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Biomedical subjects

Devin L Brown

Publications and source records attributed to Devin L Brown.

12 recordsLinked to original sources

Screening for obstructive sleep apnea in stroke patients: a cost-effectiveness analysis.

BACKGROUND AND PURPOSE: Obstructive sleep apnea (OSA) is common after acute ischemic stroke and predicts poor stroke recovery, but whether screening for OSA and treatment by continuous positive airway pressure (CPAP) improves neurological outcome is unknown. We used a cost-effectiveness model to estimate the magnitude of benefit that would be necessary to make polysomnography (PSG) and OSA treatment cost-effective in stroke patients. METHODS: A decision tree modeled 2 alternative strategies: PSG followed by 3 months of CPAP for those found to have OSA versus no screening. The primary outcome was the utility gained through OSA screening and treatment in relation to 2 common willingness-to-pay thresholds of $50,000 and $100,000 per quality-adjusted life year (QALY). RESULTS: Screening resulted in an incremental cost-effectiveness ratio of $49,421 per QALY. Screening is cost-effective as long as the treatment of stroke patients with OSA by CPAP improves patient utilities by >0.2 for a willingness-to-pay of $50,000 per QALY and 0.1 for a willingness-to-pay of $100,000 per QALY. CONCLUSIONS: A clinical trial assessing the effectiveness of CPAP in improving stroke outcome is warranted from a cost-effectiveness standpoint.

Cost-Benefit Analysis↗

Recurrent stroke risk is higher than cardiac event risk after initial stroke/transient ischemic attack.

BACKGROUND AND PURPOSE: Patients with ischemic stroke and transient ischemic attack (TIA) are at risk for recurrent cerebrovascular and cardiac events. Understanding which of these adverse events is more likely to occur next is instructive for preventive therapy planning. METHODS: Subjects (n=1923) were identified from a sample of hospital discharges from administrative claims for the Michigan Medicare population from January 2001 to June 2001 using International Classification of Diseases, 9th Revision codes for ischemic stroke/TIA. Outcomes (cardiac events, myocardial infarction [MI], percutaneous transluminal coronary angioplasty [PTCA], coronary artery bypass grafting [CABG] and ischemic strokes) were identified for 2001 to 2003. Comparison between cardiac and stroke as secondary events were made using cumulative incidence estimates. RESULTS: Over the follow-up period, 172 patients had a cardiac event (62.8% MI, 7.6% CABG, 14.5% PTCA, 9.3% MI and PTCA, and 5.8% MI and CABG) and 239 had a stroke as their first event. Cardiac event at 2 years had occurred in 7.7%, and stroke occurred in 11.8%. CONCLUSIONS: The risk of stroke after initial stroke/TIA is higher than the risk of cardiac events. The propensity after stroke/TIA to have the first recurrent ischemic event in the brain, rather than in the heart, has implications for prophylactic therapy selection.

Aged↗

Gavestinel does not improve outcome after acute intracerebral hemorrhage: an analysis from the GAIN International and GAIN Americas studies.

BACKGROUND AND PURPOSE: Glycine Antagonist in Neuroprotection (GAIN) International and GAIN Americas trials were prospectively designed, randomized, placebo-controlled trials of gavestinel, a glycine-site antagonist and putative neuroprotectant drug administered within 6 hours of suspected ischemic or hemorrhagic stroke. Both trials reported that gavestinel was ineffective in ischemic stroke. This analysis reports the results in those with primary intracerebral hemorrhage. METHODS: The primary hypothesis was that gavestinel treatment did not alter outcome, measured at 3 months by the Barthel Index (BI), from acute intracerebral hemorrhage, based on pooled results from both trials. The BI scores were divided into 3 groups: 95 to 100 (independent), 60 to 90 (assisted independence), and 0 to 55 (dependent) or dead. RESULTS: In total, 3450 patients were randomized in GAIN International (N=1804) and GAIN Americas (N=1646). Of these, 571 were ultimately identified to have spontaneous intracerebral hematoma on baseline head computerized tomography scan. The difference in distribution of trichotomized BI scores at 3 months between gavestinel and placebo was not statistically significant (P=0.09). Serious adverse events were reported at similar rates in the 2 treatment groups. CONCLUSIONS: These observations from the combined GAIN International and GAIN Americas trials suggest that gavestinel is not of substantial benefit or harm to patients with primary intracerebral hemorrhage. These findings are similar to results previously reported in patients with ischemic stroke.

Acute Disease↗

Survey of emergency physicians about recombinant tissue plasminogen activator for acute ischemic stroke.

