highest among those with a singleton birth and HDP (1.47 per 1000 person-years; adjusted hazard ratio [HR] 1.81 [95% confidence interval (CI) 1.72–1.90]), followed by people with a twin pregnancy and HDP (1.07 per 1000 person-years; adjusted HR 1.36 [95% CI 1.04–1.77]). The risk of the primary outcome after a twin pregnancy with HDP was lower than that after a singleton pregnancy with HDP (adjusted HR 0.74 [95% CI 0.57–0.97]), when compared directly.

Interpretation:

In a twin pregnancy, HDP are weaker risk factors for postpartum cardiovascular disease than in a singleton pregnancy.

Incidence of stroke in the first year after diagnosis of cancer-A protocol for systematic review and meta-analysis

INTRODUCTION

There is an increased risk of stroke in patients with cancer-this risk is particularly heightened around the time of cancer diagnosis, although no studies have systematically quantified this risk in the literature. Patients newly diagnosed with cancer without prior stroke represent a highly susceptible population in whom there is a window of opportunity to study and implement primary prevention strategies. Therefore, the objective of this systematic review and meta-analysis is to identify the cumulative incidence of ischemic and hemorrhagic strokes during the first year after a diagnosis of cancer.

METHODS AND ANALYSIS

MEDLINE, EMBASE, and PubMed will be searched with the assistance from a medical information specialist, from 1980 until present. Eligible studies will include observational studies that have enrolled adult patients newly diagnosed with cancer and report outcomes of stroke during the first year of cancer diagnosis. We will exclude all randomized and non-randomized interventional studies. Data on participant characteristics, study design, baseline characteristics, and outcome characteristics will be extracted. Study quality will be assessed using the Newcastle-Ottawa Scale for cohort studies, and heterogeneity will be assessed using the I2 statistic. Pooled cumulative incidence will be calculated for ischemic and hemorrhagic strokes separately using a random-effects model.

ETHICS AND DISSEMINATION

No formal research ethics approval is necessary as primary data collection will not be done. We will disseminate our findings through scientific conference presentations, peer-reviewed publications, and social media/the press. The findings from this review will inform clinicians and patients regarding the risk of stroke in patients newly diagnosed with cancer by quantifying the cumulative incidence of each subtype of stroke during the first year after a diagnosis of cancer. This represents a window of opportunity to implement prevention strategies in a susceptible population.

REGISTRATION ID WITH OPEN SCIENCE FRAMEWORK

osf.io/ucwy9.

Evaluation of the Risk of Stroke Without Anticoagulation Therapy in Men and Women With Atrial Fibrillation Aged 66 to 74 Years Without Other CHA2DS2-VASc Factors

Importance

There are limited clinical trial data and discrepant recommendations regarding use of anticoagulation therapy in patients with atrial fibrillation (AF) aged 65 to 74 years without other stroke risk factors.

Objectives

To evaluate the risk of stroke without anticoagulation therapy in men and women with AF aged 66 to 74 years without other CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes, stroke, vascular disease, age 65-74 years, female sex) risk factors and examine the association of stroke incidence with patient age.

Design, Setting, and Participants

A population-based retrospective cohort study was conducted using linked administrative databases. The population included 16 351 individuals aged 66 to 74 years who were newly diagnosed with AF in Ontario, Canada, between April 1, 2007, and March 31, 2017. Exclusion criteria included long-term care residence, prior anticoagulation therapy, valvular disease, heart failure, hypertension, diabetes, stroke, and vascular disease. The cumulative incidence function was used to estimate the 1-year incidence of stroke in patients who did not receive anticoagulation therapy. Fine-Gray regression was used to study the association of patient characteristics with stroke incidence and derive estimates of stroke risk at each age. Death was treated as a competing risk and patients were censored if they initiated anticoagulation therapy. Inverse probability of censoring weights was used to account for patient censoring. Data analysis was performed from May 26, 2019, to December 9, 2020.

Exposures

Atrial fibrillation and age.

Main Outcomes and Measures

Hospitalizations for stroke.

Results

Of the 16 351 individuals with AF (median [interquartile range] age, 70 [68-72] years), 8352 (51.1%) were men; 6314 individuals (38.6%) started anticoagulation therapy during follow-up. The overall 1-year stroke incidence among patients who did not receive anticoagulation therapy was 1.1% (95% CI, 1.0%-1.3%) and the incidence of death without stroke was 8.1% (95% CI, 7.7%-8.5%). The incidence of stroke was not significantly associated with sex. The estimated 1-year stroke risk increased with patient age from 66 years (0.7%; 95% CI, 0.5%-0.9%) to 74 years (1.7%; 95% CI, 1.3%-2.1%).

