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Biomedical subjects

S Claiborne Johnston

Publications and source records attributed to S Claiborne Johnston.

At least 19 recordsLinked to original sources
PubMed2006

Why are eligible thrombolysis candidates left untreated?

BACKGROUND: Despite proven efficacy, thrombolytics are used in a minority of eligible candidates. Because some of the exclusion criteria are vague, relying on documented contraindications could disguise biases in usage. This study sought to identify barriers to tissue-type plasminogen activator (tPA) treatment among eligible patients with acute ischemic stroke. METHODS: The study prospectively identified all patients with an initial diagnosis of ischemic stroke arriving within 2.5 hours of symptom onset at 11 hospitals participating in the Centers for Disease Control and Prevention-sponsored California Acute Stroke Prototype Registry during two 3-month periods in 2002 and 2003. Potential risk factors for nontreatment with thrombolytics among patients categorized as eligible were examined, based on directly documented contraindications. Analyses were repeated after reclassification of eligibility based on record review. RESULTS: Of 625 patients with ischemic stroke, 126 (20%) arrived at the emergency department within 2.5 hours of symptom onset. Based on direct documentation, 72 (11.5% of all patients; 57% of in-time arrivals) were eligible for thrombolysis; 32 (44% of eligible patients) who received tPA within the 3-hour time window and 40 who did not receive thrombolytic medications despite having no documented contraindication to treatment. Factors predictive of nontreatment were older age (p=0.0005), later arrival (p=0.004), and admittance to a non-academic hospital (p=0.03). After record review, slightly fewer patients (n=61) were deemed eligible, with a tPA treatment rate of 52% among those eligible. Older age (p=0.002) and later arrival (p=0.002) continued to be predictive of nontreatment with thrombolytics after reclassification. CONCLUSIONS: Even when more-comprehensive eligibility standards are applied, older age and later hospital arrival are associated with nontreatment with thrombolytics.

Acute Disease↗
PubMed2006

NIH Stroke Scale reliability in ratings from a large sample of clinicians.

OBJECTIVE: The NIH Stroke Scale (NIHSS) is widely used in stroke clinical care and trials. Certification in its use, most commonly through rating of video vignettes, is routinely required. To investigate the reliability of the NIHSS in a representative sample of raters, we examined the results of the most frequently used certification examination. METHODS: At the invitation of the National Stroke Association, we analyzed the results of all raters who completed one of two multiple patient videotaped certification examinations from 1998 to 2004. Total scores for each vignette were calculated and ratings were compared based on percentile of responses and modified kappa scores. RESULTS: There were 7,405 unique raters with 38,148 individual NIHSS item responses; median scores for each vignette ranged from 0 to 31. Total NIHSS scores varied widely between raters; scoring for 7 of the 11 patients (64%) had a four or more point difference in NIHSS score from the 5th to 95th percentile. The aphasia (kappa = 0.60) and facial palsy (0.65) items on the test contributed most to the variance in the total NIHSS score. Nurses agreed with the most common response on scoring more frequently than physicians (p < 0.0001). Taking the certification examination multiple times did not improve agreement. CONCLUSIONS: In a large diverse sample of clinicians, inter-rater reliability for individual elements of the NIHSS on videotaped vignettes was generally good, but overall scoring was inconsistent and could impact clinical trial results. Whether additional training, modification of examination elements, or clearer definitions for scoring could improve reliability requires further study.

Certification↗
PubMed2006

Duration of hospital participation in a nationwide stroke registry is associated with improved quality of care.

BACKGROUND: There are several proven therapies for patients with ischemic stroke or transient ischemic attack (TIA), including prophylaxis of deep venous thrombosis (DVT) and initiation of antithrombotic medications within 48 h and at discharge. Stroke registries have been promoted as a means of increasing use of such interventions, which are currently underutilized. METHODS: From 1999 through 2003, 86 U.S. hospitals participated in Ethos, a voluntary web-based acute stroke treatment registry. Detailed data were collected on all patients admitted with a diagnosis of TIA or ischemic stroke. Rates of optimal treatment (defined as either receipt or a valid contraindication) were examined within each hospital as a function of its length of time in registry. Generalized estimating equations were used to adjust for patient and hospital characteristics. RESULTS: A total of 16,301 patients were discharged with a diagnosis of stroke or TIA from 50 hospitals that participated for more than 1 year. Rates of optimal treatment during the first 3 months of participation were as follows: 92.5% for antithrombotic medication within 48 h, 84.6% for antithrombotic medications at discharge, and 77.1% for DVT prophylaxis. Rates for all treatments improved with duration of participation in the registry (p < 0.05), with the most dramatic improvements in the first year. CONCLUSION: In a large cohort of patients with stroke or TIA, three targeted quality-improvement measures improved among hospitals participating in a disease-specific registry. Although the changes could be attributed to interventions other than the registry, these findings demonstrate the potential for hospital-level interventions to improve care for patients with stroke and TIA.

