title: Accounting for repeat enrollments during an emergency clinical trial: the Rapid Anticonvulsant Medications Prior to Arrival Trial (RAMPART).
abstract: OBJECTIVE
  The objectives were to describe the frequency of repeat enrollment within a specific exception from informed consent trial testing benzodiazepine treatment of prehospital status epilepticus and to estimate the effect of repeat enrollments on the analysis of the primary outcome.
  
  
  METHODS
  This was a secondary analysis of data collected as part of the Rapid Anticonvulsant Medication Prior to Arrival Trial (RAMPART), a study comparing intramuscular midazolam to intravenous lorazepam given by paramedics to patients with prehospital status epilepticus. Subjects in RAMPART achieved a successful primary outcome if they had cessation of seizures by the time of emergency department arrival. Data were collected on all subjects, but only the first enrollment for each individual was used in the primary analysis. The patterns of repeat enrollment are described, along with the demographics of these subjects. In addition, an intraclass correlation coefficient (ICC) was estimated to assess the amount of within-subject correlation and its effect on the estimated treatment effect when all enrollments are included in the analysis.
  
  
  RESULTS
  A total of 1,023 enrollments occurred in RAMPART among 893 unique individuals (range of repeat enrollment observed = two to 14). The ICC for seizure cessation within individual was low at 0.119; when excluding subjects with benzodiazepine crossover, the ICC was 0.094.
  
  
  CONCLUSIONS
  In clinical trials of emergency conditions with interval complete resolution, accounting for repeat enrollments is feasible. The RAMPART experience demonstrated that in this setting the within-subject correlation is low and can be accounted for at relatively low statistical cost.
authors.affiliation: The Department of Emergency Medicine, University of Michigan, Ann Arbor, MI; The Department of Neurology, University of Michigan, Ann Arbor, MI.
authors.forename: William J
authors.initials: WJ
authors.lastname: Meurer
authors.forename: Robert
authors.initials: R
authors.lastname: Silbergleit
authors.forename: Katherine S
authors.initials: KS
authors.lastname: Nicholas
authors.forename: James F
authors.initials: JF
authors.lastname: Burke
authors.forename: Valerie
authors.initials: V
authors.lastname: Durkalski
mesh_terms: D000328:Adult; D000368:Aged; D000488:Allied Health Personnel; D000927:Anticonvulsants / Q000008:administration & dosage / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D007275:Injections, Intravenous; D008140:Lorazepam / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008874:Midazolam / Q000008:administration & dosage / Q000627:therapeutic use*; D008875:Middle Aged; D044469:Racial Groups; D012107:Research Design; D013226:Status Epilepticus / Q000188:drug therapy*
chemical_list: D000927:Anticonvulsants; D008140:Lorazepam; D008874:Midazolam