title: What change in outcomes after cardiac arrest is necessary to change practice? Results of an international survey.
abstract: Efficient trials of interventions for patients with out-of-hospital cardiac arrest (OHCA) should have adequate but not excess power to detect a difference in outcomes. The minimum clinically important difference (MCID) is the threshold value in outcomes observed in a trial at which providers should choose to adopt a treatment. There has been limited assessment of MCID for outcomes after OHCA. Therefore, we conducted an international survey of individuals interested in cardiac resuscitation to define the MCID for a range of outcomes after OHCA.
  
  
  
  A brief survey instrument was developed and modified by consensus. Included were open-ended responses. The survey included an illustrative example of a hypothetical randomized study with distributions of outcomes based on those in a public use datafile from a previous trial. Elicited information included the minimum significant difference required in an outcome to change clinical practice. The population of interest was emergency physicians or other practitioners of acute cardiovascular research.
  
  
  
  Usable responses were obtained from 160 respondents (50% of surveyed) in 46 countries (79% of surveyed). MCIDs tended to increase as baseline outcomes increased. For a population of patients with 25% survival to discharge and 20% favorable neurologic status at discharge, the MCID were median 5 (interquartile range [IQR] 3, 10) percent for survival to discharge; median 5 (IQR 2, 10) percent for favorable neurologic status at discharge, median 4 (IQR 2, 9) days of ICU-free survival and median 4 (IQR 2, 8) days of hospital-free survival.
  
  
  
  Reported MCIDs for outcomes after OHCA vary according to the outcome considered as well as the baseline rate of achieving it. MCIDs of ICU-free survival or hospital-free survival may be useful to accelerate the rate of evidence-based change in resuscitation care.
authors: University of Washington, Seattle, WA, USA.
authors: Graham
authors: G
authors: Nichol
authors: University of Washington, Seattle, WA, USA.
authors: Siobhan P
authors: SP
authors: Brown
authors: University of Warwick, Warwick, UK; Heart of England NHS Foundation Trust, Coventry, UK.
authors: Gavin D
authors: GD
authors: Perkins
authors: University of Washington, Seattle, WA, USA.
authors: Francis
authors: F
authors: Kim
authors: Medical University of Vienna, Vienna, Austria.
authors: Fritz
authors: F
authors: Sterz
authors: University of Washington, Seattle, WA, USA.
authors: Jo Ann
authors: JA
authors: Broeckel Elrod
authors: University of Athens Medical School, Athens, Greece.
authors: Spyros
authors: S
authors: Mentzelopoulos
authors: University of Surrey, Guildford, Surrey, UK.
authors: Richard
authors: R
authors: Lyon
authors: King Saud Bin Abdulaziz University for Health Sciences and King Abdullah International Medical Research Center, Riyadh, Saudi Arabia.
authors: Yaseen
authors: Y
authors: Arabi
authors: Department of Emergency Medicine and Services, Helsinki University Hospital and Helsinki University, Helsinki, Finland.
authors: Maaret
authors: M
authors: Castren
authors: University of Otago, Wellington, New Zealand.
authors: Peter
authors: P
authors: Larsen
authors: University of Arizona, Tucson, AZ, USA.
authors: Terence
authors: T
authors: Valenzuela
authors: University Hospital Schleswig-Holstein, Germany.
authors: Jan-Thorsten
authors: JT
authors: Graesner
authors: University of Utah, Salt Lake City, UT, USA.
authors: Scott
authors: S
authors: Youngquist
authors: Department of Emergency Medicine & Narenthorn EMS Center Rajavithi Hospital, Ministry of Public Health, Thailand.
authors: Nalinas
authors: N
authors: Khunkhlai
authors: University of Alabama at Birmingham, Birmingham, AL, USA.
authors: Henry E
authors: HE
authors: Wang
authors: Prague EMS, Prague, Czech Republic.
authors: Franek
authors: F
authors: Ondrej
authors: Academia Mexicana de Medicina Prehospitalaria, Mexico.
authors: Juan Manuel Fraga
authors: JM
authors: Sastrias
authors: Aga Khan University, Nairobi, Kenya.
authors: Anders
authors: A
authors: Barasa
authors: University of Washington, Seattle, WA, USA.
authors: Michael R
authors: MR
authors: Sayre
mesh_terms: D016887:Cardiopulmonary Resuscitation / Q000009:adverse effects / Q000379:methods; D000066891:Critical Care Outcomes; D004632:Emergency Medical Services / Q000379:methods / Q000458:organization & administration; D006302:Health Services Research / Q000458:organization & administration; D006801:Humans; D007391:International Cooperation; D058687:Out-of-Hospital Cardiac Arrest / Q000628:therapy*; D011795:Surveys and Questionnaires; D016019:Survival Analysis
keywords: Cardiac arrest; Methods; Randomized trails; Survey