Cohort Studies↗
PubMed2006

Effect of a US National Institutes of Health programme of clinical trials on public health and costs.

BACKGROUND: Few attempts have been made to estimate the public return on investment in medical research. The total costs and benefits to society of a clinical trial, the final step in testing an intervention, can be estimated by evaluating the effect of trial results on medical care and health. METHODS: All phase III randomised trials funded by the US National Institute of Neurological Disorders and Stroke before Jan 1, 2000, were included. Pertinent publications on use, cost to society, and health effects for each studied intervention were identified by systematic review, supplemented with data from other public and proprietary sources. Regardless of whether a trial was positive or negative, information on use of tested therapies was integrated with published per-use data on costs and health effect (converted to 2004 US dollars) to generate 10-year projections for the US population. FINDINGS: 28 trials with a total cost of 335 million dollars were included. Six trials (21%) resulted in measurable improvements in health, and four (14%) resulted in cost savings to society. At 10 years, the programme of trials resulted in an estimated additional 470,000 quality-adjusted life years at a total cost of 3.6 billion dollars (including costs of all trials and additional health-care and other expenditures). Valuing a quality-adjusted life year at per-head gross domestic product, the projected net benefit to society at 10-years was 15.2 billion dollars. 95% CIs did not include a net loss at 10 years. IMPLICATIONS: For this institute, the public return on investment in clinical trials has been substantial. Although results led to increases in health-care expenditures, health gains were large and valuable.

Biomedical Research↗
PubMed2006

Guidelines for prevention of stroke in patients with ischemic stroke or transient ischemic attack: a statement for healthcare professionals from the American Heart Association/American Stroke Association Council on Stroke: co-sponsored by the Council on Cardiovascular Radiology and Intervention: the American Academy of Neurology affirms the value of this guideline.

The aim of this new statement is to provide comprehensive and timely evidence-based recommendations on the prevention of ischemic stroke among survivors of ischemic stroke or transient ischemic attack. Evidence-based recommendations are included for the control of risk factors, interventional approaches for atherosclerotic disease, antithrombotic treatments for cardioembolism, and the use of antiplatelet agents for noncardioembolic stroke. Further recommendations are provided for the prevention of recurrent stroke in a variety of other specific circumstances, including arterial dissections; patent foramen ovale; hyperhomocysteinemia; hypercoagulable states; sickle cell disease; cerebral venous sinus thrombosis; stroke among women, particularly with regard to pregnancy and the use of postmenopausal hormones; the use of anticoagulation after cerebral hemorrhage; and special approaches for the implementation of guidelines and their use in high-risk populations.

American Heart Association↗
PubMed2006

Clopidogrel and aspirin versus aspirin alone for the prevention of atherothrombotic events.

BACKGROUND: Dual antiplatelet therapy with clopidogrel plus low-dose aspirin has not been studied in a broad population of patients at high risk for atherothrombotic events. METHODS: We randomly assigned 15,603 patients with either clinically evident cardiovascular disease or multiple risk factors to receive clopidogrel (75 mg per day) plus low-dose aspirin (75 to 162 mg per day) or placebo plus low-dose aspirin and followed them for a median of 28 months. The primary efficacy end point was a composite of myocardial infarction, stroke, or death from cardiovascular causes. RESULTS: The rate of the primary efficacy end point was 6.8 percent with clopidogrel plus aspirin and 7.3 percent with placebo plus aspirin (relative risk, 0.93; 95 percent confidence interval, 0.83 to 1.05; P=0.22). The respective rate of the principal secondary efficacy end point, which included hospitalizations for ischemic events, was 16.7 percent and 17.9 percent (relative risk, 0.92; 95 percent confidence interval, 0.86 to 0.995; P=0.04), and the rate of severe bleeding was 1.7 percent and 1.3 percent (relative risk, 1.25; 95 percent confidence interval, 0.97 to 1.61 percent; P=0.09). The rate of the primary end point among patients with multiple risk factors was 6.6 percent with clopidogrel and 5.5 percent with placebo (relative risk, 1.2; 95 percent confidence interval, 0.91 to 1.59; P=0.20) and the rate of death from cardiovascular causes also was higher with clopidogrel (3.9 percent vs. 2.2 percent, P=0.01). In the subgroup with clinically evident atherothrombosis, the rate was 6.9 percent with clopidogrel and 7.9 percent with placebo (relative risk, 0.88; 95 percent confidence interval, 0.77 to 0.998; P=0.046). CONCLUSIONS: In this trial, there was a suggestion of benefit with clopidogrel treatment in patients with symptomatic atherothrombosis and a suggestion of harm in patients with multiple risk factors. Overall, clopidogrel plus aspirin was not significantly more effective than aspirin alone in reducing the rate of myocardial infarction, stroke, or death from cardiovascular causes. (ClinicalTrials.gov number, NCT00050817.).

