Characteristics, Performance Measures, and In-Hospital Outcomes of the First One Million Stroke and Transient Ischemic Attack Admissions in Get With The Guidelines-Stroke
Background— Stroke results in substantial death and disability. To address this burden, Get With The Guideline (GWTG)-Stroke was developed to facilitate the measurement, tracking, and improvement in quality of care and outcomes for acute stroke and transient ischemic attack (TIA) patients in the United States.
Methods and Results— We analyzed the characteristics, performance measures, and in-hospital outcomes in the first 1 000 000 acute ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage, and TIA admissions from 1392 hospitals that participated in the GWTG-Stroke Program 2003 to 2009. Patients were 53.5% women, 73.3% white, and with mean age of 70.1±14.9 years. There were 601 599 (60.2%) ischemic strokes, 108 671 (10.9%) intracerebral hemorrhages, 34 945 (3.5%) subarachnoid hemorrhages, 26 977 (2.7%) strokes not classified, and 227 788 (22.8%) TIAs. Performance measures showed small to moderate differences by cerebrovascular event type. In-hospital mortality rate was highest among intracerebral hemorrhage (25.0%) and subarachnoid hemorrhage (20.4%), and intermediate in ischemic stroke (5.5%) patients and lowest among TIA patients (0.3%). Significant improvements over time from 2003 to 2009 in quality of care were observed: all-or-none measure, 44.0% versus 84.3% (+40.3%, P<0.0001). After adjustment for patient and hospital variables, the cumulative adjusted odds ratio for the all-or-none measure over the 6 years was 9.4 (95% confidence interval, 8.3 to 10.6, P<0.0001). Temporal improvements in length of stay and risk-adjusted in-hospital mortality rate (for ischemic stroke and TIA) were also observed.
Conclusions— With more than 1 million patients enrolled, GWTG-Stroke represents an integrated stroke and TIA registry that supports national surveillance, innovative research, and sustained quality improvement efforts facilitating evidence-based stroke/TIA care.
Received November 10, 2009; accepted February 8, 2010.
Each year, more than 795 000 Americans have a stroke and another 200 000 to 500 000 present with a transient ischemic attack (TIA).1 Stroke is the third leading cause of death and a leading cause of disability in the United States.1 The estimated direct and indirect costs of stroke exceed $68.9 billion in 2009.1 Although evidence-based guidelines for stroke and TIA care have been developed along with improved diagnostic and treatment modalities,2,3 there are gaps, variations, and disparities in how these are applied.4–6 Furthermore, many hospitals may not have the systems, organization, staff, and equipment to effectively diagnose, manage, and treat acute stroke patients. To help reduce the nation’s stroke burden, several organizations began to develop and implement registries to measure and track acute stroke care with the intent of motivating improvements in the quality of stroke care.4,7 The Get With The Guidelines (GWTG)-Stroke Program was developed by the American Heart Association/American Stroke Association (AHA/ASA) as a national stroke registry and performance improvement program with the primary goal of improving the quality of care and outcomes for stroke and TIA as well as serve as a scientific resource for new information.7,8
Although several prior studies have described the quality of care and outcomes for patients hospitalized with cerebrovascular events, uncertainty remains about care quality and clinical outcomes for contemporary populations of patients hospitalized with stroke and TIA.4,5,9–12 Previous studies have examined selected patient populations, lacked detailed data on diagnosis and care, and did not always collect complete data on contraindications to recommended therapies.4,5,9–12 Because of its size, national scope, duration, and prospective collection of quality of care data, the GWTG-Stroke Program provides a unique opportunity to analyze presenting characteristics, treatments, quality indicators, and in-hospital outcomes for a very broad cohort of patients hospitalized with stroke and TIA. The objective of this study was to characterize the first 1 million patient hospitalizations entered into the GWTG-Stroke Program and examine differences in demographics, treatments, quality of care, and early clinical outcomes by type of cerebrovascular event in this population.
WHAT IS KNOWN
Stroke results in substantial death and disability. Each year more than 795 000 Americans have a stroke and another 200 000 to 500 000 present with a transient ischemic attack (TIA).
Although evidence-based guidelines for stroke and TIA care have been developed along with improved diagnostic and treatment modalities, there are gaps, variations, and disparities in how these are applied.
