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To echo Rod’s point, one can also ask if meta-analysis of RCTs is a trial? No, because the meta-analysts had nothing to do with determination of exposure/intervention despite the fact that in each of the trials that were included in MA , it was investigators that determined the exposure/intervention… bd From: Evidence based health (EBH) [mailto:[log in to unmask]] On Behalf Of Rod Jackson Sent: Friday, February 07, 2020 8:55 AM To: [log in to unmask] Subject: Re: Is this a trial? ________________________________ [Attention: This email came from an external source. Do not open attachments or click on links from unknown senders or unexpected emails.] ________________________________ Hi Dan. You don’t need two groups for either a trial or an observational study. It’s all about who determines what exposure/intervention the participants receive. If the investigator does it, then is a trial. If the investigator simply observes what someone else has done (eg. the participant has decided to smoke or the participant’s doctor has decided they should take a drug), it’s an observational study. Just to add another dimension to this discussion, a trial is always longitudinal whereas an observational study can be longitudinal (ie. a cohort study) or cross-sectional (eg. a survey). The reason a trial is always longitudinal is because it starts at the point that the participants are exposed and requires a period of exposure before it is meaningful to measure outcomes. However you can measure both prevalence (a cross-sectional measure of outcomes) as well as incidence (a longitudinal measure of outcomes) in a longitudinal study. For example, at one year after randomizing participants to a new blood pressure lowering drug or an older drug, the investigator could measure blood pressure (a secondary outcome) in all participants. The prim outcome in this study would probably be CVD events over say a 5 year period (an incidence measure). Cheers Rod * * * * * * * * sent from my phone On 8/02/2020, at 04:01, Dan Mayer <[log in to unmask]<mailto:[log in to unmask]>> wrote: My very simplistic definition is that this is NOT a trial. There is only one group, so there is no comparison. Here is the definition from Webster's Dictionary. I see a trial as having two sides whether planned and made up by the researcher (RCT etc) or observed in nature (observational trials of any type as long as there are two sides; intervention and comparison). We can parse out whether an observational study can or should be called a trial, and I do since we decide (consciously and for a hopefully good reason) to observe what happens between two groups. My two cents Best wishes Dan To save this word, you'll needttri·al | \ ˈtrī(-ə)l <https://urldefense.com/v3/__https:/www.merriam-webster.com/login__;!!Fou38LsQmgU!_qcw54WVPzOvaDomGRJdLe4LAEABv1XMjVzZ7PWo1jjAnVR1kdqPXNwJOMeG-t4svQ$> \ Definition of trial (Entry 1 of 3) 1: the formal examination before a competent tribunal of the matter in issue in a civil or criminal cause in order to determine such issue 2a: the action or process of trying or putting to the proof : TEST<https://urldefense.com/v3/__https:/www.merriam-webster.com/dictionary/test__;!!Fou38LsQmgU!_qcw54WVPzOvaDomGRJdLe4LAEABv1XMjVzZ7PWo1jjAnVR1kdqPXNwJOMcXP9LmuQ$> b: a preliminary contest (as in a sport) 3a: a tryout or experiment to test quality, value, or usefulness — compare CLINICAL TRIAL<https://urldefense.com/v3/__https:/www.merriam-webster.com/dictionary/clinical*20trial__;JQ!!Fou38LsQmgU!_qcw54WVPzOvaDomGRJdLe4LAEABv1XMjVzZ7PWo1jjAnVR1kdqPXNwJOMd7eWwNEw$> b: one of a number of repetitions of an experiment 4: a test of faith, patience, or stamina through subjection to suffering or temptationbroadly : a source of vexation or annoyance 5: ATTEMPT<https://urldefense.com/v3/__https:/www.merriam-webster.com/dictionary/attempt__;!!Fou38LsQmgU!_qcw54WVPzOvaDomGRJdLe4LAEABv1XMjVzZ7PWo1jjAnVR1kdqPXNwJOMcY_ylGcw$> On Fri, Feb 7, 2020 at 9:25 AM Tom Jefferson <[log in to unmask]<mailto:[log in to unmask]>> wrote: Hi everyone, I am back asking some more questions on the same topic. I have pasted below the abstract of a study by Trivelato et al (Stroke. 