Huey Juan Lin

Get With The Guidelines-Stroke Performance Indicators: Surveillance of Stroke Care in the Taiwan Stroke Registry: Get With The Guidelines-Stroke in Taiwan

Background— Stroke is a leading cause of death around the world. Improving the quality of stroke care is a global priority, despite the diverse healthcare economies across nations. The American Heart Association/American Stroke Association Get With the Guidelines-Stroke program (GWTG-Stroke) has improved the quality of stroke care in 790 US academic and community hospitals, with broad implications for the rest of the country. The generalizability of GWTG-Stroke across national and economic boundaries remains to be tested. The Taiwan Stroke Registry, with 30 599 stroke admissions between 2006 and 2008, was used to assess the applicability of GWTG-Stroke in Taiwan, which spends ≈1/10 of what the United States does in medical costs per new or recurrent stroke. Methods and Results— Taiwan Stroke Registry, sponsored by the Taiwan Department of Health, engages 39 academic and community hospitals and covers the entire country with 4 steps of quality control to ensure the reliability of entered data. Five GWTG-Stroke performance measures and 1 safety indicator are applicable to assess Taiwan Stroke Registry quality of stroke care. Demographic and outcome figures are comparable between GWTG-Stroke and Taiwan Stroke Registry. Two indicators (early and discharge antithrombotics) are close to GWTG-Stroke standards, while 3 other indicators (intravenous tissue plasminogen activator, anticoagulation for atrial fibrillation, lipid-lowering medication) and 1 safety indicator fall behind. Preliminary analysis shows that compliance with selected GWTG-Stroke guidelines is associated with better outcomes. Conclusions— Results suggest that GWTG-Stroke performance measures, with modification for ethnic factors, can become global standards across national and economic boundaries for assessing and improving quality of stroke care and outcomes. GWTG-Stroke can be incorporated into ongoing stroke registries across nations.

Association between genetic variant on chromosome 12p13 and stroke survival and recurrence: a one year prospective study in Taiwan

BackgroundThe association between ischemic stroke and 2 single nucleotide polymorphisms (SNPs) on chromosome 12p13, rs12425791 and rs11833579 appears inconsistent across different samples. These SNPs are close to the ninjurin2 gene which may alter the risk of stroke by affecting brain response to ischemic injury. The purpose of this study was to investigate the association between these two SNPs and ischemic stroke risk, as well as prognostic outcomes in a Taiwanese sample.MethodsWe examined the relations of these two SNPs to the odds of new-onset ischemic stroke, ischemic stroke subtypes, and to the one year risk of stroke-related death or recurrent stroke following initial stroke in a case-control study. A total of 765 consecutive patients who had first-ever ischemic stroke were compared to 977 stroke-free, age-matched controls. SNPs were genotyped by Taqman fluorescent allelic discrimination assay. The association between ischemic stroke and SNPs were analyzed by multivariate logistic regression. Cox proportional hazard model was used to assess the effect of individual SNPs on stroke-related mortality or recurrent stroke.ResultsThere was no significant association between SNP rs12425791 and rs11833579 and ischemic stroke after multiple testing corrections. However, the marginal significant association was observed between SNP rs12425791 and large artery atherosclerosis under recessive model (OR, 2.30; 95%CI, 1.22-4.34; q-value = 0.062). Among the 765 ischemic stroke patients, 59 died or developed a recurrent stroke. After adjustment for age, sex, vascular risk factors and baseline stroke severity, Cox proportional hazard analysis indicated that the hazard ratios were 2.76 (95%CI, 1.34-5.68; q-value, 0.02) and 2.15 (95%CI, 1.15-4.02; q-value, 0.03) for individuals with homozygous variant allele of rs12425791 and rs11833579, respectively.ConclusionsThis is a precedent study that found genetic variants of rs12425791 and rs11833579 on chromosome 12p13 are independent predictors of stroke-related mortality or stroke recurrence in patients with incident ischemic stroke in Taiwan. Further study is needed to explore the details of the physiological function and the molecular mechanisms underlying the association of this genetic locus with ischemic stroke.