Conclusions and Relevance

The risk of stroke more than doubled in this study as men and women with AF but no other CHA2DS2-VASc risk factors aged from 66 to 74 years. These data suggest that anticoagulation therapy is more likely to benefit older individuals within this group of patients, whereas younger individuals are less likely to gain net clinical benefit from anticoagulation therapy.

Hospitalization for adverse events under abiraterone or enzalutamide exposure in real-world setting: A French population-based study on prostate cancer patients

AIMS

Safety profiles of abiraterone and enzalutamide rely mainly on Phase III clinical trials. Our objective was to estimate the incidence rate ratio (IRR) for certain adverse events leading in real life to hospitalization (atrial fibrillation, acute heart failure, ischaemic heart disease, acute kidney injury [AKI], ischaemic stroke, torsade de pointe/QT interval prolongation, hepatitis and seizure), comparing abiraterone to enzalutamide. We also set out to discuss previously identified safety signals.

METHOD

Using the French National Health Insurance System database, all patients newly exposed to abiraterone or enzalutamide between 2013 and 2017 and followed until 31 December 2018 were targeted. IRRs for each event were estimated using a Poisson model in a sub-population of patients without contraindications or precautions for use for either treatment.

RESULTS

Among 11 534 new users of abiraterone and enzalutamide, AKI (IRR 1.42, 95% CI: 1.01-2.00), liver monitoring suggestive of hepatic damage (IRR 3.06, 95% CI: 2.66-3.53) and atrial fibrillation (IRR 1.12, 95% CI: 1.05-1.19) were significantly more often observed with abiraterone than with enzalutamide.

CONCLUSION

Our study provides knowledge on abiraterone and enzalutamide real-life safety profiles, especially for events leading to hospitalization. Despite several limitations, including the lack of clinical data, the safety signal for AKI under abiraterone is in line with results of an analysis of the French pharmacovigilance database, which requires further specific investigations. Enlightening the clinicians' therapeutic choices for patients treated for prostate cancer, our study should lead to clinicians being cautious in the use of abiraterone.

Sex differences in the outcomes of adults admitted to inpatient rehabilitation after stroke

INTRODUCTION

Several differences have been reported between male and female patients with stroke in clinical and sociodemographic features, treatment, and outcomes. Potential effects in the inpatient rehabilitation population are unclear.

OBJECTIVE

To evaluate the differences between male and female patients in discharge functional status, length of stay, and discharge home after inpatient rehabilitation for stroke.

DESIGN

Retrospective, population-based cohort study.

SETTING

Inpatient rehabilitation centers in Ontario, Canada.

PARTICIPANTS

Male (N = 10,684) and female (N = 9459) patients discharged from acute care between September 1, 2012 and August 31, 2017, with a diagnosis of stroke and subsequently admitted to inpatient rehabilitation.

EXPOSURE VARIABLE

Female sex.

MAIN OUTCOME MEASURES

Discharge Functional Independence Measure (FIM) score, length of stay, and discharge home.

RESULTS

Female patients had a lower functional status at discharge (mean FIM score 94.1 vs. 97.8, p < .001) and a lower proportion were discharged home (81.1% vs. 82.9%, p = .001). Female and male patients had similar rehabilitation length of stay (mean 31.8 vs. 31.7 days, p = .90). In the adjusted analyses, there was no difference in discharge functional status between male and female patients (FIM score β -.20 [95% confidence interval [CI] -0.64 to 0.25]). Female patients had a mean length of stay 2% shorter (0.98 [95% CI 0.96-0.99]) and a higher odds of discharge home (odds ratio [OR] 1.14 [95% CI 1.05-1.24]).

CONCLUSIONS

There were no clinically significant sex differences in outcomes after inpatient rehabilitation for stroke. Observed sex disparities in the general stroke population may not be directly applicable to individuals undergoing inpatient rehabilitation.

Choice of time-scale in time-to-event analysis: evaluating age-dependent associations

PURPOSE

To compare hazard ratios obtained by using time on study (conventional) versus biological age as the time-scale in survival analyses for a known age-dependent association between an exposure and outcome.

