Summary The methods and results of health research are documented in study protocols, full study reports (detailing all analyses), journal reports, and participant-level datasets. However, protocols, ...full study reports, and participant-level datasets are rarely available, and journal reports are available for only half of all studies and are plagued by selective reporting of methods and results. Furthermore, information provided in study protocols and reports varies in quality and is often incomplete. When full information about studies is inaccessible, billions of dollars in investment are wasted, bias is introduced, and research and care of patients are detrimentally affected. To help to improve this situation at a systemic level, three main actions are warranted. First, academic institutions and funders should reward investigators who fully disseminate their research protocols, reports, and participant-level datasets. Second, standards for the content of protocols and full study reports and for data sharing practices should be rigorously developed and adopted for all types of health research. Finally, journals, funders, sponsors, research ethics committees, regulators, and legislators should endorse and enforce policies supporting study registration and wide availability of journal reports, full study reports, and participant-level datasets.
H. Bart van der Worp and colleagues discuss the controversies and possibilities of translating the results of animal experiments into human clinical trials.
The consolidation of scientific knowledge proceeds through the interpretation and then distillation of data presented in research reports, first in review articles and then in textbooks and ...undergraduate courses, until truths become accepted as such both amongst "experts" and in the public understanding. Where data are collected but remain unpublished, they cannot contribute to this distillation of knowledge. If these unpublished data differ substantially from published work, conclusions may not reflect adequately the underlying biological effects being described. The existence and any impact of such "publication bias" in the laboratory sciences have not been described. Using the CAMARADES (Collaborative Approach to Meta-analysis and Review of Animal Data in Experimental Studies) database we identified 16 systematic reviews of interventions tested in animal studies of acute ischaemic stroke involving 525 unique publications. Only ten publications (2%) reported no significant effects on infarct volume and only six (1.2%) did not report at least one significant finding. Egger regression and trim-and-fill analysis suggested that publication bias was highly prevalent (present in the literature for 16 and ten interventions, respectively) in animal studies modelling stroke. Trim-and-fill analysis suggested that publication bias might account for around one-third of the efficacy reported in systematic reviews, with reported efficacy falling from 31.3% to 23.8% after adjustment for publication bias. We estimate that a further 214 experiments (in addition to the 1,359 identified through rigorous systematic review; non publication rate 14%) have been conducted but not reported. It is probable that publication bias has an important impact in other animal disease models, and more broadly in the life sciences.
Summary A fifth of all strokes and transient ischaemic attacks occur in the posterior circulation arterial territory. Diagnosis can be challenging, in part because of substantial overlap in symptoms ...and signs with ischaemia in the anterior circulation. Improved methods of non-invasive imaging of the vertebrobasilar arterial tree have been used in recent prospective follow-up studies, which have shown a high risk of early recurrent stroke, particularly when there is associated vertebrobasilar stenosis. This finding emphasises the importance of urgent secondary prevention, and the role of stenting for vertebral stenosis is being investigated.
Pioglitazone targets multiple pathogenic pathways involved in the development of cardiovascular diseases (CVD). The aim of this systematic review and meta-analysis is to assess the effects of ...pioglitazone treatment on the secondary prevention of CVD.
Randomized-controlled trials of pioglitazone in patients with CVD were identified through PubMed, Embase, Cochrane and CINAHL, in a search up to May 2016. Studies were included if pioglitazone was compared with any control (usual care, placebo or active comparator) and if patients were previously diagnosed with CVD. The outcomes of interest included major adverse cardiovascular events (MACE), myocardial infarction (MI), stroke, all-cause mortality and heart failure (HF). All outcomes were compared by pooled risk ratios (RR) with a 95% confidence interval (CI). Pooled estimates were calculated using a random-effects model.
Ten studies reported the effects of pioglitazone on any of the outcomes of interest. Pioglitazone reduced recurrent MACE (RR 0.74, 95% 0.60-0.92; I
= 35), MI (RR 0.77, 95% CI 0.64-0.93; I
= 0%), or stroke (RR 0.81, 95% CI 0.68-0.96; I
= 0%). Pioglitazone did not reduce all-cause mortality (RR 0.94, 95% CI 0.81-1.08; I
= 0%), whereas pioglitazone treatment was associated with an increased risk of HF (RR 1.33, 95% CI 1.14-1.54).
Pioglitazone lowers the risk of recurrent MACE, stroke, or MI in patients with clinical manifest vascular disease. Pioglitazone does not lower the risk for all-cause mortality, and increases the risk for the development of HF.