STUDY OBJECTIVE: The use of recombinant tissue plasminogen activator (rt-PA) for acute ischemic stroke is controversial among emergency physicians. We survey emergency physicians to determine (1) the proportion of emergency physicians resistant to using rt-PA in the ideal setting because of the risk of symptomatic intracerebral hemorrhage; (2) the proportion of emergency physicians resistant to using rt-PA in the ideal setting because of the perceived lack of benefit; (3) the highest acceptable symptomatic intracerebral hemorrhage risk; and (4) the lowest acceptable accompanying relative improvement in neurologic outcome. METHODS: The American College of Emergency Physicians randomly selected 2,600 of its active members for anonymous Web-based or paper survey. The proportion of ED physicians resistant to rt-PA use because of symptomatic intracerebral hemorrhage risk and perceived lack of benefit, in addition to the mean acceptable symptomatic intracerebral hemorrhage risk and associated benefit, was calculated with 95% confidence intervals (CIs). Multivariable logistic regression was used to identify factors independently associated with willingness to use rt-PA in the ideal setting. RESULTS: The median age of the 1,105 (43%) respondents was 44 years. Overall, the mean upper limit of symptomatic intracerebral hemorrhage tolerable was 3.4% (95% CI 3.2% to 3.5%), with associated lowest acceptable mean relative improvement of 40% (95% CI 39% to 41%). Forty percent (95% CI 37% to 44%) of physicians reported that they were not likely to use rt-PA. Of these, 65% (95% CI 61% to 69%) of physicians reported this was because of the risk of symptomatic intracerebral hemorrhage, 23% (95% CI 19% to 27%) reported the cause was the perceived lack of benefit, and 12% (95% CI 9% to 15%) reported both reasons were the cause. Independently associated with willingness to use rt-PA were female sex (odds ratio 2.30 [1.57, 3.36]) and previous use of rt-PA for stroke (3.13 [2.33, 4.17]). CONCLUSION: Symptomatic intracerebral hemorrhage risk is the factor most likely to preclude rt-PA use by emergency physicians. Of the 40% of physicians who would not use rt-PA, about two thirds reported this was due to symptomatic intracerebral hemorrhage risk, and about a quarter of physicians cited the relative lack of benefit. Treatment trials that aim to reduce symptomatic intracerebral hemorrhage risk to 2% to 3% are likely to stimulate the interest of emergency physicians in the use of thrombolytics for acute ischemic stroke.

Acute Disease↗

Excess stroke in Mexican Americans compared with non-Hispanic Whites: the Brain Attack Surveillance in Corpus Christi Project.

Mexican Americans are the largest subgroup of Hispanics, the largest minority population in the United States. Stroke is the leading cause of disability and third leading cause of death. The authors compared stroke incidence among Mexican Americans and non-Hispanic Whites in a population-based study. Stroke cases were ascertained in Nueces County, Texas, utilizing concomitant active and passive surveillance. Cases were validated on the basis of source documentation by board-certified neurologists masked to subjects' ethnicity. From January 2000 to December 2002, 2,350 cerebrovascular events occurred. Of the completed strokes, 53% were in Mexican Americans. The crude cumulative incidence was 168/10,000 in Mexican Americans and 136/10,000 in non-Hispanic Whites. Mexican Americans had a higher cumulative incidence for ischemic stroke (ages 45-59 years: risk ratio = 2.04, 95% confidence interval: 1.55, 2.69; ages 60-74 years: risk ratio = 1.58, 95% confidence interval: 1.31, 1.91; ages >or=75 years: risk ratio = 1.12, 95% confidence interval: 0.94, 1.32). Intracerebral hemorrhage was more common in Mexican Americans (age-adjusted risk ratio = 1.63, 95% confidence interval: 1.24, 2.16). The subarachnoid hemorrhage age-adjusted risk ratio was 1.57 (95% confidence interval: 0.86, 2.89). Mexican Americans experience a substantially greater ischemic stroke and intracerebral hemorrhage incidence compared with non-Hispanic Whites. As the Mexican-American population grows and ages, measures to target this population for stroke prevention are critical.

Age Distribution↗

Do gender and race impact the use of antithrombotic therapy in patients with stroke/TIA?

The authors examined the relationships between sex and race and antithrombotics prescribed at discharge in the Michigan Medicare population using retrospective medical record abstraction (n = 2,715) for the period January 1, 2001, to June 30, 2001. There were no differences in the use of antithrombotics at discharge by race or sex and no differences in the prescribing of aspirin, warfarin, aspirin/extended release dipyridamole, or clopidogrel by race or sex after adjustment for confounders.

Black or African American↗

Stroke risk after transient ischemic attack in a population-based setting.