METHODS

We conducted a retrospective cohort study of 9 million people in Ontario, Canada who were followed from 2003 to 2018 to identify incident ischemic stroke using linked administrative health data. Using cause-specific hazards models, we calculated hazard ratios (HR) of ischemic stroke in women compared to men using the two different time scales. By using piecewise estimates and interaction terms, we evaluate the effect of sex on stroke incidence across age groups.

RESULTS

In unadjusted analyses, the reduction in the hazard of ischemic stroke in women compared to men was greater with age as time-scale (HR 0.77; 0.76-0.78) compared to conventional time-scale (HR 0.93; 0.92-0.93); however, the estimates were similar (HR 0.78 with age vs. 0.77 with conventional) in multivariable adjusted analyses. The estimates obtained by two methods across different age groups varied modestly, except in those under 30 years (HR 1.47; 1.19-1.83 with age vs. 1.08; 0.99-1.17 with conventional).

CONCLUSIONS

When evaluating age-dependent association between an exposure and outcome, estimates of association vary based on the time-scale used in survival analysis, requiring thoughtful consideration.

A Digital Twins Machine Learning Model for Forecasting Disease Progression in Stroke Patients

Background: Machine learning methods have been developed to predict the likelihood of a given event or classify patients into two or more diagnostic categories. Digital twin models, which forecast entire trajectories of patient health data, have potential applications in clinical trials and patient management. Methods: In this study, we apply a digital twin model based on a variational autoencoder to a population of patients who went on to experience an ischemic stroke. The digital twin’s ability to model patient clinical features was assessed with regard to its ability to forecast clinical measurement trajectories leading up to the onset of the acute medical event and beyond using International Classification of Diseases (ICD) codes for ischemic stroke and lab values as inputs. Results: The simulated patient trajectories were virtually indistinguishable from real patient data, with similar feature means, standard deviations, inter-feature correlations, and covariance structures on a withheld test set. A logistic regression adversary model was unable to distinguish between the real and simulated data area under the receiver operating characteristic (ROC) curve (AUCadversary = 0.51). Conclusion: Through accurate projection of patient trajectories, this model may help inform clinical decision making or provide virtual control arms for efficient clinical trials.

Systematic Review and Meta-Analysis of Diagnostic Agreement in Suspected TIA

Objective

To determine the interrater variability for TIA diagnostic agreement among expert clinicians (neurologists/stroke physicians), administrative data, and nonspecialists.

Methods

We performed a meta-analysis of studies from January 1984 to January 2019 using MEDLINE, EMBASE, and PubMed. Two reviewers independently screened for eligible studies and extracted interrater variability measurements using Cohen's kappa scores to assess diagnostic agreement.

Results

Nineteen original studies consisting of 19,421 patients were included. Expert clinicians demonstrate good agreement for TIA diagnosis (κ = 0.71, 95% confidence interval [CI] = 0.62-0.81). Interrater variability between clinicians' TIA diagnosis and administrative data also demonstrated good agreement (κ = 0.68, 95% CI = 0.62-0.74). There was moderate agreement (κ = 0.41, 95% CI = 0.22-0.61) between referring clinicians and clinicians at TIA clinics receiving the referrals. Sixty percent of 748 patient referrals to TIA clinics were TIA mimics.

Conclusions

Overall agreement between expert clinicians was good for TIA diagnosis, although variation still existed for a sizeable proportion of cases. Diagnostic agreement for TIA decreased among nonspecialists. The substantial number of patients being referred to TIA clinics with other (often neurologic) diagnoses was large, suggesting that clinicians, who are proficient in managing TIAs and their mimics, should run TIA clinics.

Disparities in diagnosis of cerebral amyloid angiopathy based on hospital characteristics