Abstract Background Brain lesions on diffusion-weighted imaging (DWI) are frequently found after carotid artery stenting (CAS), but their clinical relevance remains unclear. Objectives This study ...sought to investigate whether periprocedural ischemic DWI lesions after CAS or carotid endarterectomy (CEA) are associated with an increased risk of recurrent cerebrovascular events. Methods In the magnetic resonance imaging (MRI) substudy of ICSS (International Carotid Stenting Study), 231 patients with symptomatic carotid stenosis were randomized to undergo CAS (n = 124) or CEA (n = 107). MRIs were performed 1 to 7 days before and 1 to 3 days after treatment. The primary outcome event was stroke or transient ischemic attack in any territory occurring between the post-treatment MRI and the end of follow-up. Time to occurrence of the primary outcome event was compared between patients with (DWI+) and without (DWI–) new DWI lesions on the post-treatment scan in the CAS and CEA groups separately. Results Median time of follow-up was 4.1 years (interquartile range: 3.0 to 5.2). In the CAS group, recurrent stroke or transient ischemic attack occurred more often among DWI+ patients (12 of 62) than among DWI– patients (6 of 62), with a cumulative 5-year incidence of 22.8% (standard error SE: 7.1%) and 8.8% (SE: 3.8%), respectively (unadjusted hazard ratio: 2.85; 95% confidence interval: 1.05 to 7.72; p = 0.04). In DWI+ and DWI– patients, 8 and 2 events, respectively, occurred within 6 months after treatment. In the CEA group, there was no difference in recurrent cerebrovascular events between DWI+ and DWI– patients. Conclusions Ischemic brain lesions discovered on DWI after CAS seem to be a marker of increased risk for recurrent cerebrovascular events. Patients with periprocedural DWI lesions might benefit from more aggressive and prolonged antiplatelet therapy after CAS. (A Randomised Comparison of the Risks, Benefits and Cost Effectiveness of Primary Carotid Stenting With Carotid Endarterectomy: International Carotid Stenting Study; ISRCTN25337470 )
Summary Background Stenting is an alternative to endarterectomy for treatment of carotid artery stenosis, but long-term efficacy is uncertain. We report long-term data from the randomised ...International Carotid Stenting Study comparison of these treatments. Methods Patients with symptomatic carotid stenosis were randomly assigned 1:1 to open treatment with stenting or endarterectomy at 50 centres worldwide. Randomisation was computer generated centrally and allocated by telephone call or fax. Major outcomes were assessed by an independent endpoint committee unaware of treatment assignment. The primary endpoint was fatal or disabling stroke in any territory after randomisation to the end of follow-up. Analysis was by intention to treat (ITT all patients) and per protocol from 31 days after treatment (all patients in whom assigned treatment was completed). Functional ability was rated with the modified Rankin scale. This study is registered, number ISRCTN25337470. Findings 1713 patients were assigned to stenting (n=855) or endarterectomy (n=858) and followed up for a median of 4·2 years (IQR 3·0–5·2, maximum 10·0). Three patients withdrew immediately and, therefore, the ITT population comprised 1710 patients. The number of fatal or disabling strokes (52 vs 49) and cumulative 5-year risk did not differ significantly between the stenting and endarterectomy groups (6·4% vs 6·5%; hazard ratio HR 1·06, 95% CI 0·72–1·57, p=0·77). Any stroke was more frequent in the stenting group than in the endarterectomy group (119 vs 72 events; ITT population, 5-year cumulative risk 15·2% vs 9·4%, HR 1·71, 95% CI 1·28–2·30, p<0·001; per-protocol population, 5-year cumulative risk 8·9% vs 5·8%, 1·53, 1·02–2·31, p=0·04), but were mainly non-disabling strokes. The distribution of modified Rankin scale scores at 1 year, 5 years, or final follow-up did not differ significantly between treatment groups. Interpretation Long-term functional outcome and risk of fatal or disabling stroke are similar for stenting and endarterectomy for symptomatic carotid stenosis. Funding Medical Research Council, Stroke Association, Sanofi-Synthélabo, European Union.
The development of stroke drugs has been characterized by success in animal studies and subsequent failure in clinical trials. Animal studies might have overstated efficacy, or clinical trials might ...have understated efficacy; in either case we need to better understand the reasons for failure. Techniques borrowed from clinical trials have recently allowed the impact of publication and study-quality biases on published estimates of efficacy in animal experiments to be described. On the basis of these data, we propose minimum standards for the range and quality of pre-clinical animal data. We believe the adoption of these standards will lead to improved effectiveness and efficiency in the selection of drugs for clinical trials in stroke and in the design of those trials.
