Browsing by Author "Menon, Bijoy K"

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    A comparison of meta-analytic methods for synthesizing evidence from explanatory and pragmatic trials
    (2018-01-25) Sajobi, Tolulope T; Li, Guowei; Awosoga, Oluwagbohunmi; Wang, Meng; Menon, Bijoy K; Hill, Michael D; Thabane, Lehana
    Abstract Background The pragmatic–explanatory continuum indicator summary version 2 (PRECIS-2) tool has recently been developed to classify randomized clinical trials (RCTs) as pragmatic or explanatory based on their design characteristics. Given that treatment effects in explanatory trials may be greater than those obtained in pragmatic trials, conventional meta-analytic approaches may not accurately account for the heterogeneity among the studies and may result in biased treatment effect estimates. This study investigates if the incorporation of PRECIS-2 classification of published trials can improve the estimation of overall intervention effects in meta-analysis. Methods Using data from 31 published trials of intervention aimed at reducing obesity in children, we evaluated the utility of incorporating PRECIS-2 ratings of published trials into meta-analysis of intervention effects in clinical trials. Specifically, we compared random-effects meta-analysis, stratified meta-analysis, random-effects meta-regression, and mixture random-effects meta-regression methods for estimating overall pooled intervention effects. Results Our analyses revealed that mixture meta-regression models that incorporate PRECIS-2 classification as covariate resulted in a larger pooled effect size (ES) estimate (ES = − 1.01, 95%CI = [− 1.52, − 0.43]) than conventional random-effects meta-analysis (ES = − 0.15, 95%CI = [− 0.23, − 0.08]). Conclusions In addition to the original intent of PRECIS-2 tool of aiding researchers in their choice of trial design, PRECIS-2 tool is useful for explaining between study variations in systematic review and meta-analysis of published trials. We recommend that researchers adopt mixture meta-regression methods when synthesizing evidence from explanatory and pragmatic trials.
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    Minimal sufficient balance randomization for sequential randomized controlled trial designs: results from the ESCAPE trial
    (2017-11-02) Sajobi, Tolulope T; Singh, Gurbakhshash; Lowerison, Mark W; Engbers, Jordan; Menon, Bijoy K; Demchuk, Andrew M; Goyal, Mayank; Hill, Michael D
    Abstract Background We describe the implementation of minimal sufficient balance randomization, a covariate-adaptive randomization technique, used for the “Endovascular treatment for Small Core and Anterior circulation Proximal occlusion with Emphasis on minimizing CT to recanalization times” (ESCAPE) trial. Methods The ESCAPE trial is a prospective, multicenter, randomized clinical trial that enrolled subjects with the following main inclusion criteria: less than 12 h from symptom onset, age 18 years or older, baseline NIHSS score > 5, ASPECTS score > 5 and computed tomography angiography (CTA) evidence of carotid T/L or M1-segment middle cerebral artery (MCA) occlusion, and at least moderate collaterals by CTA. Patients were randomized using a real-time, dynamic, Internet-based, minimal sufficient balance randomization method that balanced the study arms with respect to baseline covariates including age, sex, baseline NIHSS score, site of arterial occlusion, baseline ASPECTS score and treatment with intravenously administered alteplase. Results Permutation-based tests of group differences confirmed group balance across several baseline covariates including sex (p = 1.00), baseline NIHSS score (p = 0.95), site of arterial occlusion (p = 1.00), baseline ASPECTS score (p = 0.28), treatment with intravenously administered alteplase (p = 0.31), and age (p = 0.67). Conclusion Results from the ESCAPE trial demonstrate the feasibility and the benefit of this covariate adaptive randomization scheme in small-sample trials and for data monitoring endeavors. Trial registration ESCAPE trial – NCT01778335 – at www.clinicaltrials.gov . Registered on 29 January 2013.
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    Multimodality CT based imaging to determine clot characteristics and recanalization with intravenous tPA in patients with acute ischemic stroke
    (2017-02-28) Al-Ajlan, Fahad S; Qazi, Emmad; Kim, Chi K; Venkatesan, E. P; Wilson, Lexi; Menon, Bijoy K
    Abstract Acute ischemic stroke (AIS) is a common neurovascular emergency causing significant burden to society. Currently the main focus of AIS treatment is to restore blood flow to at risk brain tissue. For the last twenty years, intravenous tissue plasminogen activator (tPA) was the only proven therapy for patients with AIS. More recently, five randomized clinical trials established the efficacy of endovascular therapy with or without intravenous tPA in selected patient populations with AIS. Not all stroke patients benefit from intravenous tPA or endovascular treatment. Nonetheless, the concept of early recanalization of occluded arteries resulting in better clinical outcomes is well established. In this focused review, we will discuss how imaging modalities such as Non-Contrast CT, CT-Angiography, and CT-Perfusion can potentially help physicians determine which patients are likely to recanalize early with intravenous tPA and therefore benefit from this therapy.