S Claiborne Johnston

University of Texas at Austin, Austin, Texas, United States

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Publications (374)3080.34 Total impact

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    ABSTRACT: Background and purposeThe Totaled Health Risks in Vascular Events (THRIVE) score is a previously validated ischemic stroke outcome prediction tool. Although simplified scoring systems like the THRIVE score facilitate ease-of-use, when computers or devices are available at the point of care, a more accurate and patient-specific estimation of outcome probability should be possible by computing the logistic equation with patient-specific continuous variables.Methods We used data from 12 207 subjects from the Virtual International Stroke Trials Archive and the Safe Implementation of Thrombolysis in Stroke – Monitoring Study to develop and validate the performance of a model-derived estimation of outcome probability, the THRIVE-c calculation. Models were built with logistic regression using the underlying predictors from the THRIVE score: age, National Institutes of Health Stroke Scale score, and the Chronic Disease Scale (presence of hypertension, diabetes mellitus, or atrial fibrillation). Receiver operator characteristics analysis was used to assess model performance and compare the THRIVE-c model to the traditional THRIVE score, using a two-tailed Chi-squared test.ResultsThe THRIVE-c model performed similarly in the randomly chosen development cohort (n = 6194, area under the curve = 0·786, 95% confidence interval 0·774–0·798) and validation cohort (n = 6013, area under the curve = 0·784, 95% confidence interval 0·772–0·796) (P = 0·79). Similar performance was also seen in two separate external validation cohorts. The THRIVE-c model (area under the curve = 0·785, 95% confidence interval 0·777–0·793) had superior performance when compared with the traditional THRIVE score (area under the curve = 0·746, 95% confidence interval 0·737–0·755) (P < 0·001).Conclusion By computing the logistic equation with patient-specific continuous variables in the THRIVE-c calculation, outcomes at the individual patient level are more accurately estimated. Given the widespread availability of computers and devices at the point of care, such calculations can be easily performed with a simple user interface.
    International Journal of Stroke 07/2015; DOI:10.1111/ijs.12529 · 4.03 Impact Factor
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    ABSTRACT: To investigate the prevalence, knowledge, and treatment of TIA in a Chinese adult population. We conducted a complex, multistage, probability sampling-designed, cross-sectional, nationwide survey of 98,658 Chinese adults in 2010. Possible TIA cases were first identified by symptoms recall or self-reported history of TIA through face-to-face interviews, and the final diagnosis was then made by expert neurologists through phone interviews or record review. The age-standardized prevalence of TIA was 2.27%. Clinically, only 16.0% of the participants were diagnosed before the study. The prevalence of TIA was higher in women and in patients who were older, had less education, were current smokers, lived in rural or undeveloped areas, and had a history of stroke, hypertension, myocardial infarction, dyslipidemia, or diabetes. Based on the survey responses, approximately 3.08% of Chinese adults had knowledge of TIA. Among patients with TIA, only 5.02% received treatment and 4.07% received guideline-recommended therapy. TIA is prevalent and an estimated 23.9 million people in China may have experienced a TIA. Public knowledge on TIA is very limited. TIA appears to be largely undiagnosed and untreated in China. There is an urgent need to develop strategies to improve the identification and appropriate management of TIA. © 2015 American Academy of Neurology.
    Neurology 05/2015; 84(23). DOI:10.1212/WNL.0000000000001665 · 8.30 Impact Factor
  • PLoS ONE 03/2015; 10(3):e0121273. DOI:10.1371/journal.pone.0121273 · 3.53 Impact Factor
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    ABSTRACT: Objectives The objective of this study was to examine prehospital provider recognition of stroke by race and sex.Methods Diagnoses at emergency department (ED) and hospital discharge from a statewide database in California were linked to prehospital diagnoses from an electronic database from two counties in Northern California from January 2005 to December 2007 using probabilistic linkage. All patients 18 years and older, transported by ambulances (n = 309,866) within the two counties, and patients with hospital-based discharge diagnoses of stroke (n = 10,719) were included in the study. Logistic regression was used to analyze the independent association of race and sex with the correct prehospital diagnosis of stroke.ResultsThere were 10,719 patients discharged with primary diagnoses of stroke. Of those, 3,787 (35%) were transported by emergency medical services providers. Overall, 32% of patients ultimately diagnosed with stroke were identified in the prehospital setting. Correct prehospital recognition of stroke was lower among Hispanic patients (odds ratio [OR] = 0.77, 95% confidence interval [CI] 0.61 to 0.96), Asians (OR = 0.66, 95% CI 0.55 to 0.80), and others (OR = 0.71, 95% CI = 0.53 to 0.94), when compared with non-Hispanic whites, and in women compared with men (OR = 0.82, 95% CI = 0.71 to 0.94). Specificity for recognizing stroke was lower in females than males (OR = 0.84, 95% CI = 0.78 to 0.90).Conclusions Significant disparities exist in prehospital stroke recognition.
