title: Why do GPs exclude patients from participating in research? An exploration of adherence to and divergence from trial criteria.
abstract: BACKGROUND
  The role of GPs in recruiting or excluding participants critically underpins the feasibility, external validity and generalizability of primary care research. A better understanding of this role is needed.
  
  
  OBJECTIVE
  To investigate why GPs excluded potentially eligible participants from a large scale randomized controlled trial (RCT), to determine the proportion of patients excluded on account of trial eligibility compared with other reasons, and to explore the impact of such exclusions on the management and generalizability of RCTs.
  
  
  METHODS
  Secondary analysis of data from the CoBalT study, a multi-centre general-practice-based RCT investigating cognitive behavioural therapy as an adjunct to pharmacotherapy for treatment-resistant depression.
  
  
  METHODS
  GPs were asked to screen patient lists generated from computerized record searches for trial eligibility and to provide narrative reasons for excluding patients. These reasons were coded independently by two researchers, with a third researcher resolving discrepancies.
  
  
  RESULTS
  Thirty-one percent (4750/15,379) of patients were excluded at the GP screening stage, including 663 on patient lists that remained unscreened. Of the 4087 actively excluded patients, 67% were excluded on account of trial exclusion criteria, 20% for other criteria (half of which were comorbid conditions) and 13% without reason.
  
  
  CONCLUSIONS
  Clear, comprehensive criteria, particularly with regards to comorbidities, are required for GPs to confidently screen patients for potential participation in research. Future studies should promote inclusivity and encourage GPs to adopt a liberal approach when screening patient lists. This would enhance the validity and generalizability of primary care research and encourage greater patient autonomy.
authors.affiliation: Primary Care Research Group, University of Exeter Medical School, Smeall Building, St Luke's Campus, Exeter, EX1 2LU, C.Jenkinson@exeter.ac.uk.
authors.forename: Caroline E
authors.initials: CE
authors.lastname: Jenkinson
authors.affiliation: Primary Care Research Group, University of Exeter Medical School, Smeall Building, St Luke's Campus, Exeter, EX1 2LU.
authors.forename: Rachel E
authors.initials: RE
authors.lastname: Winder
authors.affiliation: Mood Disorders Centre, Washington Singer Laboratories, University of Exeter, Exeter, EX4 4QG.
authors.forename: Holly V R
authors.initials: HV
authors.lastname: Sugg
authors.affiliation: Collaboration for the Advancement of Medical Education Research, Assessment, Peninsula Schools of Medicine and Dentistry, Plymouth University, Plymouth, PL4 8AA.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Roberts
authors.affiliation: Academic Unit of Mental Health and Wellbeing, Institute of Health and Wellbeing, University of Glasgow, Gartnavel Royal Hospital, Glasgow, G12 0XH, UK, TEKS, Les Toits Blancs, 23 Rue du Praya, 05100 Montgenevre, France and.
authors.forename: Nicola
authors.initials: N
authors.lastname: Ridgway
authors.affiliation: Mood Disorders Centre, Washington Singer Laboratories, University of Exeter, Exeter, EX4 4QG.
authors.forename: Willem
authors.initials: W
authors.lastname: Kuyken
authors.affiliation: School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Clifton, Bristol, BS8 2BN, UK.
authors.forename: Nicola
authors.initials: N
authors.lastname: Wiles
authors.affiliation: School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Clifton, Bristol, BS8 2BN, UK.
authors.forename: David
authors.initials: D
authors.lastname: Kessler
authors.affiliation: Primary Care Research Group, University of Exeter Medical School, Smeall Building, St Luke's Campus, Exeter, EX1 2LU.
authors.forename: John
authors.initials: J
authors.lastname: Campbell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015928:Cognitive Behavioral Therapy; D015897:Comorbidity; D003866:Depressive Disorder / Q000628:therapy; D005260:Female; D058005:General Practitioners; D019983:Guideline Adherence; D006801:Humans; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D010818:Practice Patterns, Physicians'; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D055815:Young Adult
keywords: Cognitive behavioural therapy; depression/mood disorder; medical comorbidity; mental health; practice-based research; primary care; randomized controlled trial; secondary data analysis.