The Get With The Guidelines (GWTG)-Stroke Program was developed by the American Heart Association/American Stroke Association as a national stroke registry and performance improvement program with the primary goal of improving the quality of care and outcomes for stroke and TIA as well as serve as a scientific resource for new information.
WHAT THE STUDY ADDS
Among hospitals participating in this very large quality improvement effort with more than 1 million patients enrolled, there were substantial improvements over time in performance measures, overall and for each cerebrovascular event type. Temporal improvements in length of stay and risk-adjusted in-hospital mortality (for ischemic stroke and TIA) were also observed.
This study demonstrates the ongoing value of GWTG-Stroke as an integrated stroke and TIA national registry providing national surveillance, fostering innovative research, and supporting vigorous efforts to improve evidence-based stroke/TIA care and clinical outcomes.
GWTG-Stroke is an ongoing voluntary, continuous registry and performance improvement initiative that collects patient level data on characteristics, diagnostic testing, treatments, adherence to quality measures, and in-hospital outcomes in patients hospitalized with stroke, including ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage, as well as patients with TIA (limited to those presenting with symptoms at time of arrival). Details of the design and conduct of the GWTG-Stroke Program have been previously described.7,8 The purpose of this performance improvement registry is to develop and implement systems for collecting data on acute stroke and TIA care provided to patients, analyzing the collected data, and using the results of those analyses to guide quality improvement interventions at the hospital level through collaborative efforts with stroke-care teams, quality personnel, and administrators. GWTG uses a Web-based patient management tool (PMT, Outcome, Cambridge, Mass) to collect clinical data, provide decision support, and real-time online reporting features. After an initial pilot phase conducted in 8 states starting in 2001, the GWTG-Stroke Program was made available in April 2003 to any hospital in the United States.7,8 Data from the first 1 000 000 stroke and TIA patient cohort entered from hospitals that joined the program anytime between April 1, 2003, and August 24, 2009, were included in this analysis. Each participating hospital received either human research approval to enroll cases without individual patient consent under the common rule, or a waiver of authorization and exemption from subsequent review by their institutional review board. Outcome Sciences Inc serves as the data collection and coordination center for GWTG. The Duke Clinical Research Institute serves as the data analysis center and has an agreement to analyze the aggregate deidentified data for research purposes.
Case Identification and Data Abstraction
Trained hospital personnel were instructed to ascertain consecutive patients admitted with acute ischemic stroke by either prospective clinical identification, retrospective identification using International Classification of Diseases (ICD)-9 discharge codes, or a combination.7,8 ICD-9 codes used to identify ischemic stroke hospitalizations included 433.x, 434.x and 436; hemorrhagic stroke hospitalizations included 430.x, 431.x, and 432.x; and TIA cases were identified using 435.x. Hospitals could chose whether or not to record data from consecutive hemorrhagic stroke admissions and TIA with symptoms present on arrival, in addition to consecutive ischemic stroke admissions. Methods used for prospective identification varied but included regular surveillance of emergency department records (ie, presenting symptoms and chief complaints), ward census logs, and/or neurological consultations. The eligibility of each acute stroke or TIA admission was confirmed at chart review before abstraction.
Patient data were abstracted by trained hospital personnel using an Internet-based Patient Management Tool (PMT) (Outcome Sciences, Cambridge, Mass). These included demographics, medical history, initial head computerized tomography findings, in-hospital treatment and events, discharge treatment and counseling, mortality, and discharge destination. The data abstraction tool included predefined logic features and user alerts to identify potentially invalid format or values entry. Sites received individual data quality reports to promote data completeness and accuracy. Additional descriptions of the case ascertainment, data collection, and quality auditing methods have been previously published.7,8 Data on hospital-level characteristics (ie, bed size, academic or nonacademic status, annual volume of stroke discharges, and geographical region) and the number of US acute care hospitals were obtained from the American Hospital Association database.13
Among all stroke and TIA admissions from hospitals that participated in the program between April 1, 2003, and August 24, 2009, from 1419 hospitals, we excluded 9646 (1.0%) cases from 25 hospitals that provided incomplete medical history data, and 1021 (0.1%) cases were excluded because of missing information on sex or age. The final analysis sample consisted of 1 000 000 stroke or TIA admissions from 1392 hospitals.