    Academic Emergency Medicine 02/2015; DOI:10.1111/acem.12595 · 2.20 Impact Factor
  • C G McDougall, S C Johnston, A Gholkar, A S Turk
    American Journal of Neuroradiology 11/2014; 36(1). DOI:10.3174/ajnr.A4205 · 3.68 Impact Factor
  • Jay Chol Choi, S Claiborne Johnston, Anthony S Kim
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    ABSTRACT: Despite the absence of definitive data from randomized clinical trials on the comparative effectiveness of carotid artery stenting (CAS) versus carotid endarterectomy (CEA) for asymptomatic carotid stenosis, the use of CAS has been expanding and seems to be displacing the use of CEA in some parts of the United States. We used comprehensive hospital discharge data from January 2010 to December 2012 to identify patients who had CEA or CAS for asymptomatic carotid stenosis at all academic medical centers that participate in the University HealthSystem Consortium. In-hospital death and postoperative stroke after CAS and after CEA were compared using multivariable logistic regression, propensity score matching, and a grouped-treatment approach using multilevel mixed-effects models to adjust for baseline characteristics of patients selected for these procedures. We identified 17 716 patients with asymptomatic carotid stenosis treated with CEA and 3962 treated with CAS at 186 University HealthSystem Consortium hospitals. Postoperative stroke or in-hospital death was more frequent after CAS (4.0% versus 1.5%; P<0.001), and patients with CAS were more likely to have these adverse outcomes even after adjusting for baseline characteristics using multivariable analysis (odds ratio [OR], 2.5; 95% confidence interval [CI], 2.1-3.1; P<0.001) and propensity score matching (OR, 2.5; 95% CI, 1.9-3.4; P<0.001). In a multilevel mixed-effects model, hospitals that performed a higher proportion of all carotid revascularization cases using CAS had significantly higher rates of adverse outcomes (OR, 3.7; 95% CI, 1.8-7.6; P<0.001) after adjusting for patient-level variables. For asymptomatic carotid stenosis, CAS is associated with a substantially higher risk of postoperative stroke or in-hospital death than CEA even after adjustment for baseline differences in hospital and patient characteristics. © 2014 American Heart Association, Inc.
    Stroke 11/2014; 46(1). DOI:10.1161/STROKEAHA.114.006209 · 6.02 Impact Factor
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    ABSTRACT: To determine what the trends in stroke mortality have been over 2 decades in young adults.
    Neurology 10/2014; 83(23). DOI:10.1212/WNL.0000000000001042 · 8.30 Impact Factor
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    ABSTRACT: Statin use during hospitalization is associated with improved survival and a better discharge disposition among patients with ischemic stroke. It is unclear whether inpatient statin use has a similar effect among patients with intracerebral hemorrhage (ICH).
    JAMA Neurology 09/2014; 71(11). DOI:10.1001/jamaneurol.2014.2124 · 7.01 Impact Factor
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    ABSTRACT: AimsTo examine the health-related quality of life (HRQOL) in patients with transient ischemic attack (TIA) or minor stroke and assess the impact of recurrent stroke on HRQOL.Methods Health-related quality of life data on patients participated in the Clopidogrel in High-risk patients with Acute Nondisabling Cerebrovascular Events (CHANCE) trial were analyzed. The available 90-day EuroQoL data (EQ-5D) were used to calculate EQ-5D index score. Poor HRQOL was defined as an EQ-5D index score ≤0.5. The characteristics of HRQOL and factors predicting poor HRQOL in these patients were then explored.ResultsAmong the total 5170 patients enrolled, 90-day HRQOL data were obtained from 5104 patients for analysis. The mean EQ-5D index score at day 90 was 0.88 ± 0.21 for all patients, but only 0.42 ± 0.35 for those with recurrent strokes. Poor 90-day HRQOL was found in 294 (5.8%) patients. Patients with poor HRQOL had more strokes during follow-up than patients with good HRQOL (94.9 vs. 4.7%, P < 0.001). Age, history of hypertension and diabetes, and NIHSS at baseline were independent risk factors for predicting poor HRQOL. Stroke recurrence, NIHSS at baseline, age, and minor stroke on admission became independent risk factors once stroke recurrence was added into the model.Conclusions Stroke recurrence was associated with poor HRQOL in patients with TIA or minor strokes. Interventions focusing on controlling risk factors and prevention of worsening of neurological function may prevent poor HRQOL in these patients.