Cerebral amyloid angiopathy (CAA) categorized as a cerebral small vessel disease can cause lobar intracerebral hemorrhage (ICH), convexity subarachnoid hemorrhage (SAH) and ischemic stroke (IS). The purpose of this study was to evaluate the differences in the diagnosis of CAA based on hospital characteristics and to assess the discharge outcomes of patients with CAA admitted for IS, ICH and SAH. Adult patients admitted with secondary diagnosis of CAA were identified in National Inpatient Sample in 2016 and 2017. Multivariable logistic regression analysis was performed to evaluate outcomes. A total of 16,040 patients had a secondary diagnosis of CAA. Among CAA patients, 1810 (11.3%) patients were admitted for IS, 4765 (29.7%) for ICH and 490 (3.1%) for SAH. Diagnosis of CAA was five-fold higher among patients admitted to urban teaching hospitals (aOR = 5.4;95% CI = 4.1-7.2) compared to rural hospitals and two-fold higher in large bed size hospitals (aOR = 2.3;95% CI = 2.0-2.7) compared to small bed size hospitals. Compared to non-CAA group, patients with history of CAA had lower odds of in-hospital mortality among patients admitted for ICH (10% vs 23%, aOR = 0.35; 95%CI = 0.27-0.44) and SAH (6% vs 19%, aOR = 0.24; 95%CI = 0.10-0.55); and higher odds of discharge to home among patients admitted for ICH (17% vs 18%, aOR = 1.27; 95%CI = 1.05-1.53). CAA diagnosis is less common in rural and small bed size hospitals compared to urban and large bedside hospitals, respectively. Patients with CAA admitted for ICH have better discharge outcomes compared to non-CAA patients admitted for ICH.

Levothyroxine dose and risk of atrial fibrillation: A nested case-control study

Contemporary data on the effect of levothyroxine dose on the occurrence of atrial fibrillation (AF) are lacking, particularly in the older population. Our objective was to determine the effect of cumulative levothyroxine exposure on risk of AF and ischemic stroke in older adults.

METHODS

We conducted a population-based observational study using health care databases from Ontario, Canada. We identified adults aged ≥66 years without a history of AF who filled at least 1 levothyroxine prescription between April 1, 2007, and March 31, 2016. Cases were defined as cohort members who had incident AF (emergency room visit or hospitalization) between the date of first levothyroxine prescription and December 31, 2017. Index date was date of AF. Cases were matched with up to 5 controls without AF on the same index date. Secondary outcome was ischemic stroke. Cumulative levothyroxine exposure was estimated based on total milligrams of levothyroxine dispensed in the year prior to index date. Using nested case-control approach, we compared outcomes between older adults who received high (≥0.125 mg/d), medium (0.075-0.125 mg/d), or low (0-0.075 mg/d) cumulative levothyroxine dose. We compared outcomes between current, recent past, and remote past levothyroxine use.

RESULTS

Of 183,360 older adults treated with levothyroxine (mean age 82 years; 72% women), 30,560 (16.1%) had an episode of AF. Compared to low levothyroxine exposure, high and medium exposure was associated with significantly increased risk of AF after adjustment for covariates (adjusted odds ratio [aOR] 1.29, 95% CI 1.23-1.35; aOR 1.08, 95% CI 1.04-1.11; respectively). No association was observed between levothyroxine exposure and ischemic stroke. Compared with current levothyroxine use, older adults with remote levothyroxine use had lower risks of AF (aOR 0.56, 95% CI 0.52-0.59) and ischemic stroke (aOR 0.61, 95% CI 0.56-0.67).

CONCLUSIONS

Among older persons treated with levothyroxine, levothyroxine at doses >0.075 mg/d is associated with an increased risk of AF compared to lower exposure.

Stroke Incidence by Sex Across the Lifespan

BACKGROUND AND PURPOSE

We evaluated the influence of age on the association between sex and the incidence of stroke or transient ischemic attack (TIA) using a population-based cohort from Ontario, Canada.

METHODS

We followed a cohort of adults (≥18 years) without prior stroke from January 1, 2003 (cohort start date) to March 31, 2018, to identify incident events. We calculated hazard ratios (HRs), in women compared to men, of incident stroke or TIA, adjusted for demographics and comorbidities, overall and stratified by stroke type. We calculated piecewise adjusted HRs for each decade of age to evaluate the effect of age on sex differences in stroke incidence.

RESULTS

We followed 9.2 million adults for a median of 15 years and observed 280,197 incident stroke or TIA events. Compared with men, women had an overall lower adjusted hazard of stroke or TIA (HR, 0.82 [95% CI, 0.82-0.83]), with similar findings across all stroke types except for subarachnoid hemorrhage (HR, 1.29 [95% CI, 1.24-1.33]). We found a U-shaped association between age and sex differences in the incidence of stroke or TIA: compared with men, the hazard of stroke was higher in women among those aged ≤30 years (HR, 1.26 [95% CI, 1.10-1.45]), lower among those between ages 40 and 80 years (eg, age 50-59, HR, 0.69 [95% CI, 0.68-0.70]), and similar among those aged ≥80 years (HR, 0.99 [95% CI, 0.98-1.01]).