Quality of Care Definitions
The GWTG-Stroke Program developed a set of process based measures to quantify the quality of care for stroke and TIA patients. In 2007, the AHA/ASA came to an agreement with The Joint Commission’s Primary Stroke Center Certification program and Center for Disease Control Coverdell Registry to jointly release a set of standardized stroke performance measures for use by all 3 programs. These measures have been endorsed by the National Quality Forum. The following 7 performance measures, selected as primary targets for stroke quality improvement efforts,8 were used to evaluate the quality of care in stroke and TIA admissions for this patient cohort (see Appendix for detailed specifications):
Acute Performance Measures
Intravenous recombinant tissue plasminogen activator (IV tPA) in patients who arrive <2 hours after symptom onset and treated within 3 hours of symptom onset (IV tPA <2 Hour) (ischemic stroke only).
Antithrombotic medication (antiplatelet or anticoagulant) prescribed within 48 hours of admission (Early Antithrombotics) (ischemic stroke and TIA).
Deep Venous Thrombosis (DVT) prophylaxis (warfarin, heparin, low-molecular-weight heparin, other anticoagulant, pneumatic compression devices) within 48 hours of admission in patients at risk for DVT (nonambulatory) (DVT Prophylaxis) (all strokes).
Discharge Performance Measures
Antithrombotic medication (antiplatelet or anticoagulant) prescribed at discharge (Antithrombotics) (ischemic stroke and TIA).
Anticoagulation prescribed at discharge in patients with documented atrial fibrillation (Anticoagulation for AF) (ischemic stroke and TIA).
Lipid-lowering medication prescribed at discharge if LDL ≥100 mg/dL, if patient treated with lipid-lowering agent before admission, or LDL not documented (LDL 100 or ND) (ischemic stroke and TIA).
Smoking cessation intervention (counseling or medication) at discharge for current or recent smokers (Smoking Cessation) (all patients).
The following additional measures, referred to as quality measures, have also been used to quantify the processes of care provided to patients enrolled in GWTG-Stroke (see Appendix for detailed specifications):
Door to CT time ≤25 minutes in patients presenting with stroke symptoms <3 hours’ duration (Door to CT ≤25 Minutes).
Dysphagia screening before any oral intake (Dysphagia Screening).
Stroke education provided to patient and/or caregiver, all 5 components: modifiable risk factors, stroke warning sign and symptoms, how to activate Emergency Medical Services, need for follow-up, medications prescribed (Stroke Education).
Patient was assessed for and/or received stroke rehabilitation services (Rehabilitation).
Performance and quality measures are applied only to eligible patients in the absence of documented contraindications or any other rationale as to why therapy was not provided. Data collection for 2 quality measures, stroke education and rehabilitation, did not commence until 2008. Two different measures were used to summarize the overall conformity with performance measures.8 An all-or-none measure of care was used, which is defined as the proportion of patients who received all of the performance measure interventions for which they were eligible. A composite measure of care, defined as the total number of performance measure interventions performed among eligible patients divided by the total number of possible performance measure interventions among eligible patients, was also calculated. For subarachnoid hemorrhage, intracranial hemorrhage, and stroke not classified, the summary measures are drawn from only the few performance measures applicable to these stroke types. In-hospital outcome measures assessed in this study included in-hospital mortality, discharge to home (discharge status home versus other), and hospital length of stay (LOS).
