Risk of ischemic stroke after discharge from inpatient surgery: Does the type of surgery matter?

OBJECTIVE: Stroke is a well-known and devastating complication during the perioperative period. However, detailed stroke risk profiles within 90 days in patients discharged without stroke after inpatient surgery are not fully understood. Using the case-crossover design, we aimed to evaluate the risk of ischemic stroke in these patients. METHODS: We included adult patients with the first hospitalization for ischemic stroke between 2011 and 2012 from 23 million enrollees in the National Health Insurance Research Database. Admission date of the hospitalization was defined as the case day and exactly 365 days before the admission date as the control day. The exposure was the last hospitalization for surgery within 1-30, 31-60, or 61-90 days (case period) before the case day or similar time intervals (control period) before the control day. Surgical types were grouped based on the International Classification of Diseases procedure codes. We performed conditional logistic regression adjusting for time-varying variables to determine the relationship between surgery and subsequent stroke, and case-time-control analyses to examine whether the results were confounded by the time-trend in surgery. RESULTS: A total of 56596 adult patients (41% female, mean age 69 years) comprised the study population. After adjustment was made for confounding variables, an association between stroke and prior inpatient surgery within 30 days was observed (adjusted odds ratio 1.44; 95% confidence interval 1.29-1.61). Cardiothoracic, vascular, digestive surgery, and musculoskeletal surgery within 30 days independently predicted ischemic stroke in the case-crossover analysis. In the case-time-control analysis, inpatient surgery remained an independent risk factor for ischemic stroke, whereas only cardiothoracic, vascular, and digestive surgery independently predicted ischemic stroke. CONCLUSIONS: Surgery as a whole independently increased the risk of ischemic stroke within 30 days. Among various types of surgery, cardiothoracic, vascular, and digestive surgery significantly increased the risk of ischemic stroke.

Characteristics and outcomes of ischemic stroke in patients with known atrial fibrillation or atrial fibrillation diagnosed after stroke.

BACKGROUND: It is unclear whether ischemic stroke patients with known atrial fibrillation (KAF) had different outcomes than those with atrial fibrillation diagnosed after stroke (AFDAS). We aimed to explore the characteristics and outcomes in ischemic stroke patients with KAF or AFDAS. METHODS: Consecutive patients hospitalized between 2000 and 2012 for first-ever stroke along with atrial fibrillation, either diagnosed before or during the stroke hospitalization, were identified from a nationwide claims database in Taiwan. The outcome of interest was a composite outcome of ischemic stroke, intracranial hemorrhage, or death within one year. Univariable and multivariable Cox regression analyses were used to determine the effect of KAF versus AFDAS on the composite outcome. RESULTS: We identified 1161 patients, of whom 481 (41.4%) had KAF and 680 (58.6%) had AFDAS. Age, sex, and stroke severity were similar between groups. However, patients with KAF had a higher prevalence of underlying heart diseases than those with AFDAS (67.2% versus 39.0%, p<0.001). In univariable analysis, patients with KAF had a higher risk of the composite outcome than those with AFDAS (hazard ratio [HR]: 1.42, 95% confidence interval [CI]: 1.13-1.79, p=0.003). In multivariable analysis, KAF was no longer independently associated with the composite outcome. CONCLUSIONS: As compared to ischemic stroke patients with AFDAS, those with KAF had a higher prevalence of underlying heart diseases. Whether AF was known before or diagnosed after stroke was not an independent predictor of the composite outcome.

Applying natural language processing techniques to develop a task-specific EMR interface for timely stroke thrombolysis: A feasibility study.

OBJECTIVE: To reduce errors in determining eligibility for intravenous thrombolytic therapy (IVT) in stroke patients through use of an enhanced task-specific electronic medical record (EMR) interface powered by natural language processing (NLP) techniques. MATERIALS AND METHODS: The information processing algorithm utilized MetaMap to extract medical concepts from IVT eligibility criteria and expanded the concepts using the Unified Medical Language System Metathesaurus. Concepts identified from clinical notes by MetaMap were compared to those from IVT eligibility criteria. The task-specific EMR interface displays IVT-relevant information by highlighting phrases that contain matched concepts. Clinical usability was assessed with clinicians staffing the acute stroke team by comparing user performance while using the task-specific and the current EMR interfaces. RESULTS: The algorithm identified IVT-relevant concepts with micro-averaged precisions, recalls, and F1 measures of 0.998, 0.812, and 0.895 at the phrase level and of 1, 0.972, and 0.986 at the document level. Users using the task-specific interface achieved a higher accuracy score than those using the current interface (91% versus 80%, p = 0.016) in assessing the IVT eligibility criteria. The completion time between the interfaces was statistically similar (2.46 min versus 1.70 min, p = 0.754). DISCUSSION: Although the information processing algorithm had room for improvement, the task-specific EMR interface significantly reduced errors in assessing IVT eligibility criteria. CONCLUSION: The study findings provide evidence to support an NLP enhanced EMR system to facilitate IVT decision-making by presenting meaningful and timely information to clinicians, thereby offering a new avenue for improvements in acute stroke care.