    CNS Neuroscience & Therapeutics 09/2014; DOI:10.1111/cns.12329 · 3.78 Impact Factor
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    ABSTRACT: Background Medical devices are often introduced prior to randomized-trial evidence of efficacy and this slows completion of trials. Alternative regulatory approaches include restricting device use outside of trials prior to trial evidence of efficacy (like the drug approval process) or restricting out-of-trial use but permitting coverage within trials such as Medicare's Coverage with Study Participation (CSP).Methods We compared the financial impact to manufacturers and insurers of three regulatory alternatives: (1) limited regulation (current approach), (2) CSP, and (3) restrictive regulation (like the current drug approval process). Using data for patent foramen ovale closure devices, we modeled key parameters including recruitment time, probability of device efficacy, market adoption, and device cost/price to calculate profits to manufacturers, costs to insurers, and overall societal impact on health.ResultsFor manufacturers, profits were greatest under CSP—driven by faster market adoption of effective devices—followed by restrictive regulation. Societal health benefit in total quality-adjusted life years was greatest under CSP. Insurers’ expenditures for ineffective devices were greatest with limited regulation. Findings were robust over a reasonable range of probabilities of trial success.Conclusions Regulation restricting out-of-trial device use and extending limited insurance coverage to clinical trial participants may balance manufacturer and societal interests. Clin Trans Sci 2014; Volume #: 1–8
    Clinical and Translational Science 08/2014; 7(5). DOI:10.1111/cts.12199 · 2.11 Impact Factor
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    ABSTRACT: Objective. A better understanding of the manuscript peer-review process could improve the likelihood that research of the highest quality is funded and published. To this end, we aimed to assess consistency across reviewers’ recommendations; agreement between reviewers’ recommendations and editors’ final decisions; and reviewer- and editor-level factors influencing editorial decisions in STROKE Journal.Methods. We analyzed all initial original contributions submitted to STROKE from January 2004 through December 2011. All submissions were linked to the final editorial decision (accept vs. reject). We assessed the level of agreement between reviewers (intraclass correlation coefficient). We compared the initial editorial decision (accept, minor revision, major revision and reject) across reviewers’ recommendations. We performed a logistic regression analysis to identify reviewer- and editor-related factors related to acceptance as the final decision.Results. Of 12,902 original submissions to STROKE during the 8-year study period, the level of agreement between reviewers was between fair and moderate (intraclass correlation coefficient 0.55, 95%CI: 0.09-0.75). Likelihood of acceptance was less than 5% if at least one reviewer recommended a rejection. In the multivariable analysis, higher reviewer-assigned priority scores were related to greater odds of acceptance (OR 26.3, 95%CI: 23.2-29.8); while higher numbers of reviewers (OR 0.54 per additional reviewer, 95%CI: 0.50-0.59) and suggestions for reviewers by authors vs. no suggestions (OR 0.83, 95%CI: 0.73-0.94) had lesser odds of acceptance.Interpretation. This analysis of the peer-review process of STROKE identified several factors that might be targeted to improve the consistency and fairness of the overall process. ANN NEUROL 2014. © 2014 American Neurological Association
    Annals of Neurology 08/2014; 76(2). DOI:10.1002/ana.24218 · 11.91 Impact Factor
  • Jacob S Elkins, S Claiborne Johnston, Mitchell S V Elkind
    Stroke 07/2014; 45(9). DOI:10.1161/STROKEAHA.114.006592 · 6.02 Impact Factor