Contingency tables were generated to explore the relationship between cerebrovascular event type and patient demographic, clinical variables, treatments, quality measures, in-hospital outcomes, and hospital-level characteristics. For these analyses, data were analyzed overall and by each cerebrovascular event type: ischemic stroke, subarachnoid hemorrhage, intracerebral hemorrhage, stroke not classified, and TIA. Pearson χ2 tests were used to evaluate the statistical associations for all categorical row variables and Kruskal-Wallis tests were used for all continuous/ordinal variables. Because of the large size of the data set, statistical significance was defined as P≤0.01. Pairwise comparisons were also performed with the Bonferroni correction to limit problems with multiplicity. The relationship between cerebrovascular event type and 3 binary outcome measures in-hospital mortality, discharge status (home versus other), and length of stay (LOS) (>4 days versus ≤4 days, this cut-point represented the median LOS) were further examined using multivariable logistic regression models. To account for within-hospital clustering, generalized estimating equations (GEE) were used to generate both unadjusted and adjusted models. Given the large data set, traditional model building approaches that identify independent predictors based on statistical significance were not used. Instead, the final models were adjusted for the following prespecified potential confounders identified in prior GWTG-Stroke studies: age; sex; race; on or off hour arrival time; emergency medical service transport; and medical history of atrial fibrillation, previous stroke/transient ischemic attack, coronary heart disease or prior myocardial infarction, carotid stenosis, diabetes, peripheral vascular disease, hypertension, dyslipidemia, and current smoking; and hospital size, region, and type. The variables most predictive of in-hospital mortality in GEE models for each cerebrovascular event type were also compared.
Finally, we also explored temporal trends in quality of care and clinical outcomes. Compliance with individual performance measures, summary measures, in-hospital mortality, discharge home, and LOS >4 days was compared. Probability values were based on χ2 rank based group means score statistics for all categorical row variables (equivalent to Wilcoxon test for 2 levels). For the composite measure, the probability value was based on χ2 1 degree of freedom rank correlation statistics. GEE multivariable logistic regression models were developed to quantify how the all-or-none care measure, in-hospital mortality, discharge home, and LOS changed on a continuous basis by quarter from 2003 to 2009 and reported as cumulative change over 6 years for the entire cohort and for each cerebrovascular event type adjusting for patient variables, hospital variables, and cerebrovascular event type. Because the makeup of participating hospitals may have changed over time in GWTG-Stroke, we also performed a separate set of analyses for temporal trends among core hospitals which were participating by 2004 and contributed cases in all subsequent quarters of the study for the all-or-none measure, in-hospital mortality, discharge home, and LOS >4 days. There were 301 core hospitals enrolling 468 087 patients over the course of the study.
All statistical analyses were performed using SAS Version 9.1 software (SAS Institute, Cary, NC). The authors had full access to the data and take responsibility for its integrity. All authors have read and agree to the manuscript as written.
Enrollment in GWTG-Stroke increased progressively from April 2003 (Figure 1). For the 1 000 000 acute stroke (n=772 212) and TIA (n=227 788) admissions entered into the program, the mean age was 70.1±14.9 years and more than half (53.5%) were women. There were 601 599 (60.2%) ischemic strokes, 108 671 (10.9%) intracerebral hemorrhages, 34 945 (3.5%) subarachnoid hemorrhages, 26 977 (2.7%) strokes not classified, and 227 788 (22.8%) TIA patients. Table 1 compares the demographic and clinical characteristics by cerebrovascular event group. Ischemic stroke and TIA patients were older, more likely to be men, less likely to be smokers, and more likely to have medical comorbidities than intracerebral hemorrhage and subarachnoid hemorrhage patients. Intracerebral hemorrhage patients had a relatively high prevalence of vascular risk factors, but not as high as for ischemic stroke or TIA patients. Patients with stroke not classified were most similar to ischemic stroke patients. Subarachnoid hemorrhage patients were more likely than ischemic stroke or TIA patients to be younger, female, nonwhite, and to be cared for in larger academic hospitals (Table 1).
Of the 1392 hospitals participating in the GWTG-Stroke program, 39.5% were nonacademic institutions (Table 1). Median bed size was 369; 19 institutions are under 25 beds, 141 hospitals have between 25 to 99 beds, 531 hospitals have between 100 to 299 beds, 343 hospitals have between 300 to 499 beds, and 194 hospitals have 500 beds or more. Hospitals in every state participate in the GWTG-Stroke Program (Figure 2). Divided by regions, the South has the largest number of participating hospitals (n=500), followed by the Northeast (n=346), the Midwest (n=325), and the West (n=252). GWTG-Stroke participating hospitals account for an estimated 32.3% of US acute care hospitals. In 2008, there were 156 000 ischemic stroke patients entered into GWTG-Stroke of 663 000 expected in the United States (25%) and 47 937 hemorrhagic stroke patients entered of 117 000 expected in the United States (41%).1
Performance measures conformity is shown in Table 2. Conformity to measures that were applicable to all cerebrovascular event patient types, smoking cessation and stroke education was higher in patients with ischemic stroke and TIA. The largest differences in performance measures by cerebrovascular event type were seen in the proportion of patients receiving DVT prophylaxis, ranging from 80.8% in patients with stroke not classified to 91.5% in subarachnoid hemorrhage patients (see appendix for pairwise comparisons). The composite measure ranged from 81.1% in stroke-not-classified patients to 89.5% in subarachnoid hemorrhage (Table 2).