Adult↗
PubMed2006

Secondary-prevention drug prescription in the very elderly after ischemic stroke or TIA.

BACKGROUND: An age bias may exist in the prescription of important secondary-preventive therapies in the elderly. OBJECTIVE: To evaluate patterns of drug prescription for cardiovascular prevention in the very elderly following hospitalization for an acute ischemic stroke or TIA. METHODS: The authors compared subjects ages > or = 80 with those < 80 in the California Acute Stroke Prototype Registry to evaluate the impact of age on receipt of secondary-prevention medications at the time of hospital discharge. Prespecified secondary-prevention drug classes studied were antithrombotics, lipid-lowering agents, and antihypertensives. RESULTS: Overall, there were 260 patients age > or = 80 and 534 age < 80 admitted with stroke or TIA during the study period. Patients > or = 80 years were less likely to receive actual treatment with antithrombotic medications (p = 0.002) and lipid-lowering medications (p = 0.005) but were more likely to receive antihypertensive medications (p = 0.0007) than their younger counterparts. With regard to optimal treatment (defined as receipt of, or a valid contraindication to, treatment in each category), those > or = 80 were equally likely to receive antithrombotic medications and lipid therapy but remained more likely to receive antihypertensive treatment (77.7 vs 67.0%; p = 0.0007). There were no differences in receipt of optimal combination therapy (defined as optimal treatment in all three therapeutic classes) between patient age groups, even when adjusted for medical history. CONCLUSION: After hospitalization for stroke or TIA, no differences in overall optimal treatment prescription of secondary-prevention medications between patients ages > or = 80 and their younger counterparts were observed.

Age Factors↗
PubMed2006

Reasons why few patients with acute stroke receive tissue plasminogen activator.

Despite the US Food and Drug Administration's approval in 1996, tissue plasminogen activator (tPA) therapy for acute ischemic stroke remains substantially underused. We reviewed 3 potential reasons for low rates of tPA use: poor patient education, physicians' perceived risk of legal liability from negative patient outcomes, and insufficient reimbursement. The recent addition of diagnosis-related grouping code 559 will provide higher payment for stroke patients treated with tPA, creating a natural experiment to examine our third reason.

Drug Utilization↗
PubMed2006

National Stroke Association guidelines for the management of transient ischemic attacks.

OBJECTIVE: Transient ischemic attacks are common and important harbingers of subsequent stroke. Management varies widely, and most published guidelines have not been updated in several years. We sought to create comprehensive, unbiased, evidence-based guidelines for the management of patients with transient ischemic attacks. METHODS: Fifteen expert panelists were selected based on objective criteria, using publication metrics that predicted nomination by practitioners in the field. Prior published guidelines were identified through systematic review, and recommendations derived from them were rated independently for quality by the experts. Highest quality recommendations were selected and subsequently edited by the panelists using a modified Delphi approach with multiple iterations of questionnaires to reach consensus on new changes. Experts were provided systematic reviews of recent clinical studies and were asked to justify wording changes based on new evidence and to rate the final recommendations based on level of evidence and quality. No expert was allowed to contribute to recommendations on a topic for which there could be any perception of a conflict of interest. RESULTS: Of 257 guidelines documents identified by systematic review, 13 documents containing 137 recommendations met all entry criteria. Six iterations of questionnaires were required to reach consensus on wording of 53 final recommendations. Final recommendations covered initial management, evaluation, medical treatment, surgical treatment, and risk factor management. INTERPRETATION: The final recommendations on the care of patients with transient ischemic attacks emphasize the importance of urgent evaluation and treatment. The novel approach used to develop these guidelines is feasible, allows for rapid updating, and may reduce bias.

Health Planning Guidelines↗
PubMed2006

Recombinant therapeutics: from bench to bedside (if your health plan concurs).