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    ABSTRACT: Background Clinical trials frequently spend considerable effort to collect data on patients who were assessed for eligibility but not enrolled. The Consolidated Standards of Reporting Trials (CONSORT) guidelines' recommended flow diagram for randomized clinical trials reinforces the belief that the collection of screening data is a necessary and worthwhile endeavor. The rationale for collecting screening data includes scientific, trial management, and ethno-socio-cultural reasons. Purpose We posit that the cost of collecting screening data is not justified, in part due to inability to centrally monitor and verify the screening data in the same manner as other clinical trial data. Methods To illustrate the effort and site-to-site variability, we analyzed the screening data from a multicenter, randomized clinical trial of patients with transient ischemic attack or minor ischemic stroke (Platelet-Oriented Inhibition in New Transient Ischemic Attack and Minor Ischemic Stroke (POINT)). Results Data were collected on over 27,000 patients screened across 172 enrolling sites, 95% of whom were not enrolled. Although the rate of return of screen failure logs was high overall (95%), there were a considerable number of logs that were returned with 'no data to report' (23%), often due to administrative reasons rather than no patients screened. Conclusion In spite of attempts to standardize the collection of screening data, due to differences in site processes, multicenter clinical trials face challenges in collecting those data completely and uniformly. The efforts required to centrally collect high-quality data on an extensive number of screened patients may outweigh the scientific value of the data. Moreover, the lack of a standardized definition of 'screened' and the challenges of collecting meaningful characteristics for patients who have not signed consent limits the ability to compare across studies and to assess generalizability and selection bias as intended.
    Clinical Trials 06/2014; DOI:10.1177/1740774514538706 · 1.94 Impact Factor
  • Stroke 06/2014; 45(6):1862-8. DOI:10.1161/STROKEAHA.114.005413 · 6.02 Impact Factor
  • Gustavo Saposnik, S Claiborne Johnston
    Stroke 05/2014; 45(7). DOI:10.1161/STROKEAHA.114.005462 · 6.02 Impact Factor
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    ABSTRACT: IMPORTANCE The Stroke Prognostication using Age and the NIH Stroke Scale index, created by combining age in years plus a National Institutes of Health (NIH) Stroke Scale score of 100 or higher (and hereafter referred to as the SPAN-100 index), is a simple risk score for estimating clinical outcomes for patients with acute ischemic stroke (AIS). The association between this index and response to intravenous thrombolysis for AIS has not been properly evaluated. OBJECTIVE To assess the relationship between SPAN-100 index status and outcome following treatment with intravenous thrombolysis for AIS. DESIGN, SETTING, AND PARTICIPANTS Using the Virtual International Stroke Trials Archive (VISTA) database, an international repository of clinical trials data, we assessed the SPAN-100 index among 7093 patients with AIS who participated in 4 clinical trials from 2000 to 2006. The SPAN-100 index is considered positive if the sum of the age and the NIH Stroke Scale (a 15-item neurological examination scale with scores ranging from 0 to 42, with higher scores indicating more severe strokes) score is greater than or equal to 100. Multivariable logistic regression analyses were used to determine the independent association between SPAN-100 index status and 90-day outcomes. MAIN OUTCOMES AND MEASURES The primary outcome was a composite of severe disability or death measured 90 days after stroke, and the secondary outcomes were death alone and a composite of no disability/modest disability. RESULTS Of 7093 patients, 743 (10.5%) were SPAN-100 positive, and 2731 (38.5%) received intravenous thrombolysis. Compared with SPAN-100-negative patients, SPAN-100-positive patients were more likely to experience a catastrophic outcome (adjusted odds ratio [AOR], 9.03 [95% CI, 6.68-12.21]) or death alone (AOR, 5.03 [95% CI, 4.06-6.23]) and less likely to experience a favorable outcome (AOR, 0.08 [95% CI, 0.06-0.13]). However, there was an interaction between SPAN-100 index status and thrombolysis treatment (P < .001) revealing a reduction in the likelihood of severe disability/death with thrombolytic treatment for SPAN-100-positive (AOR, 0.46 [95% CI, 0.29-0.71]) but not SPAN-100-negative patients (AOR, 0.96 [95% CI, 0.85-1.07]). Similar interactions between SPAN-100 index status and thrombolysis treatment were observed for the 2 secondary outcomes. CONCLUSION AND RELEVANCE Compared with the SPAN-100-negative patients with AIS, the SPAN-100-positive patients with AIS seem to have poorer 3-month outcomes but may derive greater benefit when treated with intravenous thrombolysis. The SPAN-100-positive patients are often excluded from AIS clinical trials but should probably not be denied thrombolysis treatment on the basis of such a profile alone.