We observed important differences in unadjusted stroke-related in-hospital outcomes (Table 3). Subarachnoid hemorrhage and intracerebral hemorrhage patients had substantially higher in-hospital mortality rates, were less likely to be discharged home, and were more likely to be discharged to a skilled nursing facility or hospice compared with ischemic stroke patients. As expected, in-hospital mortality was very low in patients hospitalized with TIA (0.3%). Length of stay was significantly longer in subarachnoid and intracerebral hemorrhage patients and, as expected, shortest in TIA patients (see Appendix for pairwise comparisons). Adjustment for potential confounding variables and clustering of data within hospitals did little to attenuate the cerebrovascular event type related differences for clinical outcomes (Table 4). The adjusted odds ratio (OR) for in-hospital mortality for intracerebral hemorrhage compared with ischemic stroke was 5.8; for subarachnoid hemorrhage it was 5.4. In contrast the adjusted OR for in-hospital mortality was 0.06 for TIA compared with ischemic stroke. After adjustment the odds of being hospitalized longer than 4 days remained significantly elevated for subarachnoid hemorrhage and intracerebral hemorrhage compared to ischemic stroke.
The factors most predictive of in-hospital mortality for each cerebrovascular event type are shown in Table 5. Age and arrival by Emergency Medical Services were among the strongest predictors of mortality for each cerebrovascular event type. A history of atrial fibrillation was the strongest predictor of mortality in patients with ischemic stroke but was not independently predictive of mortality among patients with subarachnoid hemorrhage. A history of coronary artery disease or myocardial infarction was associated with increased mortality risk for each cerebrovascular event type. A history of hypertension was associated with higher mortality in patients with subarachnoid hemorrhage but lower risk among patients with other cerebrovascular event types.
In each successive year, there were clinically meaningful and statistically significant improvements in all 7 individual performance measures (Figure 3 and Appendix). The absolute improvement from 2003 to 2009 ranged from +4.3% for discharge antithrombotics to +51.0% for smoking cessation (P<0.0001 for all comparisons) (Figure 3). IV tPA use in eligible patients increased from 29.7% to 71.6% (+41.9%, P<0.0001). For measures with high compliance rates in 2003 (>90%), there were smaller absolute gains. In addition, there was substantial and significant improvement in the all-or-none care measure from 2003 to 2009, 44.0% to 84.3% (+40.3%, P<0.0001) overall (Figure 3) and for each cerebrovascular event type (Appendix). There was also an increase in composite care from 72.3% to 93.1% (+20.8%) (Appendix). Multivariate GEE analysis showed that over the study period there was a significant increase in the odds of receiving guideline recommended all-or-none care, independent of patient and hospital characteristics, 2003 to 2009 cumulative adjusted odds ratio 9.4 (95% confidence interval, 8.3 to 10.6, P<0.0001) (Table 6).
There were temporal trends for improvement in clinical outcomes from 2003 to 2009. The portion of patients discharged home in 2003 was 53.8% compared with 57.1% in 2009 (P<0.0001) and LOS >4 days was seen in 40.1% in 2003 compared with 35.6% in 2009. Figure 4 shows temporal trends for in-hospital mortality overall and by each event type. The cumulative temporal trends from 2003 to 2009 for unadjusted and adjusted risk for clinical outcomes overall and analyzed for each cerebrovascular event type are shown in Table 6. After adjusting for potential confounding variables and factoring in the correlation of data within each participating hospital with multivariate GEE analyses, the portion of patients with hospital LOS >4 days declined significantly (adjusted OR, 0.72; 95% confidence interval, 0.69 to 0.77, P<0.0001) from 2003 to 2009 (Table 6). In-hospital mortality also declined significantly over time (unadjusted OR, 0.87; 95% confidence interval, 0.80 to 92, P<0.001, 2003 to 2009) but after risk adjustment was only significant for ischemic stroke and TIA (Table 6). Adjusted and unadjusted ORs for temporal trend per 1-year interval are shown in the Appendix.
