title: Screen failure data in clinical trials: Are screening logs worth it?
abstract: BACKGROUND
  Clinical trials frequently spend considerable effort to collect data on patients who were assessed for eligibility but not enrolled. The Consolidated Standards of Reporting Trials (CONSORT) guidelines' recommended flow diagram for randomized clinical trials reinforces the belief that the collection of screening data is a necessary and worthwhile endeavor. The rationale for collecting screening data includes scientific, trial management, and ethno-socio-cultural reasons.
  
  
  OBJECTIVE
  We posit that the cost of collecting screening data is not justified, in part due to inability to centrally monitor and verify the screening data in the same manner as other clinical trial data.
  
  
  METHODS
  To illustrate the effort and site-to-site variability, we analyzed the screening data from a multicenter, randomized clinical trial of patients with transient ischemic attack or minor ischemic stroke (Platelet-Oriented Inhibition in New Transient Ischemic Attack and Minor Ischemic Stroke (POINT)).
  
  
  RESULTS
  Data were collected on over 27,000 patients screened across 172 enrolling sites, 95% of whom were not enrolled. Although the rate of return of screen failure logs was high overall (95%), there were a considerable number of logs that were returned with 'no data to report' (23%), often due to administrative reasons rather than no patients screened.
  
  
  CONCLUSIONS
  In spite of attempts to standardize the collection of screening data, due to differences in site processes, multicenter clinical trials face challenges in collecting those data completely and uniformly. The efforts required to centrally collect high-quality data on an extensive number of screened patients may outweigh the scientific value of the data. Moreover, the lack of a standardized definition of 'screened' and the challenges of collecting meaningful characteristics for patients who have not signed consent limits the ability to compare across studies and to assess generalizability and selection bias as intended.
authors.affiliation: Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA elmj@musc.edu.
authors.forename: Jordan J
authors.initials: JJ
authors.lastname: Elm
authors.affiliation: Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Palesch
authors.affiliation: Department of Neurology, University of California, San Francisco, San Francisco, CA, USA Department of Epidemiology & Biostatistics, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: J Donald
authors.initials: JD
authors.lastname: Easton
authors.affiliation: The EMMES Corporation, Rockville, MD, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: Lindblad
authors.affiliation: Department of Emergency Medicine, University of Michigan, Ann Arbor, MI, USA.
authors.forename: William
authors.initials: W
authors.lastname: Barsan
authors.affiliation: Department of Emergency Medicine, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Silbergleit
authors.affiliation: National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
authors.forename: Robin
authors.initials: R
authors.lastname: Conwit
authors.affiliation: Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Catherine
authors.initials: C
authors.lastname: Dillon
authors.affiliation: Department of Neurology, University of California, San Francisco, San Francisco, CA, USA Department of Epidemiology & Biostatistics, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Farrant
authors.affiliation: Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Holly
authors.initials: H
authors.lastname: Battenhouse
authors.affiliation: Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Perlmutter
authors.affiliation: Department of Neurology, University of California, San Francisco, San Francisco, CA, USA Department of Epidemiology & Biostatistics, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: S Claiborne
authors.initials: SC
authors.lastname: Johnston