title: The Non-Inferiority Margins in Migraine Research (NIMM) Survey.
abstract: OBJECTIVE
  To survey experts in Headache Medicine on their opinions regarding appropriate non-inferiority margins for outcomes commonly used in migraine research.
  
  
  METHODS
  Members of the American Headache Society and the Canadian Headache Society were invited to participate in the Non-Inferiority Margins in Migraine Research (NIMM) survey. Adult and child neurologists with expertise in Headache Medicine were eligible to participate. The survey had a multiple choice format and comprised questions on respondent characteristics, eligibility, as well as expert opinion on non-inferiority margins for outcomes commonly used in trials of both prophylactic and acute interventions for migraine.
  
  
  RESULTS
  Ninety-nine eligible respondents completed the survey. Most respondents were adult neurologists (84.9%) and 74% reported practicing in the USA. The following were the most commonly selected non-inferiority margins: (1) change in monthly migraine attacks comparing baseline to the treatment period: 1 attack (39.4% selecting), (2) change in monthly migraine days comparing baseline to the treatment period: 1 day (44.4%), (3) change in average migraine intensity on a 4-point scale comparing baseline to the treatment period: 1.0 (31.3%), (4) percentage of participants who are pain-free 2 hours after the intervention: 5% (41.4%), (5) percentage of participants who have a migraine recurrence within 48 hours of treatment: 5% (42.4%), and (6) percentage of participants with sustained pain freedom: 5% (42.4%).
  
  
  CONCLUSIONS
  The results of the NIMM survey describe the opinions of a group of experts on appropriate non-inferiority margins for outcomes commonly used in migraine clinical trials. There was significant variability in responses and lack of consensus on the choice of non-inferiority margins. The survey did not incorporate the patient perspective and was not validated prior to distribution. Further work in this area is required in order to explore how to incorporate clinical considerations into the selection of non-inferiority margins for migraine research.
authors.affiliation: University of Ottawa, Ottawa, ON, Canada.|Children's Hospital of Eastern Ontario, Ottawa, ON, Canada.
authors.forename: Serena L
authors.identifier: http://orcid.org/0000-0002-2879-811X
authors.initials: SL
authors.lastname: Orr
authors.affiliation: University of Ottawa, Ottawa, ON, Canada.|The Ottawa Hospital, Ottawa, ON, Canada.
authors.forename: Timothy
authors.initials: T
authors.lastname: Ramsay
authors.affiliation: University of Ottawa, Ottawa, ON, Canada.|The Ottawa Hospital, Ottawa, ON, Canada.
authors.forename: Suzanne N
authors.initials: SN
authors.lastname: Christie
authors.affiliation: Mayo Clinic College of Medicine, Phoenix, AZ, USA.
authors.forename: David
authors.initials: D
authors.lastname: Dodick
authors.affiliation: Toronto Rehabilitation Institute, Toronto, ON, Canada.|The Hospital for Sick Children, Toronto, ON, Canada.|Gladstone Headache Clinic, Toronto, ON, Canada.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Gladstone
authors.affiliation: University of Ottawa, Ottawa, ON, Canada.|The Ottawa Hospital, Ottawa, ON, Canada.
authors.forename: Dar
authors.initials: D
authors.lastname: Dowlatshahi
mesh_terms: D035843:Biomedical Research / Q000592:standards*; D002986:Clinical Trials as Topic / Q000592:standards*; D006801:Humans; D008881:Migraine Disorders / Q000628:therapy*; D000072141:Neurologists / Q000706:statistics & numerical data*; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*
keywords: migraine; non-inferiority trials; survey; trial design