When the temporal tend analyses were confined to core hospitals (n=301) participating throughout the study there were significant improvements in each of the individual performance measures and the all-or-none summary measure, similar to what was observed among the entire group participating hospitals during the study period (appendix). Multivariate GEE analysis showed that over the study period in core hospitals there was a significant increase in the odds of receiving guideline recommended all-or-none care, independent of patient and hospital characteristics, 2003 to 2009 cumulative adjusted odds ratio 9.7, 95% confidence interval 8.0 to 11.8, P<0.0001 There were also improvements in clinical outcomes for patients among core hospital that were similar to the entire group of participating hospitals (Appendix).
GWTG-Stroke is the largest registry and performance improvement programs for hospitalized stroke and TIA patients, with data from 1 000 000 admissions including more than 600 000 ischemic stroke, 100 000 intracerebral hemorrhage, 30 000 subarachnoid hemorrhage, and 225 000 TIA admissions. Stroke admissions were recorded from a large variety of hospitals from all regions of the United States, and included a mix of academic and nonacademic, and small- and large-sized hospitals.8 The prevalence and characteristics of stroke and TIA patients in this study are similar to those previously reported in epidemiological studies.1,4,14,15 Overall, 88% of the opportunities to provide guideline recommended care addressed by the performance measures were fulfilled. Adherence to performance measures varied by the type of cerebrovascular event. In-hospital mortality rates were substantially higher among intracerebral hemorrhage patients and subarachnoid hemorrhage and substantially lower among TIA patients, compared with ischemic stroke patients, differences that persisted after risk adjustment. Substantial improvements in quality of stroke and TIA care were observed from 2003 to 2009. Improvements in hospital length of stay and in-hospital mortality were also observed, but after risk adjustment only patients with ischemic stroke and TIA had significant reductions of in-hospital mortality over time.
The patients enrolled in GWTG-Stroke appear comparable to those included in national and community data sets. Prior community based studies have suggested that of all strokes, 87% are ischemic, 10% are intracerebral hemorrhage, and 3% are subarachnoid hemorrhage strokes.15 Similar distribution of stroke type were reported in a study of Medicare beneficiaries age 65 years and older hospitalized with stroke.16 In an analysis of National Hospital Discharge Survey (NHDS) data, of 726 000 stroke hospitalizations in the United States in 2004, there were 64% classified as ischemic, 16% as hemorrhagic, 16% as ill-defined, and 4% as late effects.14 Other characteristics of this nationally representative population were also similar to our GWTG-Stroke population—for example, the mean age was 71 years, median LOS of 4 days, and in-hospital mortality rates of 5.5%.14 The comparability of GWTG-Stroke cases with other large stroke study populations add to the growing evidence that the selection of participating hospitals in clinical registries does not necessarily result in substantial bias and that well-designed clinical registries can enroll patients and produce findings similar to those from entire community cohorts or national data sets.17
This is the largest report to date of acute stroke and TIA care among hospitalized patients. There were substantial absolute percentage improvements in a wide variety of acute stroke care and secondary prevention performance measures over 6 consecutive years, despite the diverse nature of the participating hospitals. The study clearly shows the feasibility of collecting detailed clinical data on demographics, treatments, quality of care, and in-hospital outcomes in a very large number of hospitalized stroke and TIA patients and has broad implications for the potential to measure, track, and improve stroke and TIA care across the country and elsewhere.
Age, sex, risk factors, comorbidities, and patient preference are often used to explain gaps, variations, and disparities in stroke care.4–6 However, there was progressive improvement and for certain measures striking improvements in care over time, suggesting that a substantial proportion of patients not receiving guideline recommended care in earlier years were due to less reliable systems being in place to facilitate high quality care. In this study, adjustment for differences in patient and hospital characteristics had little impact on temporal improvements in the summary all-or-none care measure. A prior analysis of GWTG-Stroke data demonstrated improvements in care related to time of exposure to the program, independent of changes in patient characteristics, hospital characteristics, or secular trend.8 This present study in which exposure to the GWTG-Stroke Program exits alongside other quality improvement efforts such as The Joint Commission Primary Stroke Center certification, as well as secular trends, demonstrates dramatic improvement in care from 2003 to 2009, independent of differences in patient or hospital characteristics.