BACKGROUND AND PURPOSE: Stroke risk after transient ischemic attack (TIA) has not been examined in an ethnically diverse population-based community setting. The purpose of this study was to identify stroke risk among TIA patients in a population-based cerebrovascular disease surveillance project. METHODS: The Brain Attack Surveillance in Corpus Christi (BASIC) Project prospectively ascertains stroke and TIA cases in a geographically isolated Southeast Texas County. The community is approximately half Mexican American and half nonHispanic white. Cases are validated by board-certified neurologists using source documentation. Cumulative risk for stroke after TIA was determined using Kaplan-Meier estimates. Cox proportional hazards regression was used to test for associations between stroke risk after TIA and demographics, symptoms, risk factors, and history of stroke/TIA. RESULTS: BASIC identified 612 TIA cases between January 1, 2000, and December 31, 2002; 60.9% were female and 48.0% were Mexican American. Median age was 73.8 years. Stroke risk within 2 days, 7 days, 30 days, 90 days, and 12 months was 1.64%, 1.97%, 3.15%, 4.03%, and 7.27%, respectively. Stroke risk was not influenced by ethnicity, symptoms, or risk factors. CONCLUSIONS: Using a population-based design, we found that early stroke risk after TIA was less than previously reported in this bi-ethnic population of Mexican Americans and nonHispanic whites. Approximately half of the 90-day stroke risk after TIA occurred within 2 days.

Aged↗

Predicting major neurological improvement with intravenous recombinant tissue plasminogen activator treatment of stroke.

BACKGROUND AND PURPOSE: In the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA Stroke Study, major neurological improvement within 24 hours (MNI) occurred significantly more frequently with recombinant tissue plasminogen activator (rtPA) treatment than with placebo. We explored the relationship between MNI and 3-month favorable outcome and sought clinical predictors of MNI. METHODS: Data from 312 rtPA-treated patients from the NINDS trial were used to assess the ability of MNI to predict favorable outcome at 3 months as defined by a modified Rankin Scale score of 0 to 1. Next, a multivariable predictive model was developed for MNI within the same data set. Clinical variables examined included age, time to treatment (TTT), diabetes, pretreatment glucose, baseline National Institutes of Health Stroke Scale score, pretreatment blood pressure, history of atrial fibrillation, weight >100 kg, and a dense artery sign. Finally, this model was used to forecast into the placebo group of the NINDS trial to assess the uniqueness of the predictors in the rtPA-treated group. RESULTS: MNI had a positive predictive value and negative predictive value of 0.70 for predicting favorable 3-month outcome. Only age [odds ratio (OR), 0.68; 95% confidence interval (CI), 0.47 to 0.99] and TTT (OR, 0.56; 95% CI, 0.34 to 0.91) appear to be independently associated with MNI. The model performed only moderately well (area under the receiver-operating characteristic curve, 0.66). Age (OR, 0.67; 95% CI, 0.45 to 0.99) but not TTT was associated with MNI in the placebo group. CONCLUSIONS: MNI may be a useful surrogate for thrombolytic activity and is predictive of favorable 3-month outcome. When rates of MNI in different populations of stroke patients treated with thrombolysis are compared, adjustments for age and TTT may be necessary.

Age Factors↗

Post-emergency department management of stroke.

All stroke patients ideally should be admitted to a stroke unit in which personnel are familiar with strategies for taking care of stroke patients. Prevention of worsening cerebral ischemia by appropriate blood pressure and serum glucose management, fever control, and supplemental oxygen for hypoxemic patients is recommended. Recognition of common complications, such as aspiration pneumonia and deep venous thrombosis, highlights the need for swallowing evaluation and the use of pneumatic compression devices or subcutaneous heparin. Patients should be monitored closely for deterioration in their neurologic status and should have complications appropriately addressed. After evaluation of stroke etiology, appropriate secondary stroke prophylaxis should be selected and initiated before hospital discharge.

Humans↗

Spouses and unrelated friends of probands as controls for stroke genetics studies.

To plan a multisite, ischemic stroke genetic study, stroke patients were surveyed about the availability and characteristics of a convenience sample of spouse/friend controls. 65% of all stroke-affected probands reported a living spouse. A more detailed survey was conducted at the University of Virginia, Charlottesville, Va., USA: 51% of stroke patients reported a living, stroke-free spouse who would be willing to serve as a control, and 49% reported having a stroke-free friend who would be willing to serve as a control. Overall, 75% of stroke patients reported at least 1 individual willing to participate as a control. Cases without an identified control were more likely to be non-white (48%) than were cases with a control (13%; p = 0.00004). Cases were older than controls (67.3 vs. 59.2 years; p = 0.000002), and a greater proportion of cases than controls were male (57 vs. 33%; p = 0.0002). Without proper attention to matching, the use of a spouse/friend convenience sample would result in imbalances in basic demographic characteristics.

Adult↗