CONCLUSIONS

Overall, women have a lower hazard of stroke than men, but this association varies by age and across stroke types. Recognition of age-sex variations in stroke incidence can help guide prevention efforts to reduce stroke incidence in both men and women.

Factors Associated with Stroke Coding Quality: A Comparison of Registry and Administrative Data

BACKGROUND

The International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Australian Modification (ICD-10-AM) codes are commonly used to identify patients with diseases or clinical conditions for epidemiological research. We aimed to determine the diagnostic agreement and factors associated with a clinician-assigned stroke diagnosis in a national registry and the ICD-10-AM codes recorded in government-held administrative data.

MATERIALS AND METHODS

Data from 39 hospitals (2009-2013) participating in the Australian Stroke Clinical Registry (AuSCR) were linked and merged with person-level administrative data. The AuSCR clinician-assigned stroke diagnosis was the reference standard. Concordance was defined as agreement between the clinician-assigned diagnosis and the ICD-10-AM codes for acute stroke or transient ischemic attack (TIA) (ICD-10-AM codes: I61-I64, G45.9). Multivariable logistic regression was undertaken to assess factors associated with coded diagnostic concordance.

RESULTS

A total of 14,716 patient admissions were included (46% female, 63% ischemic, 14% intracerebral hemorrhage [ICH], 18% TIA and 5% unspecified stroke based on the reference standard). Principal ICD-10-AM code concordance was ICH: 76.7%; ischemic stroke: 72.2%; TIA: 80.2%; unspecified stroke: 50.8%. Factors associated with a greater odds of ischemic stroke concordance included: treatment in a stroke unit (adjusted Odds Ratio, aOR:1.58; 95% confidence interval (CI) 1.37, 1.82); length of stay >4 days (aOR:1.30; 95% CI 1.17, 1.45); and discharge destination other than home (Residential care aOR:1.57; 95% CI 1.24, 1.96; Inpatient rehabilitation aOR:1.63; 95% CI 1.43, 1.86).

CONCLUSIONS

Diagnostic concordance varied based on stroke type. Future research to improve the quality of coding for stroke should focus on patients not treated in stroke units or with shorter lengths of stay where documentation in medical records may be limited.

Strategy for reliable identification of ischaemic stroke, thrombolytics and thrombectomy in large administrative databases

Background

Administrative data are frequently used in stroke research. Ensuring accurate identification of patients who had an ischaemic stroke, and those receiving thrombolysis and endovascular thrombectomy (EVT) is critical to ensure representativeness and generalisability. We examined differences in patient samples based on mode of identification, and propose a strategy for future patient and procedure identification in large administrative databases.

Methods

We used non-public administrative data from the state of California to identify all patients who had an ischaemic stroke discharged from an emergency department (ED) or inpatient hospitalisation from 2010 to 2017 based on International Classification of Disease (ICD-9) (2010–2015), ICD-10 (2015–2017) and Medicare Severity-Diagnosis-related Group (MS-DRG) discharge codes. We identified patients with interhospital transfers, patients receiving thrombolytics and patients treated with EVT based on ICD, Current Procedural Terminology (CPT) and MS-DRG codes. We determined what proportion of these transfers and procedures would have been identified with ICD versus MS-DRG discharge codes.

Results

Of 365 099 ischaemic stroke encounters, most (87.70%) had both a stroke-related ICD-9 or ICD-10 code and stroke-related MS-DRG code; 12.28% had only an ICD-9 or ICD-10 code and 0.02% had only an MS-DRG code. Nearly all transfers (99.99%) were identified using ICD codes. We identified 32 433 thrombolytic-treated patients (8.9% of total) using ICD, CPT and MS-DRG codes; the combination of ICD and CPT codes identified nearly all (98%). We identified 7691 patients treated with EVT (2.1% of total) using ICD and MS-DRG codes; both MS-DRG and ICD-9/ICD-10 codes were necessary because ICD codes alone missed 13.2% of EVTs. CPT codes only pertain to outpatient/ED patients and are not useful for EVT identification.

Conclusions

ICD-9/ICD-10 diagnosis codes capture nearly all ischaemic stroke encounters and transfers, while the combination of ICD-9/ICD-10 and CPT codes are adequate for identifying thrombolytic treatment in administrative datasets. However, MS-DRG codes are necessary in addition to ICD codes for identifying EVT, likely due to favourable reimbursement for EVT-related MS-DRG codes incentivising accurate coding.