Very few studies have examined differences in the care of acute stroke patients by type of cerebrovascular event. A prior GWTG-Stroke study reported a comparison of patients with ischemic stroke/TIA compared with subarachnoid hemorrhage and intracerebral hemorrhage patients.18 This study found differences in the use of specific diagnostic and treatment procedures by stroke type and have suggested that there may be cerebrovascular event related differences in the quality of in-hospital care for those guideline recommended measures that apply to all stroke types.18 The reasons why differences in the quality of care by cerebrovascular event type remain after adjustment for baseline differences needs further study.1,18–20 One possible explanation is that these differences are due to residual confounding by other unmeasured factors such as stroke severity and prestroke functional status. There may be uncertainty about risks versus benefits for stroke-related care, especially since subarachnoid hemorrhage and intracerebral hemorrhage patients have often been underrepresented in controlled trials.18,21 Less frequent use of evidence-based care may also be the choice of the patient or family, or may be a reflection of physician or hospital-related factors. Only limited information on these factors is obtained in the GWTG-Stroke program.
Consistent with prior reports,1,18–20 subarachnoid hemorrhage and intracerebral hemorrhage patients in our study had a higher in-hospital mortality rates than ischemic stroke patients, and this difference was not reduced after risk adjustment for sex, comorbidities, and other baseline differences. Reports assessing acute stroke type and stroke case fatality have also suggested a substantial difference in outcomes based on neurological event type. Certain prognostic variables such as age, arrival by Emergency Medical Services, and history of coronary artery disease were associated with increased mortality risk for each cerebrovascular event type, but, for other variables there were different relationships, depending on type of event. Mortality rates reported here are lower than other estimates of 30-day mortality,1,19,20 at least partly because out-of-hospital deaths and emergency room deaths were, by design, not included in GWTG-Stroke. Some of these prior studies have been limited either by their relatively small number of participating hospitals or their duration of participation.
There were significant temporal improvements in clinical outcomes, including LOS and in-hospital mortality, observed from 2003 to 2009. GWTG-Stroke provides hospitals with real-time benchmarked quality of care and outcome reports, performance improvement tools, clinical decision support, best practice examples, and collaborative educational opportunities.7,8 These process improvements may have translated into the modestly improved outcomes observed. However, it is important to note that most stroke process measures are aimed at reducing long-term disability and preventing recurrent cardiovascular events but are not likely to be reflected by in-hospital mortality. Whether the improvements in clinical outcomes over time in the GWTG-Stroke cohort are the result of improved stroke care, national secular trends, or other factors requires further study.
A major strength of this study is prospective data collection, national scope (≈1400 centers), very large cohort of acute stroke and TIA patients (1 million), duration (>6 years), and collection of detailed data on a range of specific processes of care. Importantly, only patients eligible for each measure and without any documented contraindications for the specific processes of care were included. Furthermore, while examining the relationship between cerebrovascular event type and clinical outcomes, we reduced confounding by adjusting for a wide range of patient and hospital characteristics. GWTG-Stroke is a dynamic program and continues to undergo enhancements with additional process and outcome measures based on new clinical science and guidelines, dissemination of stroke/TIA best practices and tools, addition of personalized patient educational materials, interfaces with multiple electronic heath records systems, and links to the ambulatory care setting.