Infections complicate the acute phase of stroke in one third of patients and especially pneumonia is associated with increased risk of death or dependency. In randomized trials of stroke patients, ...preventive antibiotics reduced overall infections, but did not reduce pneumonia or improve outcome. This may be explained by broad selection criteria, including many patients with a low risk of pneumonia. To assess the potential of selection of patients at high risk of pneumonia, we performed a post-hoc analysis in the Preventive Antibiotics in Stroke Study (PASS).
PASS was a multicentre phase 3 trial in acute stroke patients who were randomized to preventive ceftriaxone for four days within 24 hours or standard care. For this analysis patients were divided based on the ISAN risk score for pneumonia as follows: low (0-6), medium (7-14) and high (15-21). Primary outcomes were pneumonia rate during admission as judged by the treating physician, and by an independent committee; secondary outcomes were overall infections and unfavorable outcome (modified Rankin Scale ≥3). We adjusted with multivariable regression for possible confounders: age, stroke subtype and severity, pre-stroke dependency and diabetes.
Pneumonia occurred more frequently in higher risk groups (25.7% (high), 9.0% (medium) 1.5%, (low)). The absolute difference in pneumonia rate between patients treated with ceftriaxone or standard care increased with the ISAN score (low: 0.5%, medium: 1.2%, high: 10.1%). After adjustment ceftriaxone reduced overall infections in the low and medium groups, not in the high-risk group. There was a trend towards reduction of pneumonia as judged by the committee (3.7% vs 13.6%, aOR = 0.164, p = 0.063) in the high-risk group.
This post-hoc analysis of PASS confirmed higher rates of pneumonia with higher ISAN scores, and suggests that in acute stroke patients with an ISAN score of ≥15, preventive ceftriaxone for four days may reduce pneumonia rate.
In A Randomized trial of Unruptured Brain Arteriovenous malformations (ARUBA), randomisation was halted at a mean follow-up of 33·3 months after a prespecified interim analysis showed that medical ...management alone was superior to the combination of medical management and interventional therapy in preventing symptomatic stroke or death. We aimed to study whether these differences persisted through 5-years' follow-up.
ARUBA was a non-blinded, randomised trial done at 39 clinical centres in nine countries. Adults (age ≥18 years) diagnosed with an unruptured brain arteriovenous malformation, who had never undergone interventional therapy, and were considered by participating clinical centres to be suitable for intervention to eradicate the lesion, were eligible for inclusion. Patients were randomly assigned (1:1) by a web-based data collection system, stratified by clinical centre in a random permuted block design with block sizes of two, four, and six, to medical management alone or with interventional therapy (neurosurgery, embolisation, or stereotactic radiotherapy, alone or in any combination, sequence, or number). Although patients and investigators at a given centre were not masked to treatment assignment, investigators at other centres and those in the clinical coordinating centre were not informed of assignment or outcomes at any of the centres. The primary outcome was time to death or symptomatic stroke confirmed by imaging, assessed by a neurologist at each centre not involved in the management of participants' care, and monitored by an independent committee using an adaptive approach with interim analyses. Enrolment began on April 4, 2007, and was halted on April 15, 2013, after which follow-up continued until July 15, 2015. All analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, NCT00389181.
Of 1740 patients screened, 226 were randomly assigned to medical management alone (n=110) or medical management plus interventional therapy (n=116). During a mean follow-up of 50·4 months (SD 22·9), the incidence of death or symptomatic stroke was lower with medical management alone (15 of 110, 3·39 per 100 patient-years) than with medical management with interventional therapy (41 of 116, 12·32 per 100 patient-years; hazard ratio 0·31, 95% CI 0·17 to 0·56). Two patients in the medical management group and four in the interventional therapy group (two attributed to intervention) died during follow-up. Adverse events were observed less often in patients allocated to medical management compared with interventional therapy (283 vs 369; 58·97 vs 78·73 per 100 patient-years; risk difference −19·76, 95% CI −30·33 to −9·19).
After extended follow-up, ARUBA showed that medical management alone remained superior to interventional therapy for the prevention of death or symptomatic stroke in patients with an unruptured brain arteriovenous malformation. The data concerning the disparity in outcomes should affect standard specialist practice and the information presented to patients. The even longer-term risks and differences between the two therapeutic approaches remains uncertain.
National Institute of Neurological Disorders and Stroke for the randomisation phase and Vital Projects Fund for the follow-up phase.
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