    05/2014; 71(7). DOI:10.1001/jamaneurol.2014.689
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    ABSTRACT: The aim of this updated guideline is to provide comprehensive and timely evidence-based recommendations on the prevention of future stroke among survivors of ischemic stroke or transient ischemic attack. The guideline is addressed to all clinicians who manage secondary prevention for these patients. Evidence-based recommendations are provided for control of risk factors, intervention for vascular obstruction, antithrombotic therapy for cardioembolism, and antiplatelet therapy for noncardioembolic stroke. Recommendations are also provided for the prevention of recurrent stroke in a variety of specific circumstances, including aortic arch atherosclerosis, arterial dissection, patent foramen ovale, hyperhomocysteinemia, hypercoagulable states, antiphospholipid antibody syndrome, sickle cell disease, cerebral venous sinus thrombosis, and pregnancy. Special sections address use of antithrombotic and anticoagulation therapy after an intracranial hemorrhage and implementation of guidelines.
    Stroke 05/2014; 45(7). DOI:10.1161/STR.0000000000000024 · 6.02 Impact Factor
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    ABSTRACT: Background Treatment with the combination of clopidogrel and aspirin taken soon after a transient ischemic attack (TIA) or minor stroke was shown to reduce the 90‐day risk of stroke in a large trial in China, but the cost‐effectiveness is unknown. This study sought to estimate the cost‐effectiveness of the clopidogrel‐aspirin regimen for acute TIA or minor stroke. Methods and Results A Markov model was created to determine the cost‐effectiveness of treatment of acute TIA or minor stroke patients with clopidogrel‐aspirin compared with aspirin alone. Inputs for the model were obtained from clinical trial data, claims databases, and the published literature. The main outcome measure was cost per quality‐adjusted life‐years (QALYs) gained. One‐way and multivariable probabilistic sensitivity analyses were performed to test the robustness of the findings. Compared with aspirin alone, clopidogrel‐aspirin resulted in a lifetime gain of 0.037 QALYs at an additional cost of CNY 1250 (US$ 192), yielding an incremental cost‐effectiveness ratio of CNY 33 800 (US$ 5200) per QALY gained. Probabilistic sensitivity analysis showed that clopidogrel‐aspirin therapy was more cost‐effective in 95.7% of the simulations at a willingness‐to‐pay threshold recommended by the World Health Organization of CNY 105 000 (US$ 16 200) per QALY. Conclusions Early 90‐day clopidogrel‐aspirin regimen for acute TIA or minor stroke is highly cost‐effective in China. Although clopidogrel is generic, Plavix is brand in China. If Plavix were generic, treatment with clopidogrel‐aspirin would have been cost saving.
    Journal of the American Heart Association 04/2014; 3(3). DOI:10.1161/JAHA.114.000912 · 2.88 Impact Factor
  • Kevin Grumbach, Catherine R Lucey, S Claiborne Johnston
    JAMA The Journal of the American Medical Association 03/2014; 311(11):1109-1110. DOI:10.1001/jama.2014.705 · 30.39 Impact Factor
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    Clinical and Translational Science 03/2014; 7(2). DOI:10.1111/cts.12147 · 2.11 Impact Factor

Publication Stats

14k Citations
3,080.34 Total Impact Points

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  • 2014–2015
    • University of Texas at Austin
      Austin, Texas, United States
  • 2012–2014
    • University of Toronto
      • • Division of Neurology
      • • Institute of Health Policy, Management and Evaluation
      Toronto, Ontario, Canada
    • Kaiser Permanente
      Oakland, California, United States
  • 2–2014
    • University of California, San Francisco
      • • Department of Neurology
      • • Division of Hospital Medicine
      • • Department of Medicine
      • • Department of Epidemiology and Biostatistics
      San Francisco, California, United States
  • 2006–2007
    • University of Pittsburgh
      Pittsburgh, Pennsylvania, United States
    • Cleveland Clinic
      Cleveland, Ohio, United States
  • 2005–2006
    • Harbor-UCLA Medical Center
      Torrance, California, United States