Prediction of new-onset atrial fibrillation after first-ever ischemic stroke: A comparison of CHADS2, CHA2DS2-VASc and HATCH scores and the added value of stroke severity.

BACKGROUND AND AIMS: Early detection of atrial fibrillation after stroke is important for secondary prevention in stroke patients without known atrial fibrillation (AF). We aimed to compare the performance of CHADS2, CHA2DS2-VASc and HATCH scores in predicting AF detected after stroke (AFDAS) and to test whether adding stroke severity to the risk scores improves predictive performance. METHODS: Adult patients with first ischemic stroke event but without a prior history of AF were retrieved from a nationwide population-based database. We compared C-statistics of CHADS2, CHA2DS2-VASc and HATCH scores for predicting the occurrence of AFDAS during stroke admission (cohort I) and during follow-up after hospital discharge (cohort II). The added value of stroke severity to prediction models was evaluated using C-statistics, net reclassification improvement, and integrated discrimination improvement. RESULTS: Cohort I comprised 13,878 patients and cohort II comprised 12,567 patients. Among them, 806 (5.8%) and 657 (5.2%) were diagnosed with AF, respectively. The CHADS2 score had the lowest C-statistics (0.558 in cohort I and 0.597 in cohort II), whereas the CHA2DS2-VASc score had comparable C-statistics (0.603 and 0.644) to the HATCH score (0.612 and 0.653) in predicting AFDAS. Adding stroke severity to each of the three risk scores significantly increased the model performance. CONCLUSIONS: In stroke patients without known AF, all three risk scores predicted AFDAS during admission and follow-up, but with suboptimal discrimination. Adding stroke severity improved their predictive abilities. These risk scores, when combined with stroke severity, may help prioritize patients for continuous cardiac monitoring in daily practice.

Registry-based stroke research in Taiwan: past and future.

Stroke registries are observational databases focusing on the clinical information and outcomes of stroke patients. They play an important role in the cycle of quality improvement. Registry data are collected from real-world experiences of stroke care and are suitable for measuring quality of care. By exposing inadequacies in performance measures of stroke care, research from stroke registries has changed how we manage stroke patients in Taiwan. With the success of various quality improvement campaigns, mortality from stroke and recurrence of stroke have decreased in the past decade. After the implementation of a nationwide stroke registry, researchers have been creatively expanding how they use and collect registry data for research. Through the use of the nationwide stroke registry as a common data model, researchers from many hospitals have built their own stroke registries with extended data elements to meet the needs of research. In collaboration with information technology professionals, stroke registry systems have changed from web-based, manual submission systems to automated fill-in systems in some hospitals. Furthermore, record linkage between stroke registries and administrative claims databases or other existing databases has widened the utility of registry data in research. Using stroke registry data as the reference standard, researchers have validated several algorithms for ascertaining the diagnosis of stroke and its risk factors from claims data, and have also developed a claims-based index to estimate stroke severity. By making better use of registry data, we believe that we will provide better care to patients with stroke.

Effect of Rehabilitation Intensity on Mortality Risk After Stroke.