2019;50:00-00. DOI: 10.1161/STROKEAHA.119.025407.) Please take a look and answer my questions: Q3 Would you consider this study a trial? Y/N Q4 Can you give a one line explanation for your choice? To avoid spamming everyone if someone is interested in the study I will send it as a 1 to 1 attachment -------------------------------------------------------------------------------------------------------------------------------------------- Derivo Embolization Device for the Treatment of Intracranial Aneurysms A Multicenter Study of 183 Aneurysms Background and Purpose—Flow diverter technology improvements are necessary to provide safe and good results and enable the treatment of a larger variety of aneurysms. We report a nationwide experience with the Derivo Embolization Device in the treatment of intracranial aneurysms. Methods—BRAIDED (Brazilian Registry of Aneurysms Assigned to Intervention With the Derivo Embolization Device) is a multicenter, prospective, interventional, single-arm trial of the Derivo Embolization Device for the treatment of intracranial aneurysms. The primary effectiveness end point was total aneurysm occlusion at 6- and 12-month angiographies. The secondary safety end point was the absence of serious adverse events during follow-up. Univariable and multivariable logistic regression was performed to identify predictors of aneurysm persistence, periprocedural complications, and adverse events during follow-up. Results—Between December 2016 and October 2018, 146 patients harboring 183 intracranial aneurysms were treated in 151 interventions at 7 centers. Derivo Embolization Device placement was technically successful in all patients. Most aneurysms (86.9%) were located at the internal carotid artery, and the mean diameter was 6.7 mm. At 6 months, 113 of 140 (80.7%) aneurysms met the study’s primary end point, and 74 of 83 (89.2%) met the study’s primary end point at 12 months. Saccular morphology of the aneurysm (odds ratio, 5.66; 95% CI, 1.01–31.77) and the presence of a branch arising from the sac (odds ratio, 6.36; 95% CI, 2.11–22.36) predicted persistence. A long duration of follow-up (odds ratio, 0.86; 95% CI, 0.78–0.95) predicted total occlusion. Of the 146 enrolled patients, 138 (94.5%) were treated without serious adverse events during follow-up. In the multivariable analysis, aneurysms located at a sidewall were less likely to experience these events than those located at bifurcations (odds ratio, 0.07; 95% CI, 0.01–0.51). Conclusions—The Derivo Embolization Device is a safe and effective treatment for intracranial aneurysms. Clinical Trial Registration—URL: http://plataformabrasil.saude.gov.br/login.jsf.<https://urldefense.com/v3/__http:/plataformabrasil.saude.gov.br/login.jsf__;!!Fou38LsQmgU!_qcw54WVPzOvaDomGRJdLe4LAEABv1XMjVzZ7PWo1jjAnVR1kdqPXNwJOMeOaRrHTA$> Unique identifier: CAAE 77089717.7.1001.5125. (Stroke. 2019;50:00-00. DOI: 10.1161/STROKEAHA.119.025407.) Key Words: aneurysm ◼ angiography ◼ Brazil ◼ follow-up studies ◼ humans -------------------------------------------------------------------------------------------------------------------------------------------- Thank you for your interest in this ongoing discussion. Tom. Dr Tom Jefferson Senior Associate Tutor, University of Oxford Researcher, Nordic Cochrane Centre Visiting Professor, Newcastle University ________________________________ To unsubscribe from the EVIDENCE-BASED-HEALTH list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=EVIDENCE-BASED-HEALTH&A=1<https://urldefense.com/v3/__https:/www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=EVIDENCE-BASED-HEALTH&A=1__;!!Fou38LsQmgU!_qcw54WVPzOvaDomGRJdLe4LAEABv1XMjVzZ7PWo1jjAnVR1kdqPXNwJOMcoGOUNpg$> -- Dan Mayer, MD Retired Professor of Emergency Medicine Niskayuna, NY cell: 518-461-3191 ________________________________ To unsubscribe from the EVIDENCE-BASED-HEALTH list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=EVIDENCE-BASED-HEALTH&A=1<https://urldefense.com/v3/__https:/www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=EVIDENCE-BASED-HEALTH&A=1__;!!Fou38LsQmgU!_qcw54WVPzOvaDomGRJdLe4LAEABv1XMjVzZ7PWo1jjAnVR1kdqPXNwJOMcoGOUNpg$> ________________________________ To unsubscribe from the EVIDENCE-BASED-HEALTH list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=EVIDENCE-BASED-HEALTH&A=1<https://urldefense.com/v3/__https:/www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=EVIDENCE-BASED-HEALTH&A=1__;!!Fou38LsQmgU!_qcw54WVPzOvaDomGRJdLe4LAEABv1XMjVzZ7PWo1jjAnVR1kdqPXNwJOMcoGOUNpg$> ---------------------------------------------------------------------- ------------------------------------------------------------ -SECURITY/CONFIDENTIALITY WARNING- This message and any attachments are intended solely for the individual or entity to which they are addressed. 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