Comparison of Risk-scoring Systems in Predicting Symptomatic Intracerebral Hemorrhage After Intravenous Thrombolysis

Background and Purpose— Various risk score models have been developed to predict symptomatic intracerebral hemorrhage (SICH) after intravenous thrombolysis for acute ischemic stroke. In this study, we aimed to determine the prediction performance of these risk scores in a Taiwanese population Methods— Prospectively collected data from 4 hospitals were used to calculate probability of SICH with the scores developed by Cucchiara et al, the Hemorrhage After Thrombolysis (HAT) score, the Safe Implementation of Thrombolysis in Stroke-SICH risk score, the Glucose Race Age Sex Pressure Stroke Severity score, and the Stroke Prognostication using Age and National Institutes of Health Stroke Scale-100 index. We used logistic regression to evaluate the effectiveness of each risk model in predicting SICH and the c statistic to assess performance. Results— A total of 548 patients were included. The rates of SICH were 7.3% by the National Institute of Neurological Diseases and Stroke definition, 5.3% by the European-Australasian Cooperative Acute Stroke Study II definition, and 3.5% by the Safe Implementation of Thrombolysis in Stroke-Monitoring Study definition. The Cucchiara score, the HAT score, and the Safe Implementation of Thrombolysis in Stroke-SICH risk score were significant predictors of SICH for all 3 definitions, whereas the Glucose Race Age Sex Pressure Stroke Severity score and the Stroke Prognostication using Age and National Institutes of Health Stroke Scale-100 index predicted well only for 1 or 2 definitions of SICH. The c statistic was highest for the HAT score (range, 0.69–0.73) across the definitions of SICH. Conclusions— The Cucchiara score, the HAT score, and the Safe Implementation of Thrombolysis in Stroke-SICH risk score predicted SICH reasonably well regardless of which SICH definition was used. However, only the HAT score had an acceptable discriminatory ability.

Developing a stroke severity index based on administrative data was feasible using data mining techniques

OBJECTIVESnCase-mix adjustment is difficult for stroke outcome studies using administrative data. However, relevant prescription, laboratory, procedure, and service claims might be surrogates for stroke severity. This study proposes a method for developing a stroke severity index (SSI) by using administrative data.nnnSTUDY DESIGN AND SETTINGnWe identified 3,577 patients with acute ischemic stroke from a hospital-based registry and analyzed claims data with plenty of features. Stroke severity was measured using the National Institutes of Health Stroke Scale (NIHSS). We used two data mining methods and conventional multiple linear regression (MLR) to develop prediction models, comparing the model performance according to the Pearson correlation coefficient between the SSI and the NIHSS. We validated these models in four independent cohorts by using hospital-based registry data linked to a nationwide administrative database.nnnRESULTSnWe identified seven predictive features and developed three models. The k-nearest neighbor model (correlation coefficient, 0.743; 95% confidence interval: 0.737, 0.749) performed slightly better than the MLR model (0.742; 0.736, 0.747), followed by the regression tree model (0.737; 0.731, 0.742). In the validation cohorts, the correlation coefficients were between 0.677 and 0.725 for all three models.nnnCONCLUSIONnThe claims-based SSI enables adjusting for disease severity in stroke studies using administrative data.

Validation of algorithms to identify stroke risk factors in patients with acute ischemic stroke, transient ischemic attack, or intracerebral hemorrhage in an administrative claims database.

BACKGROUNDnStroke patients have a high risk for recurrence, which is positively correlated with the number of risk factors. The assessment of risk factors is essential in both stroke outcomes research and the surveillance of stroke burden. However, methods for assessment of risk factors using claims data are not well developed.nnnMETHODSnWe enrolled 6469 patients with acute ischemic stroke, transient ischemic attack, or intracerebral hemorrhage from hospital-based stroke registries, which were linked with Taiwans National Health Insurance (NHI) claims database. We developed algorithms using diagnosis codes and prescription data to identify stroke risk factors including hypertension, diabetes, hyperlipidemia, atrial fibrillation (AF), and coronary artery disease (CAD) in the claims database using registry data as reference standard. We estimated the kappa statistics to quantify the agreement of information on the risk factors between claims and registry data.nnnRESULTSnThe prevalence of risk factors in the registries was hypertension 77.0%, diabetes 39.1%, hyperlipidemia 55.6%, AF 10.1%, and CAD 10.9%. The highest kappa statistics were 0.552 (95% confidence interval 0.528-0.577) for hypertension, 0.861 (0.836-0.885) for diabetes, 0.572 (0.549-0.596) for hyperlipidemia, 0.687 (0.663-0.712) for AF, and 0.480 (0.455-0.504) for CAD. Algorithms based on diagnosis codes alone could achieve moderate to high agreement in identifying the selected risk factors, whereas prescription data helped improve identification of hyperlipidemia.nnnCONCLUSIONSnWe tested various claims-based algorithms to ascertain important risk factors in stroke patients. These validated algorithms are useful for assessing stroke risk factors in future studies using Taiwans NHI claims data.