OBJECTIVE: To determine the relation between rehabilitation intensity and poststroke mortality. DESIGN: Retrospective cohort study. SETTING: Nationwide claims data. PARTICIPANTS: From Taiwan's National Health Insurance claims databases, patients (N=6737; mean age, 66.9y; 40.3% women) hospitalized between 2001 and 2013 for a first-ever stroke who had mild to moderate stroke and survived the first 90 days of stroke were enrolled. INTERVENTIONS: The intensity of rehabilitation therapy within 90 days after stroke was categorized into low, medium, or high based on the tertile distribution of the number of rehabilitation sessions. MAIN OUTCOME MEASURES: Long-term all-cause mortality. The Cox proportional hazard models with Bonferroni correction were used to assess the association between rehabilitation intensity and mortality, adjusting for age, comorbidities, stroke severity, and other covariates. RESULTS: Patients in the high-intensity group were younger but had a higher burden of comorbidities and greater stroke severity. During follow-up, the high-intensity group was associated with a significantly lower adjusted risk (hazard ratio [HR], .73; 95% confidence interval [CI], .63-.84) of mortality than the low-intensity group, whereas the medium-intensity group carried a similar risk of mortality (HR, 0.94; 95% CI, 0.84-1.06) compared with the low-intensity group. This association was not modified by stroke severity. CONCLUSIONS: Among patients with mild to moderate stroke severity, high-intensity rehabilitation therapy within the first 90 days was associated with a lower mortality risk than low-intensity therapy. Efforts to promote high-intensity rehabilitation therapy for this group of patients with stroke should be encouraged.

Previously undiagnosed risk factors and medication nonadherence are prevalent in young adults with first-ever stroke.

PURPOSE: The incidence of stroke and prevalence of traditional vascular risk factors (VRFs) in young adults (age < 55 y) are both increasing. Young patients tend to be unaware of their VRFs and to have lower medication adherence. We examined how age affects the prevalence of previously undiagnosed VRFs and the extent of medication nonadherence among stroke patients. METHODS: Using Taiwan's National Health Insurance Research Database, we identified consecutive adult patients with first-ever stroke between 2000 and 2013. Diagnosis of hypertension, diabetes, and hyperlipidemia was ascertained using validated methods. We investigated (1) the proportion of patients who had undiagnosed VRFs within 3 years before stroke and (2) the proportion of nonadherence to medications among patients who had a previously diagnosed VRF. RESULTS: Among stroke patients with hypertension (n = 9722), diabetes (n = 4751), and hyperlipidemia (n = 4486), 24.9%, 20.8%, and 55.0%, respectively, had not been diagnosed before stroke, whereas 56.0%, 66.7%, and 32.5%, respectively, had been diagnosed at least 1 year before stroke. The proportions of medication nonadherence were 71.5%, 64.3%, and 88.4% in patients with previously diagnosed hypertension, diabetes, and hyperlipidemia, respectively. In multivariate analysis, younger age was independently associated with undiagnosed hypertension before stroke as well as medication nonadherence in patients with previously diagnosed hypertension or diabetes. CONCLUSIONS: Previously undiagnosed hypertension and nonadherence to treatment of hypertension and diabetes were more prevalent in young adult patients with first-ever stroke in Taiwan. Interventions targeting young people to promote early detection and adequate control of VRFs should be encouraged.

Trends in vascular risk factors, stroke performance measures, and outcomes in patients with first-ever ischemic stroke in Taiwan between 2000 and 2012.

BACKGROUND: With the aging of the population in Taiwan, the financial burden of stroke on the healthcare system is expected to rise. We aimed to investigate the trends in vascular risk factors, adherence to stroke performance measures, and stroke outcomes based on a nationwide representative sample. METHODS: Adult patients hospitalized for first-ever ischemic stroke between 2000 and 2012 were identified from a nationwide administrative database. The study period was divided into 1-year intervals. The Cuzick test and the Cochran-Armitage test were used to determine the significance of changes over time. Trends in stroke outcomes as a function of year were assessed using logistic regression, controlling for age, sex, comorbidity, and stroke severity. RESULTS: A total of 11,462 patients (mean age 67.3years, female 40.9%) were hospitalized. Between 2000 and 2012, the prevalence of hypertension, diabetes mellitus, hyperlipidemia, and atrial fibrillation increased while the prevalence of coronary artery disease decreased. The proportion of patients taking antihypertensive or antidiabetic medication prior to stroke decreased, whereas the proportion of patients taking lipid lowering medication increased. Adherence to the five selected performance measures significantly improved. A significant decreasing trend in the proportion of recurrent stroke or all-cause death within one year was observed regardless of whether adjustment for age, sex, comorbidity, and stroke severity was made. CONCLUSIONS: Despite the rising prevalence of vascular risk factors, improved adherence to stroke performance measures was accompanied by better stroke outcomes.