GWTG-Stroke and this study have several limitations. The GWTG program is voluntary and the hospitals that participate are more likely to be larger teaching hospitals with a strong interest in stroke and quality improvement. However, the population in GWTG-Stroke is similar in makeup to other large stroke registries.6,11,12,19 It was not possible to account for stroke severity in these analyses because the NIHSS is inconsistently documented in the database, and so NIHSS inclusion in the multivariable models may have introduced significant selection bias. Data on other potentially important comorbid conditions such as heart failure and chronic kidney disease were not collected. Residual measured and unmeasured confounding may influence the results of the multivariable analyses. Because of the large sample size some results may be statistically significant but not clinically meaningful. Hospitals are instructed to include all consecutive ischemic stroke admissions or to take a systematic sample after selecting a random starting point. However, since these processes are not audited, the potential exists for selection bias.4 Hospitals could chose whether or not to enter consecutive hemorrhagic stroke patients and only TIA patients with symptoms at time of presentation and that were hospitalized were included. As a result, there is greater potential for selection bias among patients with hemorrhagic stroke and those hospitalized with TIA. Only in-hospital quality of care and mortality were assessed, so temporal trends and differences by cerebrovascular event type in postdischarge care and outcomes could not be determined. We defined quality of care using only 7 predefined performance measures and 4 quality measures that address acute and discharge care. These measures do not apply uniformly to all cerebrovascular event types and other measures which may be more useful to access care quality for hemorrhagic stroke were not assessed.
Using data collected as part of the GWTG-Stroke, the present study has characterized the demographics, performance measures, and in-hospital clinical outcomes in a very broad cohort of 1 million acute stroke and TIA hospitalizations from every state in the country. Performance measures showed small to moderate differences by cerebrovascular event type. Among hospitals participating in this large quality improvement effort, there were substantial improvements over time in performance measures, overall and for each cerebrovascular event type. Temporal improvements in length of stay and risk-adjusted in-hospital mortality for ischemic stroke and TIA were also observed. The present study demonstrates the ongoing value of GWTG-Stroke as an integrated stroke and TIA national registry providing national surveillance, supporting vigorous efforts to improve evidence-based stroke/TIA care, and fostering innovative research.
Sources of Funding
GWTG-Stroke is a program of the American Heart Association/American Stroke Association and is supported in part by an unrestricted educational grant from Merck/Schering-Plough Pharmaceutical, which did not participate in the design, analysis, manuscript preparation, review, or approval of this manuscript.
Dr Fonarow receives research support from the National Institutes of Health (significant) and served as a consultant to Pfizer, Merck, Schering Plough, Bristol Myers Squibb, and Sanofi-Aventis (all modest); received speaker honoraria from Pfizer, Merck, Schering Plough, Bristol Myers Squibb, and Sanofi-Aventis (all significant), and is an employee of the University of California, which holds a patent on retriever devices for stroke (significant). Dr Reeves receives salary support from the Michigan Stroke Registry. Dr Smith receives research support from the NIH (NINDS R01 NS062028) and the Canadian Stroke Network, and salary support from the Heart and Stroke Foundation of Canada and the Canadian Institute for Health Research. Dr Zhao is a member of the Duke Clinical Research Institute, which serves as the AHA GWTG data coordinating center. Dr Olson is a member of the Duke Clinical Research Institute which serves as the AHA GWTG data coordinating center. Dr Hernandez reports receiving research grants from Johnson & Johnson (Scios, Inc), Medtronic, Merck, and receiving honoraria from AstraZeneca, Geron, Medtronic, Novartis, and Sanofi-Aventis. Dr Hernandez has made available online detailed listings of financial disclosures (http://www.dcri.duke.edu/research/coi.jsp). Dr Peterson reports receiving research grants from BMS/Schering Plough and serves as the principal investigator of the AHA’s GWTG Analytical Center. Dr Saver serves as a member of the Get With the Guidelines Science Subcommittee, as a scientific consultant regarding trial design and conduct to CoAxia, Concentric Medical, Talecris, and Cygnis (all modest), received lecture honoraria from Ferrer and Boehringer Ingelheim (modest), received devices for use in an NIH multicenter clinical trial from Concentric Medical (modest), was an unpaid investigator in a multicenter prevention trial sponsored by Boehringer Ingelheim, has declined consulting/honoraria monies from Genentech since 2002, and is an employee of the University of California, which holds a patent on retriever devices for stroke. Dr Schwamm serves as a consultant to the Research Triangle Institute, CryoCath, and to the Massachusetts Department of Public Health.
The online-only Data Supplement is available at http://circoutcomes.ahajournals.org/cgi/content/full/CIRCOUTCOMES.109.921858/DC1.
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