Validity of a stroke severity index for administrative claims data research: a retrospective cohort study

BackgroundAscertaining stroke severity in claims data-based studies is difficult because clinical information is unavailable. We assessed the predictive validity of a claims-based stroke severity index (SSI) and determined whether it improves case-mix adjustment.MethodsWe analyzed patients with acute ischemic stroke (AIS) from hospital-based stroke registries linked with a nationwide claims database. We estimated the SSI according to patient claims data. Actual stroke severity measured with the National Institutes of Health Stroke Scale (NIHSS) and functional outcomes measured with the modified Rankin Scale (mRS) were retrieved from stroke registries. Predictive validity was tested by correlating SSI with mRS. Logistic regression models were used to predict mortality.ResultsThe SSI correlated with mRS at 3xa0months (Spearman rhou2009=u20090.578; 95xa0% confidence interval [CI], 0.556–0.600), 6xa0months (rhou2009=u20090.551; 95xa0% CI, 0.528–0.574), and 1xa0year (rhou2009=u20090.532; 95xa0% CI 0.504–0.560). Mortality models with the SSI demonstrated superior discrimination to those without. The AUCs of models including the SSI and models with the NIHSS did not differ significantly.ConclusionsThe SSI correlated with functional outcomes after AIS and improved the case-mix adjustment of mortality models. It can act as a valid proxy for stroke severity in claims data-based studies.

Low levels of high-density lipoprotein cholesterol in patients with atherosclerotic stroke: A prospective cohort study

OBJECTIVEnThe purpose of this study was to evaluate the influence of baseline high-density lipoprotein cholesterol (HDL-C) on initial stroke severity and clinical outcomes in acute ischemic stroke.nnnMETHODSnFrom August 2006 through December 2011, patients with acute atherosclerotic ischemic stroke were included. Total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL-C) and HDL-C were checked and National Institutes of Health Stroke Scale (NIHSS) scores were obtained at admission. The primary outcomes were a composite end point of all-cause mortality, recurrent stroke, or occurrence of ischemic heart disease during follow-up.nnnRESULTSnOverall, 3093 subjects (mean age 66.8 years) were included and 675 patients (22%) had low HDL-C (≤35xa0mg/dL) at admission. These patients had higher NIHSS scores. After adjusting for all clinical factors in multivariate logistic analysis, low HDL-C at admission (OR, 1.79, 95% CI, 1.40-2.29) was significantly associated with higher stroke severity (NIHSS scorexa0>xa06). During the follow-up period, 280 patients (9%) developed one of the components of the composite end point, including 76 (11.3%) in patients with low HDL-C and 204 (8.4%) in patients with normal HDL-C at admission (pxa0<xa00.001). In multivariate Cox regression analysis, after adjusting for all clinical factors, low HDL-C at admission (HR, 1.41, 95% CI, 1.02-1.95) was a significant independent predictor of the composite end point.nnnCONCLUSIONSnLow baseline HDL-C (≤35xa0mg/dL) at admission was associated with higher stroke severity and poor clinical outcome during follow-up in patients with atherosclerotic ischemic stroke.

Validation of a novel claims-based stroke severity index in patients with intracerebral hemorrhage

Background Stroke severity is an important outcome predictor for intracerebral hemorrhage (ICH) but is typically unavailable in administrative claims data. We validated a claims-based stroke severity index (SSI) in patients with ICH in Taiwan. Methods Consecutive ICH patients from hospital-based stroke registries were linked with a nationwide claims database. Stroke severity, assessed using the National Institutes of Health Stroke Scale (NIHSS), and functional outcomes, assessed using the modified Rankin Scale (mRS), were obtained from the registries. The SSI was calculated based on billing codes in each patients claims. We assessed two types of criterion-related validity (concurrent validity and predictive validity) by correlating the SSI with the NIHSS and the mRS. Logistic regression models with or without stroke severity as a continuous covariate were fitted to predict mortality at 3, 6, and 12 months. Results The concurrent validity of the SSI was established by its significant correlation with the admission NIHSS (r = 0.731; 95% confidence interval [CI], 0.705–0.755), and the predictive validity was verified by its significant correlations with the 3-month (r = 0.696; 95% CI, 0.665–0.724), 6-month (r = 0.685; 95% CI, 0.653–0.715) and 1-year (r = 0.664; 95% CI, 0.622–0.702) mRS. Mortality models with NIHSS had the highest area under the receiver operating characteristic curve, followed by models with SSI and models without any marker of stroke severity. Conclusions The SSI appears to be a valid proxy for the NIHSS and an effective adjustment for stroke severity in studies of ICH outcome with administrative claims data.