A talented medical student at our institution was recently diagnosed with multiple sclerosis (MS). beta interferon was prescribed; however, her annual cap from student health insurance coverage for outpatient drug expenses is only Dollars 3000, a sum that would be exceeded within 3 months and leave her without coverage for symptomatic medications also required for her care. Unable to pay for the treatment from personal resources, she qualified to receive beta interferon without cost from a universal access program established by the manufacturer. Unfortunately, it was evident within a few months that she had a poor therapeutic response, so her physician prescribed natalizumab. Her health care plan requires that infusion therapy be given at the hospital's infusion center, yet for various reasons, the drug was not yet approved by the formulary. She remains unable to receive the drug.

Antibodies, Monoclonal↗
PubMed2006

Financial anatomy of neuroscience research.

OBJECTIVE: To estimate the level of funding for neuroscience research from federal and industry sources and to examine the therapeutic advances in the neurosciences over the past decade. METHODS: We examined financing for neuroscience research over the past decade from the following principal sponsors of biomedical research: the National Institutes of Health, the pharmaceutical industry, large biotechnology firms, and large medical device firms. We also examined US Food and Drug Administration approvals for new molecular entities and medical devices for indications within the neurosciences. Neuroscience was defined to include funding and approvals for neurological and psychiatric conditions. RESULTS: Total (nominal) industry and government funding for neuroscience research increased from $4.8 billion in 1995 to $14.1 billion in 2005 and doubled after adjusting for inflation. In 2005, the pharmaceutical industry and the largest biotechnology and medical device firms accounted for 58% of total funding. The US Food and Drug Administration approved 40 new molecular entities for indications within the neurosciences from 1995 to 2005, with the annual number of approvals remaining relatively stagnant during this period. From 1995 to 2005, the US Food and Drug Administration also approved 1,679 medical devices in the neurosciences for use. INTERPRETATION: Financing for neuroscience research has increased significantly over the past decade, but new approvals for drugs in the neurosciences have not kept pace with the rapid increase in funding. This lag may represent a natural delay in realizing the return in the investment in scientific research or a decline in the productivity of neuroscience research.

Animals↗
PubMed2006

Lipid assessment and treatment patterns in hospitalized TIA and ischemic stroke patients.

BACKGROUND: Identification of dyslipidemia and treatment with lipid-lowering agents are established targets for quality performance during hospitalization for ischemic stroke and transient ischemic attack (TIA). We aimed to study the frequency and predictors of lipid assessment and discharge utilization of lipid-lowering therapies among patients hospitalized for stroke and TIA. METHODS: Demographics, clinical findings, and laboratory data were documented as part of the California Acute Stroke Prototype Registry (CASPR). Frequency of low-density lipoprotein cholesterol (LDL-C) testing and the frequency and appropriate use of lipid-lowering treatment according to national cholesterol guidelines were determined. Multivariate models were generated to determine the contribution of clinical variables to LDL testing and prescription of lipid-lowering medications at discharge. RESULTS: Data were collected on 764 consecutive patients with ischemic stroke or TIA treated at 11 hospitals over a 2-year period. LDL-C measurements were performed in only 50.1% during hospitalization. Measurement of LDL-C was most strongly and independently associated with diagnosis of ischemic stroke (vs. TIA, P = .02) and history of dyslipidemia (P = .05). Overall, 48.4% of the CASPR cohort received lipid-lowering medications at discharge. Independent predictors for being prescribed lipid-lowering agents at discharge were diagnosis of ischemic stroke (P = .0009), LDL-C testing (P = .0002), high risk of future coronary events according to national guidelines (P = .02), and history of dyslipidemia (P< .0001). Only 59% of patients at high risk for future coronary events were discharged on a lipid-lowering medication. CONCLUSIONS: Serum cholesterol testing and treatment are underutilized during hospitalization for ischemic stroke or TIA.

Aged↗
PubMed2006

Recent advances in management of transient ischaemic attacks and minor ischaemic strokes.

The risk of recurrent stroke during the first few days after a transient ischaemic attack or minor stroke is much higher than previously estimated. However, there is substantial variation worldwide in how patients with suspected transient ischaemic attack or minor stroke are investigated and treated in the acute phase: some health-care systems provide immediate emergency inpatient care and others provide non-emergency outpatient clinical assessment. This review considers what is known about the early prognosis after transient ischaemic attack and minor ischaemic stroke, what factors identify individuals at particularly high early risk of stroke, and what evidence there is that urgent preventive treatment is likely to be effective in reducing the early risk of stroke.

Humans↗