Is renal dysfunction associated with adverse stroke outcome after thrombolytic therapy

Background: Renal dysfunction is a prevalent comorbidity in acute stroke patients requiring thrombolytic therapy. Reports studying the relationship between renal dysfunction and risk of postthrombolytic symptomatic intracerebral hemorrhage (SICH) are contradictory. We aimed to compare the safety and effectiveness of thrombolytic therapy in acute stroke patients with and without renal dysfunction. Methods: Based on the prospective stroke registries of 4 hospitals in Taiwan from 2007-2012, we identified acute stroke patients who received thrombolytic therapy. Clinically significant renal dysfunction was defined as an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2. Renal dysfunction was further defined as stage 3 (30 ≤ eGFR < 60 ml/min/ 1.73 m2), stage 4 (15 ≤ eGFR < 30 ml/min/1.73 m2) and stage 5 (<15 ml/min/1.73 m2). The rates of SICH and poor outcome (defined as modified Rankin scale score ≥4) at 3 months after thrombolytic therapy were compared in patients with and without renal dysfunction. SICH was determined according to the definition of the National Institute of Neurological Disorders and Stroke. Multivariable logistic regression was used to determine the effect of renal dysfunction on outcome. Patients with different stages of renal dysfunction were further analyzed to determine the effect of disease severity on outcome. Results: Of the 657 stroke patients with thrombolysis, 239 (36%) had renal dysfunction, including 212 patients in stage 3, 17 patients in stage 4 and 10 patients in stage 5 of renal dysfunction. Patients with renal dysfunction were older and more likely to have hypertension, ischemic heart disease, congestive heart failure and prior antiplatelet use than those without. There were no differences in SICH (8 vs. 7%, p = 0.580) and poor outcome (41 vs. 39%, p = 0.758) between patients with and without renal dysfunction. After multivariable analysis, renal dysfunction was not associated with SICH (odds ratio: 1.03, 95% confidence interval: 0.55-1.92) and poor outcome. Pretreatment stroke severity was the only factor significantly associated with both SICH and poor outcome at 3 months. When stratifying renal dysfunction into stage 3 and stage ≥4, there was no significant increase in SICH as the severity of renal dysfunction increased after multivariable adjustment. Conclusions: Renal dysfunction did not increase the risk of SICH and poor outcome at 3 months after stroke thrombolysis. Further study comparing directly the risk and benefit of thrombolytic therapy versus no therapy in stroke patients with renal dysfunction is warranted.

Predicting symptomatic intracerebral hemorrhage after intravenous thrombolysis: stroke territory as a potential pitfall.

BACKGROUNDnStroke vascular territories may influence response to thrombolysis, although supporting data are limited. The aim of the study was to test the hypothesis that the current available prediction scores might inaccurately estimate the risk of symptomatic intracerebral hemorrhage (SICH) after intravenous thrombolysis in patients with posterior circulation stroke.nnnMETHODSnWe applied the Safe Implementation of Thrombolysis in Stroke (SITS) SICH risk score to data from four hospital-based stroke registries. Patients were grouped according to anterior or posterior circulation stroke. The main outcome measure was SICH per various definitions. Performance of the risk score was assessed with the c statistic.nnnRESULTSnData of 518 thrombolyzed patients (434 anterior, 84 posterior) were studied. The overall rate of SICH varied from 3.5% to 6.9% depending on the SICH definition. Patients with posterior circulation stroke were less likely to have post-thrombolysis SICH per NINDS (P=0.042), per ECASS II (P=0.013), or any ICH (P=0.001), and their rate of SICH was markedly lower than predicted (1.2% versus 7.1% by the NINDS definition; 0% versus 4.8%, ECASS II; 0% versus 1.6%, SITS-MOST). The SITS SICH risk score shows moderate model discrimination across the SICH definitions, with c statistic ranging from 0.64 to 0.70.nnnCONCLUSIONSnThe risk of SICH after intravenous thrombolysis in patients with posterior circulation stroke was low enough to render the SITS SICH risk score or other similar prediction models unnecessary. Awareness of stroke territory might help clinicians judiciously use the risk assessment models.